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The neck 

The neck
Chapter:
The neck
Author(s):

Rogan Corbridge

and Nicholas Steventon

DOI:
10.1093/med/9780199550791.003.14
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Anatomy of the neck

Surface anatomy

Many of the important structures in the neck can be seen or felt on examination. These are:

  • The mastoid process (a)

  • The clavicular heads (b)

  • The sternomastoid muscle (c)

  • Trachea (d)

  • Cricoid cartilage (e)

  • Cricothyroid membrane (f)

  • Thyroid prominence (g)

  • Hyoid bone (h)

  • Carotid bifurcation (i)

  • Thyroid gland (j)

  • Parotid gland (k)

  • Submandibular gland (l)

  • Jugulodigastric lymph node (m)

Use Fig. 14.1 to identify the above structures on yourself. It is particularly important to quickly identify the cricothyroid membrane in order to be able to perform an emergency cricothyroidotomy (The neck see ‘Cricothyroidotomy’, p. [link]).

Fig. 14.1 Surface anatomy of the neck.

Fig. 14.1
Surface anatomy of the neck.

Triangles of the neck

The anterior and posterior triangles of the neck are often referred to in clinical practice and are useful descriptive terms. These triangles may be subdivided as shown in Fig. 14.2a, but the usefulness of the subdivisions is questionable. (This is not to say that an enthusiastic examiner would not be prepared to quiz you on them!)

Deep anatomy

The neck is divided into anatomical compartments by strong fascial layers (The neck see Fig. 14.2b).

Fig. 14.2b Fascial layers and spaces of the neck.

Fig. 14.2b
Fascial layers and spaces of the neck.

  • The posterior compartment—contains the skeletal muscles of the cervical spine.

  • The anterior compartment—has additional fascial envelopes containing these important structures:

    • The pretracheal fascia encloses the thyroid gland and binds it to the trachea

    • The carotid sheath encloses the carotid, internal jugular, and vagus nerve

Between these fascial planes lie the parapharyngeal space and the retropharyngeal space. These spaces are clinically relevant because they may become involved in and allow the spread of deep-seated infections or malignancy.

Lymph node levels

The classification of lymph node levels in the neck are commonly referred to in clinical practice and it is important to have an understanding of them. (The neck See Fig. 14.3.)

Fig. 14.3 Lymph node levels in the neck.

Fig. 14.3
Lymph node levels in the neck.

Most lymph drainage from the aerodigestive tract is through the deep cervical chain which runs along the internal jugular vein deep to the sternomastoid muscle. It has been discovered that particular anatomical sites drain reliably to particular groups of lymph nodes.

A nodal level system has been devised to simplify the discussion of lymph nodes and to ensure that we are all talking the same language. Essentially this is a naming system which gives a number or level to groups of lymph nodes in a particular area. (The neck See Fig. 14.3 for a diagram of the lymph node levels in the neck.)

This nodal level system is of particular importance when considering the lymphatic spread of ENT cancers. The first group of nodes which a cancer involves is called the ‘first echelon nodal level’. For example, the first echelon nodes for tonsil cancer are level 3, from here other nodal levels may be affected, usually levels 2 and 4.

Cancers in other sites may metastasize in different patterns, for example the first echelon nodes from nasopharyngeal cancer tends to be level 5. This concept and model has led to the development of selective neck dissections, e.g. supra-oma-hyoid neck dissections (The neck see ‘Neoplastic lymphadenopathy’, p. [link]).

Investigation of neck lumps

Neck lumps are common. All patients with a neck lump must have an ENT examination to exclude a malignancy.

A full history should be taken, including duration, change in size, smoking history, pain (including referred otalgia), and any intercurrent illness.

A neck lump should be thoroughly examined and the following aspects noted: site, size, shape, texture (smooth or lobulated), position (midline or central), solid or cystic, single or multiple, tender, attached to deep structures, movement on swallowing, movement on tongue protrusion, pulsatile (The neck see ‘A lump in the neck’, p. [link]).

In addition to the above, a full ENT examination should be performed.

Investigations

  • Fine needle aspiration cytology (FNAC)—is the single most important diagnostic test. It is like a blood test but involves taking cells from the lump rather than blood from a vein. There is no danger of seeding malignant cells if the appropriate method is used (The neck see ‘How to perform an FNAC’, p. [link]).

  • Blood tests—Where the history suggests an inflammatory mass consider:

    • FBC

    • ESR/CRP

    • Paul–Bunnell/Monospot/IM screen

    • Toxoplasmasis screen

    • HIV test

  • Biopsy—may be needed if a diagnosis cannot be made. Wherever possible this should be excisional rather than incisional. All but the most trivial neck masses should be biopsied under general anaesthetic.

  • Endoscopy—cancers of the silent sites of the head and neck may give little or no symptoms themselves but may metastasize to the neck, presenting as a neck mass. Examination of these sites is vital, usually under general anaesthetic, i.e. a panendoscopy, which looks at all the food and breathing passages. The silent sites are:

    • nasopharynx

    • tongue base

    • tonsil

    • vallecula

    • piriform fossa

    • postcricoid region

  • Radiology

    • CXR—for malignancy, TB, HIV.

    • Ultrasound scan (USS)—for thyroid, salivary glands. This test is may be useful in children as it is non-invasive and easy, and it can distinguish between a solid or a cystic lump.

    • Spiral CT—rapid acquisition is useful for mobile structures like the larynx and for those patients who find lying flat difficult.

    • MRI—provides excellent soft tissue definition but is degraded by patient movement.

Key point—neck lumps

  • FNAC (± USS) is the investigation of choice.

  • In expert hands FNAC >80% accurate.

  • If the FNAC is non-diagnostic repeat only once and consider excision biopsy and panendoscopy.

Congenital neck remnants

Thyroglossal cysts and fistulae

The thyroid gland develops at the base of the tongue and descends through the tissues of the neck to its final position overlying the trachea. It leaves a tract which runs from the foramen caecum of the tongue to the thyroid gland. This tract curves around the body of the hyoid bone. Thyroglossal cysts and fistulae arise from congenital abnormalities of this process. They are common in teenagers and in young adults.

Signs and symptoms

These may present as a midline, a paramedian swelling, or a discharging sinus. The cyst will rise on tongue protrusion, due to their attachment to the tongue base. (The neck See Fig. 14.4 opposite, and Fig. 15.1, p. [link].)

Fig. 14.4 Thyroglossal cysts rise on tongue protrusion.

Fig. 14.4
Thyroglossal cysts rise on tongue protrusion.

Treatment

Before surgical excision of the lesion, ensure that there is a normal functioning thyroid gland in its usual position in the neck. Surgical excision, known as Sistrunk’s operation, involves removing the lesion plus that tissue block between the lesion and the hyoid, plus the mid portion of the hyoid bone and any associated tract passing to the foramen caecum of the tongue. There is a risk of recurrence if less radical procedures are used.

Branchial cysts

These common, benign neck cysts usually appear before the age of 30. They occur at the junction of the upper third and lower two-thirds of the sternomastoid muscle. They often arise following a URTI. They are thought to be caused by degeneration of epithelial inclusions in a lymph node.

Branchial cysts are usually asymptomatic, but they may become painful due to a secondary infection. An FNAC test yields a pus-like aspirate that is rich in cholesterol crystals. The treatment is surgical excision.

In patients over 50 years old, branchial cysts may be confused with metastatic deposits of SCC, which have undergone cystic degeneration. In this group, an FNAC suggesting a branchial cyst should be treated with suspicion.

Branchial fistulae

These arise as a defect in the fusion of branchial clefts. They present as a discharging skin sinus somewhere along the anterior border of the sternomastoid. There is an associated tract, which runs from the skin to the oropharynx, usually ending at the anterior pillar of the tonsil. This tract will pass between the external and internal carotid arteries, in close proximity to cranial nerves X, XI, and XII. Surgical excision of the complete tract, including the tonsil, may be necessary.

Dermoid cysts

These cysts lie anywhere between the chin and the suprasternal notch. They arise from defects in fusion of the midline and are an example of ‘inclusion cysts’. They present as painless midline swellings and do not move on swallowing or tongue protrusion. Treatment is via surgical excision.

Cystic hygroma

These are rare, benign lymphangiomas found in neonates and infants. They insinuate themselves between the tissues of the neck and may reach a massive size. They may cause compressive airway symptoms.

Treatment involves securing the airway where necessary, surgical excision can be staged, or injection with sclerosant.

Key point

Remember: Branchial cysts are unusual in middle-aged patients so beware! Metastatic SCC can mimic a branchial cyst on FNAC and imaging and the primary cancer (usually in found in the tonsil) may be completely asymptomatic. Therefore, list for excision as a matter of priority and include a panendoscopy at the same time.

Neck infections

Parapharyngeal abscess

This is a deep-seated infection of the parapharyngeal space (The neck see ‘Anatomy of the neck’, p. [link]). It often results from a primary infection in the tonsil, or is an extension from a parapharyngeal abscess (or quinsy) (The neck see ‘Tonsillitis’, p. [link]). It is more common in children than in adults.

Signs and symptoms

These include pyrexia, neck swelling deep to the sternomastoid muscle and a patient who seems unwell. There may be trismus, or a reduced range of neck movements. The tonsil and the lateral pharyngeal wall may be pushed medially. Airway compromise is a late and ominous sign.

If the diagnosis is in doubt, a CT scan will often distinguish between lymphadenitis and an abscess.

Treatment

This will involve a high dose of IV broad-spectrum antibiotics (co-amoxiclav), in addition to surgical drainage via a lateral neck approach.

Retropharyngeal abscess

This is a very rare infection of the retropharyngeal space. It is much more common in children and infants than in adults.

Signs and symptoms

An unwell patient, with pyrexia, often with preceding URTI or swallowing difficulty. There may be shortness of breath or stridor, or torticollis—due to prevertebral muscle irritation.

Treatment

A high dose of IV broad-spectrum antibiotics (co-amoxiclav). Where necessary, the airway will be secured and surgical incision and drainage may be performed via the mouth.

Ludwig’s angina

This is a rare infection of the submandibular space, it usually occurs as a result of dental infection. It is more common in adults than in children.

Signs and symptoms

These include pyrexia, drooling, trismus, airway compromise due to backward displacement of the tongue. There may be firm thickening of the tissues of the floor of mouth—best appreciated on bimanual palpation.

Treatment

High doses of IV broad-spectrum antibiotics (co-amoxiclav). Secure the airway (try a nasopharyngeal airway first since this will often suffice, but were necessary consider a tracheostomy). Surgical incision is often unsatisfying since little pus may drain away.

Lymph node enlargement

  • The majority of neck nodes in children are benign.

  • The majority of neck nodes in adults are malignant.

  • Neck nodes may be involved secondarily in an infection of any part of the ENT systems.

The neck See ‘Lymph node levels’, p. [link].

Infective lymphadenopathy

This secondary lymphadenopathy is extremely common in children. An example is jugulodigastric node enlargement during or following tonsillitis. A single node or a group of nodes may be enlarged. There may be tenderness and symptoms related to the primary infection.

Specific infections presenting with lymph node enlargement (primary lymphadenopathy) include:

  • Glandular fever

  • TB

  • Toxoplasmosis

  • Brucellosis

  • Cat-scratch fever

  • HIV

The diagnosis in these cases will often be made following the appropriate screening blood test and CXR. FNAC and even excision biopsy may be needed to exclude malignancy.

Neoplastic lymphadenopathy

Lymphoma

This is a primary malignant tumour of the lymphatic tissues.

Signs and symptoms

Multiple nodes of a rubbery consistency. The patient may or may not experience night sweats, weight loss, axillary or groin nodes, and lethargy.

Investigations

FNAC may be suspicious, but an excision biopsy is often required to confirm the diagnosis and allow for subtyping. A CXR and/or a chest CT scan may be done, or, for staging, a CT scan of the abdomen or pelvis. Bone marrow may be needed for staging.

Treatment

May involve chemotherapy and/or radiotherapy. The patient may need a lymphoma MDT review.

Squamous cell carcinoma

This is a primary mucocutaneous malignancy which commonly spreads to local lymph nodes. It can affect single or multiple nodes.

Signs and symptoms

The patient may have ENT-related symptoms such as a sore throat, a hoarse voice, or otalgia. The nodes may have a firm or hard consistency. The patient may have a history of smoking.

Investigations

These may include FNAC, ENT examination looking for ENT primary carcinoma, a CT or MRI scan of the neck, a CT scan of the chest and/or CXR (metastases), a liver USS (metastases), a panendoscopy, and biopsy.

Where no ENT primary is seen on examination, a rigorous search should be made for a silent tumour. This will usually involve imaging as above with ipsilateral tonsillectomy, biopsy of the tongue base, postnasal space, and piriform fossa as a minimum. (The neck See ‘Investigation of neck lumps (Endoscopy)’, p. [link].)

Remember: all patients with a neck lump MUST have an ENT examination, including laryngoscopy and endoscopy of the postnasal space. This is essential to exclude a small and asymptomatic malignant primary tumour.
REFER NECK LUMPS TO ENT.

Treatment

This depends on the stage, the size, and the site of the primary (The neck see also Box 14.1). Options for treatment include:

Radiotherapy—involves 4–6 weeks of daily treatment with a total dose of 50–60Gy.

Radical neck dissection—involves removing the affected nodes as well as all the other nodal groups and lymph-bearing structures on that side of the neck. This includes the lymph nodes at level 1, 2, 3, 4, and 5, the internal jugular vein (IJV), the sternomastoid muscle, and the accessory nerve.

Modified radical neck dissection—takes all the nodal levels (1, 2, 3, 4, 5) but preserves one or all of the IJV, the sternomastoid, and the accessory nerve.

Selective neck dissection—instead of all the nodal groups being removed, those groups thought to be at most risk are selectively dissected and removed. All other structures are preserved.

Neck hernias

Pharyngeal pouch

The neck See Chapter 13, p. [link].

Laryngocoele

This is caused by expansion of the saccule of the larynx. The saccule is a blind-ending sac arising from the anterior end of the laryngeal ventricle (The neck see Fig. 12.3, p. [link]). A laryngocoele is an air-filled herniation of this structure. This can expand, and either remains within the laryngeal framework (internal laryngocoele), or part of it may extend outside the larynx (external laryngocoele). It escapes through a point of weakness in the thyrohyoid membrane.

There is a rare association with a laryngeal cancer of the saccule, and all patients should have this area examined and biopsied.

There is little evidence to support the supposition that this condition is more frequent in trumpet players and glass-blowers.

Signs and symptoms

  • Lump in the neck which may vary in size

  • Hoarseness

  • A feeling of something in the throat FOSIT

  • Swallowing difficulties

  • Airway problems

If the laryngocoele becomes infected and full of pus (laryngopyocoele) then it may rapidly increase in size and cause additional pain.