Injury classification [link]
Terms used to describe injuries [link]
Describing injuries [link]
Body diagrams [link]
Progression of bruising with time [link]
Lacerations, abrasions, and scratches [link]
Incised wounds [link]
Stab wounds [link]
Slash wounds [link]
Skin wound healing [link]
Defence injuries [link]
Intimate partner violence and abuse [link]
Elder abuse and neglect [link]
Scalp injury and skull fracture [link]
Primary brain injury [link]
Traumatic intracranial haemorrhage [link]
Further complications of brain injury [link]
Facial injuries [link]
Spinal injury [link]
Chest injury [link]
Abdominal injury [link]
Fractures of the pelvis and extremities [link]
Explosive injuries [link]
Investigations after an explosion [link]
Rifled gunshot injuries [link]
Shotgun injuries [link]
Within a forensic context, the interpretation and classification of injuries is important in helping to gain an insight into how they were caused.
Is it an injury?
Certain natural disease processes can masquerade as injuries. On occasions, normal appearances can be mistaken for an injury. On this basis, the first important question to be answered is whether there really has been an injury. This question particularly applies in the field of child abuse, where there are two classic errors:
• A Mongolian blue spot over the lower back of some children may be mistaken for bruising.
• Thrombocytopenia, purpura, and bleeding tendencies from any cause may also be mistaken as bruising of purely traumatic origin.
Avoid inappropriate terminology
The importance of applying the correct terminology when describing injuries in a medicolegal context cannot be overstated. Many practitioners in forensic and other fields have learnt this to their cost, embarrassment, and sometimes even ridicule (as occurred when Emergency Medicine specialists wrote in the British Medical Journal about a ‘neatly incised laceration’). Inherent in the meaning of certain terms used to describe an injury is an implication regarding the mechanism responsible for causing that injury. This particularly applies to skin wounds, where some descriptive terms imply that the injury resulted from blunt force (e.g. laceration, abrasion), whereas others imply sharp force (e.g. incised wound). The potential medicolegal implications are obvious. It is more than simply sloppy to describe an incised skin wound which resulted from a person being stabbed by a knife as a ‘laceration’—it is incorrect. In a courtroom setting, if one aspect of the testimony of a witness is shown to be wrong, doubt may be cast over the remainder of his/her testimony and credibility. Sometimes it can be difficult for a non-expert (or even an expert) to judge whether a particular skin wound is an incised wound or a laceration—in this instance, it may be prudent to carefully document the findings (as outlined on [link]) and describe it simply as a ‘skin wound’.
Problems with terminology
Having warned against use of inappropriate terminology to describe injuries, it is only fair to acknowledge that the meanings of some terms used to describe injuries are not generally agreed (and for this reason some are perhaps best avoided). Even the meaning of the term ‘wound’ is not universally agreed—some authorities apply it to any injury, whilst others restrict its use to injuries which involve a breach in the skin. As many jurisdictions have precise definitions of a ‘wound’, the term should be used with caution.
Given that language is designed to aid communication, it may appear surprising that there is such an array of terms used to describe injury from a forensic perspective. Some might interpret this as a conspiracy to maintain medical ‘elitism’—a view not contradicted by the fact that definitions of many of the terms are not generally agreed! The following principal terms used to describe injuries are discussed in more detail in subsequent pages.
Abrasions to the skin typically reflect blunt force trauma applied tangentially (also known as ‘grazes’ or ‘scrapes’), denuding the superficial skin. The term may also be used to cover damage to the superficial layers of skin by compression—these include patterned abrasions, where the imprint of an item is stamped onto the skin.
Avulsion is the term applied when a structure is ripped forcefully away from its normal attachments. It may be applied in a variety of situations (e.g. when the kidney becomes detached from its vascular pedicle, or when a piece of bone is plucked away by a tendon).
Blast injuries reflect transmission of a narrow wave of very high pressure.
Blunt force trauma describes a general mechanism of injury.
Bruises are extravascular collections of blood which are more than a few mm in diameter.
Burns usually reflect thermal skin injury, although the term is also applied to chemical skin damage and thermal damage to other epithelial surfaces (e.g. the pharynx).
Chop wounds, such as those caused by an axe or machete, have features of both blunt force and sharp force trauma.
Contusions are bruises, although use of this term has no particular advantage.
Cuts are skin wounds, but the term means different things to different people—some consider them to be incised (particularly slash) wounds, whilst colloquially the term often covers any sort of skin wound.
Defence injuries are patterns of injury which imply that an individual was trying to defend him/herself against attack. These include an isolated ulna shaft fracture resulting from an individual raising an arm to protect him/herself from attack from a baseball bat (‘nightstick injury’) and incised wounds to the palm of the hand as a victim being attacked by a person wielding a knife tries to grab it.
Ecchymoses are small bruises.
Entry and exit wounds reflect interpretations of causation relating to penetrating trauma.
Factitious wounds are self-inflicted wounds which are caused in an attempt to create the false impression of having been sustained in an assault by someone else.
Fractures is a term which covers all types of breaks to bones, although the term can also be applied to other organs (e.g. the erect penis).
Haematomas are large collections of blood following haemorrhage.
Haemorrhages are areas of bleeding.
Incisions or incised wounds follow sharp force trauma.
Lacerations are full thickness skin wounds which follow blunt trauma where the tissues are crushed and/or torn or split apart. The term may also be applied to damage to rupture of solid internal organs.
Penetrating trauma is usually applied to the situation when objects pierce the skin.
Perforating injury describes events in which an object penetrates into a cavity or where a normally contained organ (such as the stomach) bursts open.
Petechial haemorrhages are tiny areas of bleeding (typically of <2mm diameter), and often follow indirect trauma. There is a traditional association between this term and asphyxial injury (see [link]).
Puncture wounds can affect a number of organs, but when applied to the skin, form a part of some bite injuries. The term implies relatively deep penetration with a small skin wound.
Scalds are thermal injuries to the skin caused by hot liquids/steam.
Scratches may include a variety of different injuries, but are typically applied to skin wounds caused by fingernails (‘scratch abrasions’narrow linear abrasions to the skin), but also cover other injuries (e.g. ‘point scratches’—superficial incised wounds caused by the tip of a sharp object such as a knife).
Sharp force trauma describes the mechanism of injury. It includes knife stab and slash wounds.
Slash wounds are incised wounds which are longer than they are deep.
Stab wounds are deeper than they are long, and are mostly caused by sharp force (typically knives).
Transfixing injury describes through and through penetration of part of the body.
Wounds usually affect the skin, but the term is often applied to injuries elsewhere. Its meaning may depend to some extent upon who uses it and in what context. Note that in English law, for example, ‘wounding’ is defined as an injury which penetrates or breaks all of the layers of the skin.
It is important for the forensic practitioner to record injuries in an accurate fashion. It is worth trying to develop a system which ensures that all of the important elements are considered and recorded. Wherever possible, appropriate body diagrams should be used. This particularly applies to the occasions where there are complex or numerous injuries—here it is advisable to number the injuries and cross-reference written descriptions with numbers applied to a body diagram (see [link]).
All of the following elements need to be considered.
Type and nature of injury
The findings should be described exactly as they appear.
• Bruises—the colour needs to be recorded and most particularly, whether there is any yellow colour present (this has implications in relation to dating the injury—see [link]). A ruler needs to be used to accurately measure the dimensions, including both length and width (employing metric measurements). For example: ‘the yellow/brown bruise measured 4.5cm (horizontally) x 2.5cm (vertically)’. Any particular patterns or shapes should be described, but reference to size in terms of everyday objects should be avoided (e.g. stating that a bruise is the ‘size of an egg’ is unhelpful, especially considering that eggs come in different sizes. The presence/absence of any swelling and/or tenderness should be specifically searched for and documented.
• Skin wounds—these need to be measured accurately with a ruler, with comment on the depth and stating if deep structures are visible and if there is any contamination with dirt or other foreign material. The orientation of the wound (vertical, horizontal, oblique, etc.) also needs to be recorded. If possible, an attempt should be made to judge the nature of any wound and ascribe the appropriate term (e.g. ‘laceration’ or ‘incised wound’). However, if the exact nature of an injury is unclear, this should be documented. For those wounds which have been treated and closed at hospital, it is appropriate to record the number and nature of the sutures used and/or any adhesive paper strips.
• Abrasions—the size, orientation, and depth should be described and the presence of any patterns or skin tags recorded.
• Burns—the colour and nature of the burn (including any blistering) should be recorded. In the conscious patient, it is important to check for sensation over the burnt skin which will assist attempts to make a judgement about depth.
Location of injury
The exact position of an injury should be recorded using standard anatomical terms and the distance of the injury from a definite point measured (e.g. ‘the distal extent of the skin wound was situated along the ulnar border of the mid-forearm at a distance of 9cm from the proximal palmar crease’).
Clinical evidence of underlying damage (e.g. inability to weight bear suggesting fracture, reduced air entry implying pneumothorax) needs to be carefully searched for, as it might not be otherwise immediately apparent. In the case of skin wounds which penetrate the skin, it is important to check as appropriate for nerve, tendon, or vessel injury and test for distal sensation, movements, and pulses.
In certain instances, photographs can convey an enormous amount of useful information about the nature and extent of injuries. They have a particularly important role in the investigation and analysis of suspected bite wounds (see [link]). Photographs taken by SOCOs usually employ a standard L-shaped ruler in order that distortion in two planes can be accounted for. Digital photographs are increasingly being used. It is worth remembering that colour reproduction is not necessarily accurate and that colours 'on screen' might be significantly different to the originals.
An example of a standard recommended body diagram is shown in Fig. 5.1. Copies of standard diagrams can be obtained from the (publications section of the) Faculty of Forensic and Legal Medicine's website ( http://www.fflm.ac.uk).
Injuries (see Fig. 5.1)
1 3.5cm (horizontally) x 4.5cm (vertically) red bruise with tenderness.
2 2.7cm superficial linear scratch abrasion.
3 Faint yellow bruising over an area of approximately 6cm x 6cm.
4 3.0cm long incised wound exposing subcutaneous tissues.
5 Organized old scabbed wound measuring approximately 4cm (horizontally) x 5cm (vertically).
6 Healed white linear oblique scar measuring 8.5cm in length.
Bruising results from damage to blood vessels which have bled into adjacent tissues. It is associated principally with blunt force trauma. Although usually applied to damage to the skin and subcutaneous tissues, bruising can affect deep organs also.
Forensic medicine has many areas of confusing terminology, perhaps no more so than in relation to the descriptions of bruises. The cynic might be forgiven for thinking that the multitude of terms in use is designed to confuse the non-specialist. The aim should be to record findings using simple descriptive terms with the expectation that these may need to be explained in a court! See [link] for explanations of various terms in common use, including contusion, ecchymosis, haematoma, petechiae. ‘Bruise’ is the basic term which covers most forms of bleeding larger than a few mm in diameter.
Characteristic skin bruising
The appearance of bruising reflects a variety of factors other than simply the mechanism of injury. In particular, bruising looks different depending upon the thickness, colour, and nature of the overlying skin.
Bruising confined to the superficial parts of the skin may cause an accurate imprint (e.g. the sole of a boot which inflicted a stamp).
Bruising from gripping fingertips is often seen on the inner aspect of the upper arms of individuals who have been restrained.
Two parallel straight lines of bruising separated by a pale central part reflect blunt trauma from a cane, rod, snooker cue, or other linear object (see Fig. 5.2).
Bruising in specific sites
Bruising which appears over the mastoid process behind the ear in the absence of any direct trauma indicates base of skull fracture. The bruising is not immediately apparent, but typically takes several days to ‘come out’.
Movement of red blood cells in the early period after death follows a relatively predictable course, as covered on [link]. However, quite distinct from this process, much attention has previously been devoted to a different phenomenon—that of postmortem bruising. Although it has been reliably described, bruising occurring within the first few hours after death appears to be really quite unusual.
It is often very important from a medicolegal perspective to try to ascertain exactly when injuries occurred. Unfortunately, there is a dearth of reliable science to assist with this, although the testimony of certain experts over the years may not always have given this impression! Bruises do not follow the traditional account of the progression through various colours, which may be summarized as follows:
Time after injury
• 0–2 days
Swollen, tender, red/blue
• 3–5 days
• 5–7 days
• 7–10 days
• 10–14 days
• 14–28 days
• Different individuals will have different interpretations of the colours that they see.
• Bruising looks different in different lighting.
• Bruises often become more prominent hours or even days after the initial injury.
• Similar bruises in the same individual may go through colour change at a different rate.
• Different colours in a bruise may coexist.
• Research from one of the authors suggests that in one family, most bruises amongst three siblings disappeared within 3 days!
Consistently, evidence does indicate that with the possible exception of young infants:
A yellow colour in a bruise implies that it is >18h old.
Other factors which may help an expert make an informed guess about the age of bruising include:
• Tenderness and/or swelling tend to imply a relatively recent origin.
• A fresh patterned bruise superimposed upon an area of fading bruising implies separate injuries occurring at very different times (potentially important from a forensic perspective).
• Bruising in certain sites tends to move slowly with time under the influence of gravity—hence an injury to the mid-calf not infrequently results in bruising around the ankle a few days later. Much more useful information is available from examination of a ‘live’ individual, rather than inspection of photographs.
Skin lacerations (Fig. 5.3)
Lacerations to the skin are caused by blunt force trauma in which the skin is torn apart by a crushing/shearing force. Skin lacerations may exhibit the following features:
• Ragged, irregular skin edges.
• Bruising of the skin edges which have obviously been crushed.
• Contamination of the wound (sometimes by forensically important and collectable trace material).
• Varying depths and breadths of the wound in different places.
• Bridging of tissues within the wound, reflecting certain stronger elements within the wound remaining intact (e.g. nerves and blood vessels).
• Abrasion of part of the wound margin.
• Presence of intact hairs which cross the wound.
Lacerations of the skin tend to occur at sites where there are underlying bony prominences. Lacerations around the eyebrows are relatively common in individuals who fall and hit the ground under the influence of alcohol: the scalp being split apart as it is crushed between skull bone and hard ground. Once a wound has been cleaned and satisfactorily closed, it may be very difficult to determine with confidence whether it was a laceration or an incised wound. Therefore, it is important that this issue is considered prior to closure.
Abrasions are ‘grazes’ or ‘scrapes’. Most result from blunt force trauma being applied tangentially. They are typically superficial in that they do not involve the full thickness of the skin, although occasionally fully thickness wounds occur. Contact against a wide rough surface causes wide abrasions which are sometimes referred to as ‘brush abrasions’. It may be possible to determine the direction in which the abrasion occurred by observing small epidermal skin tags at that edge of the wound which was last in contact with the abrading surface.
The terms ‘impact’ and ‘patterned’ abrasions are sometimes used to describe blunt force injuries which are at right angles to the skin.
Ageing of abrasions
Histologically, infiltration of polymorphs is obvious by 4–8h after injury—the important issue is that this implies that the injury occurred whilst the patient was alive. Similarly, macroscopically, scab formation reflects injury during life. Abrasions can occur after death, in which case there is no inflammatory response apparent histologically. Macroscopically, postmortem abrasions are yellow (rather than red) and tend to appear translucent.
This is another slightly ambiguous term, which has been defined in different ways. However, most forensic practitioners are happy with the idea that linear abrasions may defined as scratches.
Scratch abrasions caused by fingernails are the most frequent scratches seen in clinical practice. Typically, several relatively narrow linear wounds of similar depth may run together in parallel or slightly converging fashion. Note that it may be possible to collect forensically important trace material (DNA) from under the fingernail of the person who inflicted the injury.
Point scratches are incised wounds of superficial nature which are caused by the tip of a sharp object (e.g. knife or broken glass) running across the skin.
As already mentioned earlier in this chapter, from a forensic perspective, the key issue when interpreting an injury is often to diagnose the nature of the injury in order to determine whether a wound was caused by blunt or sharp force trauma. Incised wounds follow sharp force injury and may be caused by any object which has a sharp edge, most usually knives and the sharp edges of broken glass. Incised wounds typically exhibit the following characteristics:
• The skin wound is linear in nature.
• There is an absence of adjacent bruising of the skin edges.
• There is an absence of ‘bridging’ tissue extending from one side to the other within the wound (as is often seen in lacerations).
• In the case of hair covered areas, such as the scalp, there may be divided hairs lying free in or around the wound.
Note that incised wounds which penetrate obliquely (tangentially) through the skin will inevitably result in one skin edge being ‘undercut’ when compared with the other.
It can sometimes be very difficult to judge whether a particular wound is an incised wound or a laceration—in this instance, simply record and describe the findings, and document it as a ‘wound’. It is worth bearing in mind the fact that skin wounds which overlie bone can sometimes have relatively ‘clean’ edges, so it is important to look carefully for other features, such as underlying structural damage, particularly linear ‘scoring’ of the periosteum resulting from sharp force injury.
Traditional nomenclature divides incised wounds into ‘slash’ wounds and ‘stab’ wounds as follows:
• Stab wounds are deeper than they are long.
• Slash wounds are longer than they are deep.
It may be best to avoid use of the term ‘cut’ which can be confusing, is really rather non-specific, and is frequently used by members of the general population to cover any skin wound which bleeds, whether it is an incised wound, laceration, or abrasion.
Characteristic incised wounds
There are occasions when the wound resulting from an injury is so characteristic that it can provide a ‘forensic’ match for a particular weapon and mechanism. The pattern of injury, combined with findings on examination may suggest defence injuries (see [link]), or self-inflicted injuries (see [link]).
It is no surprise that surgeons typically choose to inflict incised skin wounds upon their patients. With minimal damage to adjacent tissues, these wounds combine the potential advantages of rapid healing, minimal scarring, with a low risk of infection.
On the Ides of March (15 March) 44 BC, the Roman dictator (Gaius) Julius Caesar was assassinated in Rome. He was killed by a group of 60 conspirators who inflicted a total of 23 stab wounds on him. According to one report, a physician who examined him afterwards stated that it was a wound to his chest that was the fatal injury. Legend has it that when Caesar saw Brutus amongst the conspirators, he said to him ‘You too, Brutus?’, an account which was immortalized in Shakespeare's Julius Caesar as ‘Et tu, Brute?’ Other less dramatic but possibly more accurate accounts, reported that Caesar said nothing during the attack, but simply used his toga to hide his face.
In addition to the incised wounds that killed him, Caesar's name is strongly and obviously associated with medical incisions in the form of a ‘Caesarean section’. The exact origin of the term, however, remains somewhat obscure.
For most people, the term ‘stabbing’ conjures up an image of an assault involving a knife. This is not unreasonable, given the prevalence of knife injuries, a small but significant proportion of which result in fatalities. Indeed, knife wounds are responsible for the majority of homicidal deaths in the UK. Having acknowledged the role of knives, it should be remembered that stab wounds can be caused by many other different types of pointed implements (including scissors, screwdrivers, pencils, and even stiletto heels). Occasionally, stabbings are unintentional (‘accidental’) or self-inflicted. Although understandably classed as incised wounds, stab wounds can sometimes be inflicted by objects with a relatively blunt tip (e.g. a pencil), provided that sufficient force is used.
The trouble with stab wounds
In most instances, concerns around stab wounds reflect obvious potential for severe internal injuries, with the external (skin) wound identifying this possibility. The most obvious concern relates to massive concealed internal haemorrhage due to direct damage to large blood vessels. In the case of the chest, pneumothorax (particularly tension pneumothorax) and cardiac tamponade present additional threats. Neck stabbings may cause airway obstruction, air embolism, or spinal cord injury. Stab wounds to the neck and/or trunk (as opposed to the limbs) understandably arouse most concern. However, significant hypovolaemia and even death from massive external haemorrhage may occur following limb stabbing, particularly where the victim is not in a position to seek or receive appropriate medical attention (e.g. those heavily under the influence of alcohol and/or drugs).
Forensic examination of stab wounds
From a forensic perspective, scrutiny of the skin wound can provide crucial information about how an injury was caused. The classical picture is of a victim with an obliquely orientated incised skin wound over the front of the left chest which was inflicted by a right-handed assailant directly facing the victim and holding the knife in a traditional dagger fashion (thumb gripping furthest away from the blade). However, many simple factors, such as movement of the two parties can alter this.
• Scissors can produce a variety of wounds depending upon their design and whether they are open or closed at the time of injury. A closed pair of scissors typically has a relatively blunt tip and so tends to split the skin causing a Z-shaped wound. A protruding screw in the blades of the scissors may also cause a small laceration in the middle of one wound.
• Broken bottles can cause numerous grouped incised skin wounds of varying shapes, sizes, and depths.
• Traditional screwdrivers and chisels typically produce rectangular wounds with abraded margins.
• Cross-head screwdrivers cause characteristic X-shaped wounds.
Forensic practitioners are not often directly involved in providing emergency care for victims of stabbings, but do need to appreciate the principles of standard treatment.
When faced with a patient who still has the stabbing object in situ, it should be left in place, as the foreign object may be providing tamponade—release might result in torrential haemorrhage. Concepts underpinning management of penetrating trauma have changed considerably in recent years. The principal risk is acknowledged to be haemorrhage. In the past, treatment focused around intravenous fluid replacement and haemodynamic stabilization prior to transfer. However, research evidence has shown that patients with significant haemorrhage have a better outcome if intravenous fluid replacement is kept to a minimum and they are transported as rapidly as possible for definitive treatment (usually surgery at hospital). On this basis, having provided oxygen, decompressed any tension pneumothorax, and applied pressure to external bleeding, ambulance services now tend towards a policy of ‘scoop and run’ rather than ‘stay and play’ at the scene.
Hospital staff aim to quickly identify and treat immediately life-threatening injuries. Any pneumothorax is drained using a large intercostal tube—unfortunately, hospital staff still sometimes continue to insert these through stab wounds, thereby destroying the forensic evidence and increasing the risk of infection. Continuing the aim of the prehospital services, hospital staff look to provide those patients who require definitive surgery for haemorrhagic shock with this treatment as soon as possible.
Procedure after death is declared at hospital
Many of those who die having been stabbed are taken to hospital, either with a pulse or without, for resuscitative efforts. Cardiac arrest at hospital following penetrating trauma is an indication for emergency thoracotomy. This, combined with other attempts at resuscitation, will necessarily result in significant effects on the body as far as subsequent forensic examination is concerned. The following may help hospital staff faced with this situation:
• Attempts at resuscitation should take precedence over initial concerns about gathering forensic evidence.
• Once death is declared, police will advise about collection of evidence.
• All lines, tubes, and therapeutic devices should be left in place, together with any embedded foreign body (e.g. knife).
• Resuscitating staff need to make detailed contemporaneous notes (using diagrams), particularly of resuscitative efforts and injuries. This will help the forensic pathologist to distinguish injuries which were inflicted as part of any assault from those associated with resuscitative efforts (e.g. insertion of intercostal chest drains).
• The hospital press officer should expect considerable interest.
Knife anatomy (Fig. 5.5)
Knives come in many different shapes and designs. As a result, when used as weapons, different knives inflict very different patterns of injury. The typical ‘anatomical’ features of knives are shown in the figure below. The two basic components are the blade (almost universally metal) and the handle (made of a variety of materials). Knives and in particular, blades, come in numerous shapes, sizes and designs. The tip or point may be sharp or blunt, and there may be one or two sharp edges—in the case of just one sharp edge, the opposite side is a blunt back. As the blade extends towards the handle it typically widens and the sharp edge finishes. This results in an area of the blade adjacent to the handle with two blunt edges (ricasso). Where the blade meets the handle, there is traditionally an expansion of the handle into a guard. The main part of the handle serves as the grip.
Identifying the weapon
It is clearly easiest to identify the knife responsible for an injury when it is left embedded in the body! Not infrequently, part of the blade breaks off and is left behind as the remainder of the weapon is removed—this then opens the potential for a match. In most other instances, however, it is impossible to make a certain match solely based upon the nature of the wound. The most that can usually be said is that a particular knife would have been capable of (‘consistent with’) causing a particular wound. However, certain wound characteristics imply certain knife features, as considered in the following section. Forensic examination of a knife may reveal vital clues, in terms of DNA and fingerprints.
In addition to stab wounds, knives can inflict slash wounds and superficial point scratch abrasions (see [link]), as well as blunt trauma from the handle. Features of stab wounds reflect a variety of factors, as follows:
• Orientation of skin wounds affects appearance in that wounds tend to gape more when they cross Langer's lines, but remain narrow slits when parallel to them.
• Double sharp-edged blades can cause linear wounds with two ‘pointed’ or V-shaped ends.
• Single sharp-edged blades can result in one pointed end and one ‘fish-tail’ or ‘squared off’ wound, the latter reflecting localized blunt trauma from the blunt edge, with localized tearing and bruising of the skin. Note, however, that some single-edged knives have a sharp edge on the back at the very tip, so that the initial penetration is from a double edged weapon, and if the knife is then moved down towards the large sharp edge, the blunt edge makes no contact, so the wound has two pointed ends.
• Serrated blades may cause characteristic serrations of the stab wound or adjacent skin.
• Movement (of the knife or victim) alters the shape of wounds. An L-shaped wound may reflect the knife being twisted in the body, or movement of the body as the knife is withdrawn. Within the limits of 1mm or 2mm skin elasticity, the skin wound is at least as long as the blade is wide at any particular point, but clearly it can be much longer—measure the wound with the edges apposed.
• Compression of the subcutaneous tissues by a knife thrust with some force may allow a blade to penetrate a depth which is longer than the blade, when measured under normal (non-compressed) conditions. This applies more to the abdomen and buttocks than to the chest.
• Penetration to the ricasso may result in double fish-tails at wound ends.
• Imprints and/or bruising from the guard may also result from complete penetration—the area of maximal prominence bruising may indicate whether the knife was inserted with up- or downwards force. In the latter case, there will be more bruising above the wound.
How much force was required?
This is a frequently asked question in a court-room setting as the answer may have implications relating to the mechanism of injury and mens rea. However, it is possible to answer this question in general terms only, rather than with scientifically quantifiable certainty. It has traditionally been stated that having penetrated the skin, most underlying tissues (except bone and cartilage) offer relatively little resistance. Similarly, it is easy to imagine how a sharp knife might easily penetrate the skin, but a less sharp knife which also penetrates thick clothing will obviously require a considerably greater amount of force.
Incised wounds which are longer than they are deep are termed ‘slash wounds’. Sometimes a cutting force follows an initial stabbing injury to produce a long ‘stab–slash’ injury. Slash wounds may result from a variety of different forms of sharp force, but knives or broken glass are usually responsible. Despite a lack of depth, slash wounds in certain sites (e.g. the neck) can pose a real threat to life. Some characteristic slash injuries are considered here.
Facial slash wounds
Slash wounds to the face commonly follow assault and are generally disfiguring rather than life threatening. Depending upon the exact location, there may be associated damage to important structures such as the parotid gland and duct and the branches of the facial nerve (supplying muscles of facial expression). Standard treatment of uncomplicated facial slash wounds comprises careful cleaning and closure of the skin with fine interrupted nylon sutures, with the latter removed at an early stage (e.g. 3 days) to be replaced with adhesive paper strips.
Neck slash wounds
Slash wounds affecting the anterior triangle of the neck may threaten life by one or more of the following mechanisms:
• Exsanguination from damage to large vessels.
• Air embolism resulting from air being sucked into damaged large veins by negative intrathoracic pressure.
• Damage to the larynx and upper airway.
Immediate treatment involves the direct application of pressure (to prevent haemorrhage) and urgent transfer to the care of a surgical team to explore under anaesthetic in theatre. Generations of junior doctors have learnt to avoid ‘gentle exploration’ of neck wounds in the Emergency Department—torrential bleeding may (re)commence and be rather tricky to stem. Slash wounds to the neck can follow assaults or be self-inflicted. The latter classically have ‘hesitation marks’ (or ‘tentative’ wounds) adjacent to a principal wound.
Wrist slash wounds
Are also typically (but not exclusively) self-inflicted, in which case they tend to run parallel on the flexor aspect of the non-dominant wrist, possibly with evidence of healing or healed old scars around the same region. Unintentional (‘accidental’) slash wounds of the wrist and forearm not infrequently follow an individual (perhaps under influence of alcohol) putting his/her arm through a pane of glass. Injury from broken glass is notorious for causing significant damage to important deep structures (nerves and tendons) and for resulting in retained foreign bodies.
Hand slash wounds
These include the classical defence injuries incurred when a victim grasps the knife being wielded by an assailant or raises the hand in defence (see [link]).
This term is usually applied to those wounds caused by sharp-edged heavy weapons such as axes and meat cleavers. Axes are very powerful weapons and it is no surprise that they hold a significant place in the history of warfare. Resulting injuries combine a sharp force injury to the skin with dramatic injury to underlying structures, including bone.
From a pathophysiological point of view, the healing process of skin wounds is divided into three stages which chronologically overlap:
• Early vascular phase: the coagulation process involves production of fibrin (interestingly, this may occur after death). An inflammatory response continues with release of cytokines and associated substances. This coincides with vascular changes of reduced tissue perfusion and enhanced vascular permeability.
• Cellular reaction: neutrophils are attracted to the wound, followed later by macrophages, which are responsible for degradation of red blood cells. Monocytes join other white blood cells in releasing factors which promote activity of fibroblasts.
• Proliferative changes: fibroblasts become very active—collagen is laid down and new blood vessels appear (the combination forming ‘granulation tissue’). The epidermis is replaced by keratinocytes.
Factors affecting wound healing
The wound healing process can be adversely affected by a number of factors which may coexist: poor generalized nutrition, reduced local blood flow and oxygenation, contamination with foreign material, and infection (the risk of infection is highly dependent upon the presence of the other factors). In general, wounds tend to heal more rapidly in younger individuals, who are more prone to exaggerated healing responses, resulting in keloid and hypertrophic scars.
Skin wounds and scarring
Skin wounds heal with characteristic scarring. In the early stages, an organized scab is replaced by a pink scar, which typically fades over weeks and months to leave a white scar. Note that wounds which are inadequately treated and which contain coloured foreign material may result in (often unsightly) discoloration (‘tattooing’). The final appearance of a scar depends upon the exact location and nature of the wound, as well as how it was treated. The best chance of a good long-term cosmetic result requires the wound to heal with its skin edges neatly apposed. Surgical skin wounds which are closed using staples or interrupted sutures (‘stitches’) often exhibit evidence of this in the form of two lines of small ‘dot scars’ adjacent and parallel on either side of the principal scar. The full thickness skin wounds which tend to heal with the best long-term appearance are linear incised wounds which penetrate at right angles to the skin surface (rather than one wound edge being undercut) and which are aligned along natural skin creases (‘Langer's lines’). The orientation of these natural skin creases is particularly appreciated by surgeons, who generally attempt to follow them when making surgical incisions.
Certain types and patterns of injury suggest that they were inflicted on an individual who was attempting to protect him/herself (Fig. 5.6). Interpretation of such injuries carries obvious medicolegal implications. Although certain injuries and patterns of injury are characteristic of having been sustained in self-defence, always be aware of other possible explanations.
Blunt force defence injuries
Ulna shaft fractures
Individuals who are being attacked with weapons such as baseball bats or truncheons typically raise their hands up in front of their faces in an attempt to protect themselves. This exposes the ulnar aspects of the forearms—direct blows may cause isolated fractures of the ulna shaft (the so called ‘nightstick injury’).
When under attack from fists and/or boots, a common response is to protect the face and if lying on the ground, to curl up into a ball. As a result, bruises and abrasions occur over the extensor aspect of the hands and forearms and also over the exposed lateral aspects of the upper arms.
Sharp force defence injuries
Palmar knife wounds
An individual who is being attacked by an assailant who is wielding a knife may attempt to grasp the blade of the knife (Fig. 5.6a). This typically results in palmar incised wounds. However, injuries to the extensor aspect of the hand and forearm may also result from defensive actions during an attack (Fig. 5.6 b & c).
Background and definitions
The term ‘intimate partner violence and abuse’ is in the process of replacing older terms such as ‘wife battering’, ‘spouse abuse’, and ‘domestic violence’. This new terminology takes into account the following facts:
• There is more to abuse than physical violence.
• Violence and abuse does not just occur between married couples, but in other relationships also.
• Men can be victims as well as women (and may be particularly embarrassed and reluctant to admit to being abused).
In the past, a combination of legal and cultural factors conspired to almost legitimize the abuse of women by their husbands. Changes in attitude have been accompanied by changes in legislation. These include the introduction of equal rights for women and the acceptance of the concept of rape within marriage.
Intimate partner violence and abuse is much more than physical injury inflicted by one partner on the other. It often involves control by one partner of the other and can involve one or more of the following elements:
• Physical injury
• Threat of physical injury (to partner and/or children/dependants)
• Sexual abuse
• Verbal abuse and isolation
• Emotional abuse
• Economic abuse.
It is acknowledged that children who are brought up with a background of intimate partner violence and abuse suffer as a result.
Prosecution—the victim and the police
Traditionally, in the UK, the police have not successfully prosecuted as many cases of intimate partner violence and abuse as they might have done. Once reunited back in the home, the injured party (traditionally the woman), retracted her statement, possibly in fear and in the belief that this was the best course of action for her own safety and that of her children and the police did not follow through a prosecution. Attitudes have now changed in that the police will consider prosecution even if the injured party no longer wishes this to occur.
Many victims fail to seek medical attention for their injuries. When they do, the reported history of injury may hide what actually happened. Deaths as part of abuse do occur, but appear to be relatively rare. Occasionally, perpetrators are killed in self-defence or in retribution for past attacks.
An increasing proportion of the general population is elderly and with advances in medical care, this demographic change seems set to continue. Amongst this group, there are an increasing number of individuals with dementia and other chronic health problems. At the same time, abuse of the elderly has emerged as a recognizable entity. Elder abuse includes domestic elder abuse (abuse by a family member or caregiver), institutional abuse (abuse in a residential facility, usually by carer), or self-abuse (self-neglect which involves refusal to accept the basic needs of food, drink, medicine, warmth, and shelter).
There are six main forms of elder abuse:
• Physical abuse
• Sexual abuse
• Psychological or emotional abuse
• Financial exploitation.
Being aware of the possibility of elder abuse is the key to recognition, otherwise appropriate action cannot be taken.
There are many different definitions of torture. In forensic practice, the most useful definition is the deliberate infliction of severe physical and/or psychological harm on an individual by a perpetrator who acts on behalf of a state. Paradoxically, the torture is usually administered by the very individual tasked with guarding and taking care of the detained person.
In medieval times, it was considered perfectly acceptable for the state to use torture in order to extract information or confessions. During the 20th century, there developed an international agreement about the unacceptability of the use of torture. Despite this, torture continues into the 21st century. Forensic practitioners may be involved in the examination and treatment of those who have been tortured and in the investigation of torture and war crimes.
Purpose of torture
Torture may be inflicted for a number of reasons, including one or more of the following:
• To obtain information
• To extract a confession
• To punish
• To spread psychological terror in a community
• To force collaboration and strengthen a regime
• Ethnic cleansing
• Personal gain and/or gratification.
Commonly employed torture methods
Torture may be classified into physical and psychological forms, although such distinctions are somewhat artificial. Commonly employed forms are:
• Beating which takes many forms. It includes telefono, where the ears are simultaneously struck, leading to tympanic membrane rupture. Falanga is beating of the soles of the foot, which can result in permanent difficulty walking.
• Suspension can cause dislocations and nerve damage.
• Asphyxiation includes wet submarino, which involves submersion of the head until unconsciousness ensues. Dry submarino uses a plastic bag over the head to achieve the same thing.
• Electrical torture typically targets the most sensitive body areas.
• Sexual torture and rape is common and takes many forms.
• Administration of drugs may weaken resistance and be used to assist with interrogation.
• Psychological torture may involve sleep deprivation, dehydration, food and water deprivation, forced nakedness, humiliation, social isolation, mock execution, prolonged interrogations, continuous noise, and/or bright lights.
When examined soon after injury, it is particularly important to carefully and accurately document injuries, as long-term evidence may diminish or disappear.
Many of the forms of torture which are used are specifically chosen to leave little or no long-term evidence. It is usually advisable for assessment, examination, and treatment of both physical injuries and psychological effects to be undertaken by respective experts in examination of torture victims. Specialist investigations, such as MRI and nerve conduction studies may be useful in the detection of soft tissue injuries and nerve damage respectively.
Forensic investigation of war crimes
Forensic pathologists and forensic physicians may play a key role in the investigation of alleged war crimes and torture on behalf of the United Nations and/or international community. Exhumation and forensic examination of bodies has been used in a number of different parts of the world, including Rwanda and the former Yugoslavia.
The head comprises the brain, surrounded by a strong supportive and protective ‘box’ (the skull), with the relatively delicate and complex bones and soft tissues of the face attached at the front. Injury to the brain is the key determinant of outcome, both in terms of survival/death and function. Fracture of the skull is, however, strongly linked with significant damage to the brain.
Incised wounds follow sharp force trauma, typically in the form of knives or broken bottles. Blunt force causes lacerations, haematomas (including those under the galea aponeurosis—subgaleal haematomas), and occasionally even degloving injuries. These last injuries may occur, for instance, when long hair is caught up in machinery.
Most scalp injuries do not in themselves threaten life, but it is worth noting that in infants significant haemorrhage can result from scalp injury. At autopsy, scalp injuries are not always easy to identify, unless it is reflected back in dissection and/or the hair is shaved (see [link]).
As with fractures elsewhere, fractures of the skull may be ‘closed’ or ‘open’ (compound) to the air. They may be compound via scalp wounds or occasionally, by communicating elsewhere (e.g. by extending into the frontal sinus or middle ear). Sometimes, only the outer table of the skull vault is breached and the inner table remains intact. Underlying a skull fracture, there may be contusions and/or lacerations to the cerebral (brain) tissue. The presence of a skull fracture significantly increases the chance of other associated intracranial injury being present or developing, most classically acute extradural haematoma occurring as a result of damage to the anterior branch of the middle meningeal artery (Fig. 5.7; see also [link]):
Running in a line, these fractures are the most common, typically affecting the vault after the application of blunt force. Fractures which damage an underlying meningeal artery cause extradural haemorrhage (see [link]). Secondary fracture lines may radiate away in a stellate (‘star shaped’) fashion. Repeated blows to an already fractured skull may result in comminution (multiple bony fragments).
Base of skull fractures
These include the devastating hinge fracture, in which a transverse fracture through the petrous temporal bone allows the two parts of the skull to open up like a hinge. Unsurprisingly, this injury is often seen at autopsy. Other skull base fractures were often not seen on X-ray (although now may be seen on CT), but may be apparent clinically in a variety of ways, including: bilateral ‘raccoon’ eyes, haemotympanum, otorrhoea, rhinorrhoea, Battles sign (bruising over the mastoid appearing late after injury).
Fractures around the foramen magnum in a ring usually reflect significant trauma, often in the form of a fall from a height or high-speed motorcycle crash (with impact to the top of the head).
Inward displacement of the inner table of the skull may reflect force applied to a relatively small area of the skull (e.g. hammer blow), or the application of extreme amounts of force to a larger area (e.g. assault by an axe). In those who survive any form of depressed fracture, epilepsy is common. Other more dramatic penetrating injuries follow gunshot injuries and explosions—fragments of skull bone may be forced into the brain. Bullets typically punch out sharp-edged defects in the outer skull table, with larger defects in the inner table.
Injury to the back of the skull (occiput), typically when an individual falls backwards, may cause a fracture of the thin orbital plates at the front of the base of the skull due to the ‘rebound’ of the brain.
Separation of normal suture lines before they have fused may occur in children as a result of brain swelling (not a fracture), but this can also occur as a fracture in older individuals.
Puppe's rule—fractures from two or more injuries
This rule was devised to assist forensic interpretation when there is more than one fracture from more than one blunt force injury. Puppe's rule is that fracture lines resulting from the second injury will not cross those from the first, thereby helping identification of which fracture occurred first. The rule has been recently applied to analysis of radial fracture lines caused by multiple bullet wounds to the head.
The brain may be injured by the primary insult (contusions, diffuse axonal injury, lacerations, and penetrating wounds) or the subsequent development of secondary effects (cerebral oedema, haematoma, infection, fits).
Bruising to the brain occurs both at the site of injury (‘coup contusion’) and at the opposite pole (‘contrecoup’), with the latter reflecting injury to the brain as it decelerates against the internal skull surface. Contusions typically affect the cortical surface, when there is associated haemorrhage into the adjacent subarachnoid space. Contusions may also occur deep in the brain tissue or as a result of massive brain swelling and movement (herniation contusions). In those who survive, cerebral contusions heal to leave cavitated scars.
Lacerations and massive crush injuries
Massive crush distortion of the brain, avulsions, and lacerations are usually unsurvivable. Although avulsions affecting the brainstem (e.g. at the pontomedullary junction) and lacerations elsewhere (e.g. corpus callosum) may follow closed head injury, most lacerations result from the effects of fracture fragments or penetrative foreign material.
Diffuse axonal injury
Diffuse axonal damage throughout the brain may follow hypoxic insult as well as serious head injury. For this reason, within the context of head injury, it is properly referred to as ‘traumatic diffuse axonal injury’. Shearing of axons (and adjacent small blood vessels) occurs during acceleration/deceleration and there is often some associated subdural haemorrhage. Many individuals do not survive, but in those who do, it can be a difficult diagnosis to make. Autopsy findings are characteristic, both macroscopically and microscopically. Macroscopically, there may be haemorrhages in the corpus callosum and basal ganglia. Microscopically, it may be difficult to identify changes if the individual has died within the first few hours after injury. Following this, injured axons swell and then when completely disrupted, form ‘retraction bulbs’, visible using standard haematoxylin and eosin staining. Histologically, staining with antibodies to detect the presence of beta-amyloid precursor protein within axons has been used to identify injury to them within 24h.
The brain is surrounded by a number of layers, collectively called the meninges, comprising (from inside out) the pia mater, arachnoid mater, and dura mater. Bleeding following trauma may occur between these various layers as outlined next.
The subarachnoid space contains cerebrospinal fluid which helps to ‘cushion’ and protect the brain. A small amount of bleeding into this space accompanies most cortical contusions. Larger amounts of haemorrhage can occur, particularly in association with serious (often unsurvivable) injuries to the base of the skull. Traumatic subarachnoid haemorrhage needs to be distinguished from non-traumatic (‘spontaneous’) bleeding from other causes (e.g. from rupture of berry aneurysms in the circle of Willis or haemorrhage from arteriovenous malformations).
Bleeding under the dura mater results from damage to bridging veins that drain into the venous sinuses. There may or may not be associated skull fractures and/or cerebral contusions. Bleeding may be acute or chronic.
Acute subdural haematomas
These may follow very minor trauma in the elderly, alcoholics, and/or those with a bleeding disorder. Individuals who are taking anticoagulants (e.g. warfarin) are at particular risk. Bleeding tends to track around the brain and when significant, can cause shift of the midline and transtentorial or uncal herniation (see later in this section).
Chronic subdural haematomas
Typically develop over days or weeks as a gradual accumulation of blood and are seen in the elderly and very young. The accumulation may result from further haemorrhage and/or possibly the osmotic effect of a slowly liquefying haematoma. There may be no history of injury available, rendering it a clinically difficult diagnosis. Attempting to establish the time of injury can be of considerable medicolegal importance at autopsy, but it is extremely difficult to do this with any degree of certainty. Haematomas which are more than a week old tend to turn brown in colour and develop a surface membrane, and start to liquefy after about 3 weeks. Sometimes the diagnosis is only made at autopsy, but when the diagnosis is made during life, it can be difficult for neurosurgeons to decide if and when to time surgical intervention.
This injury, also known as epidural haemorrhage, usually results from a skull fracture which damages a meningeal artery (e.g. the anterior branch of the middle meningeal artery) as it courses along the inner aspect of the skull. The resulting bleeding strips the dura mater away from the skull to rapidly produce a unilateral lens-shaped collection of blood which may cause midline shift and fatal compression of the brainstem. The classic presentation is of an initial injury (with or without loss of consciousness), followed by a lucid interval of several hours, before unconsciousness (and if not surgically evacuated) death ensues. Extradural haemorrhage may occur in the absence of a skull fracture, as in the case of actress Natasha Richardson (see box).
Extradural haemorrhage in a historical context
The famous actress Natasha Richardson died on 18 March 2009, aged 45 years, from an extradural haemorrhage, sustained in what appeared initially to be a relatively minor fall on a beginners' ski slope at Mont Tremblant in Quebec. For the first hour after the injury she was reported to be ‘fine’, but then deteriorated. Commentators reported this lucid interval as ‘talk and die syndrome’ and called for helmets to be used more widely during skiing.
Another well-known individual to succumb to extradural haemorrhage was Dr Robert Atkins, famous for the ‘Atkins diet’, which focuses upon the control of carbohydrate intake. He slipped and fell on his way to work, aged 72 years.
One death which some have postulated to be due to extradural haemorrhage was that of the biblical giant Goliath at the hands of David. It is generally agreed that Goliath was almost certainly suffering from visual field defects resulting from a pituitary adenoma. Speculation continues, but many now believe that original sources indicate that his temples were protected by a metal helmet and that he sustained a frontal blow which resulted in pituitary haemorrhage.
Massive swelling of part or all of the brain (and/or haemorrhage) can follow serious injury and cause a dramatic increase in intracranial pressure. This can lead to unconsciousness and death, with the final pathway often involving herniation of part of the brain down and out of its normal position, resulting in compression and pressure on vital brain centres. For example, as a result of pressure from above on one side, the midbrain may be pushed against the free edge of the tentorium, causing a characteristic (Kernohan's) notch in the cerebral peduncle. Dramatic and symmetrical pressure from above may cause the cerebellar tonsils to be forced into the foramen magnum (so called ‘coning’).
At autopsy, cerebral oedema is apparent macroscopically as there is a greatly increased weight and filling out of the normal sulci (‘valleys’), with smoothing of the gyri (‘ridges’).
Meningitis and brain abscesses
Bacterial meningitis can result from any compound skull fracture. Brain abscess is particularly associated with compound skull fractures involving penetration of the brain by foreign material or bony fragments.
Seizures may occur after head injury, either in the early period or later as a long-term problem. Penetrating brain injury, lacerations, haematomas, and contusions are risk factors.
Boxers can take a very large number of blows to the head during a career. The ‘punch drunk’ clinical presentation is of Parkinsonism, dysarthria, ataxia, and dementia (‘dementia pugilistica’). There are characteristic chronic changes within the brain: degeneration of the substantia nigra, fenestration of the septum pellucidum, scarring of the cerebellum and other parts of the brain.
Boxing death after world title fight
The potential for boxing to cause acute head injury was clearly demonstrated when US boxer Leavander Johnson died in Las Vegas in September 2005. Having failed to successfully defend his world title, he was able to leave the ring unassisted, although he visibly struggled to reach the dressing room. He collapsed shortly afterwards and died despite undergoing prompt surgery for an acute subdural haematoma. Inevitable calls to ‘ban boxing’ followed and the sport has continued to court controversy to the present time.
The bony skeleton of the face is an intricate construction of relatively delicate bones. A variety of fractures can result from injury and there are frequently medicolegal implications. Very often, injuries reflect assaults, typically taking the form of punches, kicks, or blunt injury from weapons (bottles, baseball bats). Many blunt force injuries to the face do not cause a fracture, but result in bruising to the soft tissues, with the classic example being a periorbital haematoma (‘black eye’). The soft tissues of the face are often targeted in assaults involving sharp force trauma, with scars having very significant cosmetic effects.
Le Fort facial fractures
Very serious facial fractures can follow blunt force trauma, such as high-speed car crashes (particularly when no seat belt is worn and the front seat occupant smashes into the inside of the windscreen). All result in some instability of the middle third of the face. Le Fort fractures are classified into three types:
• Le Fort I fracture is also known as a Guérin fracture. It involves the premaxilla above the apices of the teeth, rendering the upper front teeth a mobile unit.
• Le Fort II (pyramidal) fracture refers to a fracture line which extends through the maxilla (cheek bone) on both sides, meeting in the middle at the nose.
• Le Fort III fracture is a high transverse injury which reflects the face being essentially ‘sheared off’ from the face (craniofacial separation). Bleeding and/or airway compromise may be dramatic and even be the principal cause of death.
René Le Fort (1869–1951)
This French surgeon conducted a series of somewhat bizarre experiments on the skulls of cadavers. Having applied a variety of forms of blunt trauma, he carefully observed the resulting fracture patterns, from which he devised his classification of three types of midfacial fractures.
Other facial fractures
Isolated fractures to the nose, maxilla, and mandible are all relatively common injuries. They each often follow interpersonal violence (see [link]).
Cervical spine injury
Fractures and dislocations can result in complete transactions of the medulla oblongata or cervical spinal cord. Damage to the upper cord is fatal without medical intervention (the phrenic nerve supplying the diaphragm is derived from C3,4,5 spinal roots). Complete cord damage to the cord below this typically results in paralysis, loss of sensation, neurogenic shock (bradycardia and hypotension from loss of sympathetic tone to the heart), spinal shock (flaccidity and loss of tendon reflexes), priapism. There are many clinical patterns of partial spinal cord damage, perhaps the most intriguing being spinal cord injury without radiographic abnormality (SCIWORA).
Common patterns of cervical bony injury are summarized as follows:
• Jefferson fracture is a compression fracture of the ring of C1 (the atlas), often without neurological damage.
• Odontoid peg fractures are the commonest fractures to affect C2 (the axis), perhaps reflecting the slightly unusual anatomy.
• Hangman fracture affects the posterior part of C2 (both pedicles or pars interarticularis), usually from an extension mechanism, with or without distraction.
Until the mid 19th century in the UK, judicial hanging involved a short fall (a few feet), with death occurring painfully by asphyxiation. The drop distance was increased to 4–6 feet with the aim of causing a (hangman) fracture and severance of the spinal cord, resulting in rapid unconsciousness and death. The concept of a ‘measured drop’ was introduced in 1872, whereby the height of the drop was tailored to the individual. An excessive drop, however, can result in decapitation, as occurred during the execution of the Iraqi al-Tikriti in January 2007.
Thoracic and lumbar spine injuries
The most vulnerable part is the thoracolumbar junction, with injuries to the vertebral body of L1 often occurring during falls from a height. The spinal cord terminates around the level of L1, but damage below this can injure the cauda equina (collection of nerve roots). Cauda equina syndrome is characterized by bladder and bowel dysfunction.
The vertebral bodies of the lumbar spine are particularly prone to osteoporosis-related collapse. A specific severe injury to the lumbar spine is a Chance fracture—a transverse fracture through the vertebral body/disc, reflecting significant trauma, usually distraction in flexion, and often associated with intra-abdominal injury and neurological damage.
Serious chest injury may follow penetrating or blunt injury.
Penetrating chest injuries include knife stab and bullet injuries, which often result in pneumothorax. Death may follow damage to the heart or great vessels, resulting in massive haemothorax and/or cardiac tamponade. Significant defects in the chest wall may cause sucking chest wounds.
Blunt chest injuries include falls and motor vehicle collisions. Rib fractures are common and the sharp broken rib ends can cause pneumothorax and sometimes also damage to great vessels and/or the heart. Multiple rib fractures can result in a flail segment. Massive shear forces can result in rapidly fatal aortic rupture.
Isolated fractures often occur as a result of seat belt restraint in car crashes. There is sometimes associated myocardial injury.
Isolated rib fracture is a common (clinical) diagnosis (see [link]), often resulting from a low fall. Ribs typically break at the posterolateral junction and heal well within a few weeks, albeit with deformity.
Fractures of three or more ribs in two places can result in a mobile (flail) segment of chest wall. A massive flail segment including the sternum can occur when large numbers of anterior ribs are broken bilaterally. A flail segment moves in opposite direction to the rest of the chest (i.e. moving in on breathing in), adding considerably to the work of breathing.
Once a lung is punctured (e.g. by a broken rib or knife), a connection is established between the (inter)pleural space and the lung air spaces, causing the lung to collapse. Occasionally, the connection acts as a one-way valve, causing pressure to build, the lung to collapse completely, and the mediastinum to start to shift (away) from the tension pneumothorax. Mediastinal shift in a tension pneumothorax results in kinking of the great veins, thereby obstructing venous return and reducing cardiac output.
Sucking chest wound
A significant defect (hole) in the chest wall may result from impalements and gunshots. The defect, connecting with underlying pneumothorax, may offer much less resistance to air flow than the usual air passages and thereby prevent the normal inflation/deflation of the lungs.
Rapid deceleration which occurs in a very high fall or high-speed motor vehicle collision can result in transection of the thoracic aorta at the point where the mobile arch meets the fixed descending part (at the level of the ligamentum arteriosum). The traditional explanation for the injury relates to differential movement (‘shearing’) of the mobile and fixed parts, but there are alternative pathophysiological theories. One is that the clavicle and first rib move down to pinch the aorta (‘osseous pinch theory’). Whatever the exact mechanism, the result of a complete transection is usually rapidly fatal torrential haemorrhage. Occasionally, there may be contained haemorrhage, allowing survival to hospital.
Other great vessel damage
Bleeding from great blood vessels and their branches may follow direct penetration (e.g. from knife, bullet, or broken rib) or tearing. There may be a resultant massive haemothorax (collection of blood in the pleural cavity). The chance of survival depends upon the exact nature of the injury.
The death of Princess Diana
In the early hours of 31 August 1997, Princess Diana was the rear seat passenger in a Mercedes Benz car which was involved in a high-speed collision in a car which was involved in a high-speed collision in a Paris underpass. The exact sequence of events that led to the crash remains the subject of much speculation, although the combination of excessive speed and alcohol in the bloodstream of the driver, Henri Martin, has been blamed. Autopsy confirmed that the cause of Diana's death to be haemorrhage from a torn pulmonary vein. There is considerable controversy about the treatment that she received at the scene, with many observers commentating that her injuries were potentially survivable. Fingers have been pointed at the system which resulted in a delay of about 2h from the time of the crash to her reaching hospital ( http://www.wethepeople.la/diana4.htm). Others have focused upon the fact that she was not wearing a seat belt at the time of the crash.
Direct penetration into a cardiac chamber or blunt cardiac rupture can cause significant bleeding or cardiac tamponade. The latter reflects a collection of blood in the pericardial cavity, which prevents filling of the heart, thereby preventing cardiac output.
Blunt injury to the chest can cause fatal ventricular arrhythmia (commotio cordis), even when the heart is healthy. This may occur when a hard ball or kick is applied to the front of the chest in a sporting context.
The upper abdominal contents are partly protected by the lower ribs, but the lower abdomen is relatively unprotected.
Liver and splenic injury
Although protected by overlying ribs, fractures to lower ribs are associated with liver and splenic injury. The principal risk of trauma to the liver and spleen is haemorrhage, which may be torrential and rapidly life-threatening. Occasionally, there is an initially contained haematoma which ruptures and causes problems days later.
The spleen, malaria, and murder
Disease can render the spleen much more likely to bleed after injury. This fact has been used historically by assassins in the Far East, who have targeted the enlarged malarial spleen by attacking their victims with a blunt metal object called a larang. Applied with force into the left upper abdomen, the victim bleeds to death from splenic rupture, with little in the way of external marks being left on the body.
Massive force applied to the lower chest/upper abdomen may result in rupture of the diaphragm, thereby forcing intra-abdominal contents into the chest, causing amongst other things, serious respiratory compromise. On the left side, it is the stomach and spleen which are often forced upwards; on the right side, the liver.
The intestine may rupture as a result of either penetrating or blunt trauma. Perforation of any part of the intestine carries a risk of infection, particularly when diagnosis is delayed.
Severe blunt injury to the upper abdomen can cause transection of the pancreas or acute pancreatitis.
Apart from the relatively minor fractures involving the pubic rami, fractures to the pelvis carry significant risks, particularly of haemorrhage. Fractures follow a variety of different patterns, including ‘vertical shear’ (especially after high falls), ‘open book’ (typically anterior–posterior crush injury), acetabular fractures (also known as central hip dislocations, often seen in high-speed road traffic collisions). Despite the best modern treatment, including external fixation and embolization, it may prove impossible to stop haemorrhage (typically from internal iliac veins).
Most limb fractures reflect force applied to normal bones, but some (pathological) fractures occur after minimal force is applied to diseased bone (e.g. metastatic cancer, Paget's disease). Five fractures are associated with osteoporosis in the elderly: Colles' distal radius, hip, surgical neck of humerus, pubic rami, and lumbar spine compression fractures.
Fractures caused during life inevitably result in haemorrhage. In some cases, the extent of this bleeding can be life threatening. For example, it is estimated that a femoral shaft fracture is associated with approximately 1–2L of blood loss.
Most limb fractures result in two bony fragments (‘simple’), but occasionally, there is more than one fracture line, resulting in three or more bony fragments, when the fracture may be described as ‘comminuted’.
Fractures with an overlying skin wound are described as ‘compound’ (or ‘open’) and are at risk of becoming infected. Fractures with no overlying wound are termed ‘closed’. Fractures may be described as transverse, longitudinal, oblique, spiral, crush, or avulsion (‘tension’). The type of fracture may provide an indication as to how they were caused (e.g. spiral fractures reflect the application of a twisting force).
Healing occurs faster in children than adults, so, for example, a fractured distal radius in an adult is typically treated in a cast for 6 weeks, but only 3 weeks in a 10-year-old. Interestingly, fractures in young adults do not heal faster than those in the elderly. Pathophysiologically, there is an initial haematoma around the fracture, with subsequent inflammation, then osteoblasts produce new bone to form callus. Callus is visible radiologically within a few weeks of injury (2 weeks in children). It is difficult to exactly age healing fractures either radiologically or at autopsy, but it is frequently possible to conclude that there are fractures of different ages (i.e. occurring at different times)—this can be of considerable medicolegal significance, especially in suspected child abuse.
Fractures after death
Bones may be broken after death, in which case there will be a lack of vital reaction, inflammation, or evidence of healing. Note that bodies that are burned after death may sustain ‘heat fractures’ (see [link]).
Although the body can be burned by chemical or even microwave burns, most burns result from physical heat. In some instances, there is a short-lived ignition causing ‘flash burns’, whilst in others, exposure to the burning agent is more prolonged. Burns from hot liquids or steam are ‘scalds’.
Depth of burns
The extent of damage to the skin from a burn depends principally upon the temperature of the burning agent and the length of exposure.
Burns are traditionally classified according to the following system:
• First-degree burns are superficial and comprise erythema.
• Second-degree burns are ‘partial thickness’ burns, often characterized by erythema and preserved sensation. They heal without scarring.
• Third-degree burns are ‘full thickness’ burns in which all layers of the skin are burnt, sensation is absent, and healing occurs with scarring. The burnt skin (‘eschar’) often appears leathery.
• Fourth-degree burns are very severe burns which extend deeper than the skin to involve underlying tissues (e.g. fat, muscle, bone).
Deaths from burns
A previously quoted rule of thumb was that a person was likely to survive a burn if the sum of their age and the % area burnt was <100. Improvements in treatment may have changed this, but it underlines the fact that younger individuals can tolerate larger burns. Deaths from burns are associated with airway burns and extensive burns.
The upper air passages, including the pharynx and larynx, are particularly susceptible to becoming rapidly and dramatically swollen when damaged by hot gases. This swelling may result in complete airway obstruction, which without prompt medical intervention has fatal results.
Circumferential full thickness burns of the chest can prevent normal chest movement and require surgical incision (‘escharotomy’) to allow the chest wall to move properly with respiration.
Burns cause fluid loss which can be dramatic in larger burns, requiring many litres of intravenous fluid (± blood) to restore circulating volume. Specialists calculate the amount of fluid required in the initial 24h using the % area burnt and patient's weight (Muir and Barclay formula).
Individuals who survive the initial insult of a large burn are at risk of later complications, including renal failure, pneumonia, generalized sepsis, disseminated intravascular coagulation, and multiorgan failure.
In clinical practice, the extent of the body surface burnt is traditionally estimated by the ‘rule of 9's’ and use of Lund and Browder charts. The patients palm is said to be approximately 1% body surface area.
Rule of 9's: the following estimates are used in adults: head 9%; each arm 9%; each leg 18%; front of trunk 18%; back of trunk 18%; perineum 1%.
Note that in children, the percentages of body surface area are in different proportions to adults (e.g. the head covers a relatively larger areain infants, it accounts for 20% of body surface area).
Severe burns result in hair being completely burnt away and full thickness skin burns. Contractures of muscles after death result in a ‘pugilistic’ (boxer's) posture. Given that fire has been used by murderers in an attempt to destroy evidence, it is important to try to search for injuries which may have occurred before the effects of a fire. However, several effects may be erroneously attributed to injury other than heat injury:
• Splits in the skin (contractures) may appear to be knife wounds.
• The skull and other bones may fracture due to the heat.
• An ‘epidural heat haematoma’ may form after death, but be mistaken for an antemortem injury.
Timing of death
It can be important to try to establish if death occurred before or after a fire started. The presence of carbon (soot) particles in the upper airways and high levels of carboxyhaemoglobin in the blood imply that a person was alive (at least for a short time) during the fire.
In many deaths involving fire, identification of a body can be very challenging. Once facial features and fingerprints have been destroyed, reliance is placed upon comparison between X-rays and dental records.
Plane crash at Faro
On 21 February 1992, a Dutch DC-10 aircraft crashed at the Portuguese airport of Faro. A British passenger, Nicola Gunner, was initially believed to have died, but was identified 9 days later by dental records to be alive in a hospital in Rotterdam. She had sustained 65% burns and unfortunately died the following year.
Explosions may occur in industrial (e.g. factory) or domestic (e.g. gas) settings, or reflect war or terrorist activity (e.g. bombs, grenades). Incidents almost inevitably have significant forensic/legal implications and result in understandable media interest.
An intense, short-lived pressure wave lasting only a few milliseconds, expands outwards from the explosive focus. It reflects compression of air at the interface of rapidly expanding hot gases. Blast waves can be reflected from buildings. Injuries may result from the following:
• Disruption at air/tissue interfaces, especially lungs and ears, resulting in blast lung and tympanic membrane rupture respectively. Initial haemorrhage characteristic of ‘blast lung’ may be followed in those who survive initially by adult respiratory distress syndrome (ARDS).
• Shearing at tissue/tissue interfaces, causing subserous and submucosal haemorrhage.
• Implosion of gas-filled organs (resulting in gastrointestinal perforations and air embolism).
Secondary (‘fragmentation’) injuries
Objects from within a bomb (e.g. nails, nuts, bolts) may cause abrasions, bruises, puncture lacerations, and other wounds. They can also carry debris (e.g. glass, masonry) which act as secondary missiles causing injuries.
Individuals may be injured when thrown by the blast or strike large objects thrown by the blast and sustain (‘translational’) injuries. Structural collapse of buildings may also cause serious injuries.
Heat and/or fumes from the explosion may cause burns. These are typically superficial, affecting exposed skin in individuals are located close to the explosion. Severe burns usually reflect secondary fires resulting from the initial explosion. Smoke inhalation may also occur.
These include the health effects caused by materials added to bombs, including bacteria, chemicals, and radiation. Fragments of human remains (e.g. bones from a suicide bomber) may be included in this category.
It is hard to overestimate the psychological effects of being involved in a serious explosion. These effects are magnified when there are multiple casualties and/or deaths.
On the morning of 11 September 2001, four passenger aeroplanes were taken over by hijackers with the intention of undertaking coordinated suicide attacks on buildings with international significance. The hijackers used knives to kill cabin crew and then fly towards their targets. All of the planes crashed, killing everyone on board and several thousand on the ground:
• The 110th floor North Tower of the World Trade Center in New York was struck first (at 0846 hours), caught fire, and collapsed within 2h.
• The South Tower was struck at 0903 hours, collapsing within an hour.
• The third target was the Pentagon, into which a passenger jet crashed at 0937 hours.
• The fourth hijacked plane crashed into a field in Pennsylvania at 1003 hours after passengers attempted to wrestle control of the aircraft back from the hijackers.
The attacks on the twin towers took the heaviest death toll. Most of the individuals died when the towers collapsed, although many died at the time of the initial impact and some later due to the effects of fire, with a number falling or even jumping to their deaths in an effort to escape the fire and smoke.
The short and long-term effects of the ‘9/11’ attacks were considerable—the impacts were felt worldwide, in economic, social, and political form.
For forensic experts, the challenge of trying to identify those who died in the collapse of the twin towers was enormous. After a vast investigation, an impressive 57% of the victims were positively identified using a combination of DNA, dental records, and jewellery. However, this did leave >1000 victims who remain to be identified.
Forensic investigations after a suspected terrorist or other explosion will initially take second place to treating victims.
Number of fatalities
When deaths occur in any explosion, the first job is to try to establish how many people have died and exactly who they are. On those occasions when there are numerous victims with very serious injuries, it can be a considerable challenge to ascertain the number of individuals who have been killed. The process may involve a painstaking search and close examination of the retrieved body parts.
The easiest means of identification is visual confirmation of a person's identity by a relative, although corroboration by a second individual is a sensible precaution. For some casualties, visual identification may be impossible due to the extreme nature of the injuries sustained, so reliance may need to be placed upon other means, including a combination of the following:
• Dental records
• DNA (e.g. a blood sample).
Cause of death
The presence of serious injuries in the context of an explosion might lead to the simple conclusion that the explosion caused death. However, it is very important to consider the possibility that death may have occurred in another way prior to the explosion. Analysis of the injuries on each individual will help to provide an idea of the relative positions at the time of the explosion. It can be helpful to X-ray bodies prior to autopsy in order to establish where foreign material (shrapnel etc.) is embedded.
The use of suicide as a way of killing the enemy is not new, as underlined by Japanese (‘kamikaze’) pilots targeting allied warships in World War II. In more recent times, suicide bombers have been used against both civilian and military targets. The methods employed have varied, ranging from individuals detonating devices which are strapped to their bodies when standing close to their targets, to the use of vehicles or (as in the attacks of 11 September 2001, see [link]) aeroplanes. In most instances, the suicide bomber sustains overwhelming injuries, which may be so severe that little of the body is recovered. Occasionally, as in the case of the Exeter bomber in 2008, injuries may be relatively minor.
Four suicide bombers targeted London in the most deadly bomb attack on the city since World War II, in what subsequently became known as the ‘7/7’ bombings. Three explosions occurred on the London Underground (two on the Circle line, one on the Piccadilly) and one on the top deck of a double-decker bus in Tavistock Square. In addition to the four bombers, 52 people died in the attacks. The bombers were British Muslims who appear to have been motivated to attack other members of the British public due to Britains involvement in the war in Iraq.
Types of weapons
Also known as ‘smoothbore weapons’, shotguns fire a bundle of lead pellets (shot) which travel down a smooth metal tube (barrel) to emerge via the muzzle. Some weapons have a double barrel, with one barrel employing a distinct taper (choke), which affects the spread of pellets. The barrels may be shortened in order to render them less conspicuous in armed crime (‘sawn-off shotgun’).
The long barrel of a standard rifle contains spiral grooves (‘rifles’) which impart a rotation on the bullet with the intention of providing some stability as it travels through the air, thereby increasing accuracy and range. The inner aspects of the barrel between the grooves are known as the ‘lands’. Minor imperfections in the rifling causes characteristic imprints on the bullet as it passes by, resulting in marks on the bullet which can be as specific as fingerprints and allow a ‘match’ to be made between a bullet and the weapon that fired it. The calibre of a weapon is usually defined as the inner diameter of the barrel. Military weapons are ‘self-loading’ (gun continues to fire each time the trigger is pulled) or ‘automatic’ (the weapon continues to fire once the trigger is held). Bullets which travel at >300m/s are regarded as ‘high-velocity’ missiles.
This typically comprises the bullet, attached to the cartridge case, with gunpowder and primer between. When the gun's firing pin strikes the base of the cartridge, the primer is detonated and thence the gunpowder. Detonation of the gunpowder forces the bullet down the barrel at speed. At the same time, some of the gunpowder (and burnt gunpowder in the form of soot) emerges from the muzzle, causing characteristic tattooing of the skin at close range (see [link]).
• Bullets come in various materials, shapes, and sizes.
• Shotgun cartridges (shells) contain numerous lead pellets.
Anatomy of guns (Fig. 5.9)
Entry wounds from rifles
Close contact between the muzzle of the weapon and the skin results in characteristic contact wounds, which depend upon the type of weapon, the part of the body injured, and the angle of contact. Firm contact forces the bullet and associated hot gases under the skin and leaves a muzzle imprint on the skin. Depending upon the part of the body affected, in some instances, the skin may split open at this entry point.
Loose contact wounds typically result in a dark ring of soot. Note that in close and near contact wounds, material from the target (hair, skin, etc.) may ‘rebound’ (or, more properly, be sucked back) into the muzzle of the weapon.
Near contact wounds occur when the muzzle is close, but is not in direct contact with the skin. There is no significant powder tattooing of the skin.
Intermediate range wounds result in gunpowder tattooing of the skin, which becomes less apparent and spread out over a wider area as the distance between the weapon and skin increases.
Distant gunshot wounds do not exhibit any associated tattooing or soot staining of the skin, a situation which typically occurs at distances of >1m (although it does vary according to the nature of the weapon). The size of the (entry) hole does not equate to the size of the bullet, as the skin tends to become stretched just before the bullet pierces it, so that the wound is typically smaller than the diameter of the bullet. Most entry wounds are circular or oval, depending upon the angle at which they strike the skin. The skin around the entry wound is discoloured as an ‘abrasion collar’, which reflects the heat and friction created as the bullet passes through the skin.
It is important to try to distinguish entry from exit wounds. This task is not usually very difficult. Exit wounds tend to be larger and more irregular than entry wounds, as the bullet is likely to be deformed and travelling in less predictable fashion as it exits the body. There is usually no abrasion collar, although this can occur when the skin at the point of exit is pressed against a hard surface—the resulting wound is referred to as a ‘shored wound’.
It is standard practice to X-ray the body of anyone who is found dead after gunshot injury, in order to identify the number and position of bullets prior to autopsy. Probes may be helpful in demonstrating the paths taken by bullets.
Gunshot wounds are regarded as medium- and high-energy injuries. As the bullet travels through the body tissues, it crushes tissues, stretches adjacent tissue, and creates a large temporary cavity, which can cause widespread damage. This damage is much greater with high-energy weapons, where the vacuum effect of the temporary cavity can suck clothing and other foreign material into the wound. Bullets behave differently according to the tissues through which they pass:
• Bone may shatter as it is struck by a bullet, resulting in numerous fragments which cause damage as secondary missiles.
• Head injuries from gunshot can be devastating, particularly when high-energy weapons are used, when the skull can ‘explode’. As a bullet passes through the skull bone, the internal defect is usually larger than the external one, giving a ‘cratered’ (or ‘funnelled’) appearance at autopsy. Bullets may ricochet inside the skull.
• Chest injuries are often fatal, due to overwhelming damage to the heart and large vessels. Bullets which pass through the lungs produce an inevitable pneumothorax (see [link]), but due to the less dense nature of the lungs, less energy tends to be transferred to the tissues.
• Abdominal injury from gunshot injury can also be devastating, depending upon the structures damaged. Damage to the bowel adds considerably to the potential for infection.
The shooting of John F. Kennedy
Perhaps the best-known gunshot wounds in history were those inflicted on the US President, John F. Kennedy. The 46-year-old suffered fatal gunshot wounds whilst travelling in a motorcade in Texas on 22 November 1963. An autopsy performed at Bethesda Naval Hospital concluded that he sustained two gunshot wounds: one (the ‘fatal’ injury) to the back of his head and the other to his upper back. A man named Lee Harvey Oswald was arrested a little more than an hour later on suspicion of having been responsible for the assassination, but he was himself shot and killed before he could stand trial. An official report at the time concluded that Oswald was responsible, but this did not stop a myriad of conspiracy theories. Many of these theories persist to this day, perhaps being partly fuelled by apparent discrepancies in previous accounts and doubt being cast upon the validity of the autopsy findings.
Shotguns fire multiple lead pellets (‘shot’) via a smoothbored barrel. The pellets initially emerge from the muzzle grouped closely together, but gradually spread out and disperse as they travel away from the weapon. The extent to which the pellets spread out varies from weapon to weapon and depends upon the taper (‘choke’) of the barrel, as well as the type of ammunition which was used. In addition to the pellets emerging from the muzzle, so do wads (typically made of cardboard or felt), powder, and soot, which cause characteristic marks when the shotgun is discharged at close range.
Shotgun entry wounds (Fig. 5.10)
Contact wounds produce a skin wound of approximately the size of the internal diameter of the barrel, although in certain circumstances, larger wounds can occur (especially over the skull, when overlying skin can be torn away). As with rifled injuries, there may be a muzzle imprint. Sometimes, carbon monoxide in the hot discharge gases may bind to myoglobin and haemoglobin in the wound, causing pink/cherry red discoloration.
Near contact (close range) shotgun wounds of <15cm are circular defects, with soot staining and powder tattooing of adjacent skin, which may be burnt (and have burnt hairs)—see Fig. 5.10(f). The wad is usually to be found buried in the wound.
Intermediate range wounds comprise less perfect circular skin defects, perhaps with some pellets making individual (satellite) holes outside this (reflecting minor dispersal of the pellets). Usually with the wad is buried in the wound. The skin edges tend only to be blackened if the range is within 30cm and similarly, skin tattooing occurs only for distances less than 1m.
Longer range shotgun wounds exhibit a wider spread of pellets (Fig. 5.10(a)), although a central defect may still be seen at ranges <10m (Fig. 5.10(b)). Determination of the exact range may require test firing of the weapon using identical ammunition.
Direction of shotgun injury
When a shotgun is discharged at right angles to the skin, the resulting central defect will be circular, but will become an ellipse when the weapon is applied tangentially. In the case of the latter, one edge of the wound will be undercut. It can be difficult to trace the exact paths of shotgun pellets, especially when there is deflection/ricochet off other structure, notably bone.
Shotgun exit wounds
Because of the relatively small size and velocity of the pellets, they rarely completely penetrate the adult trunk, but can penetrate the limbs and neck. When fired in suicidal fashion through the open mouth, a shotgun is capable of a devastating destructive lesion in which much of the brain is expelled from a large defect in the skull.