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THE HEAD AND NECK
(APPLIED AND CLINICAL ANATOMY)

The surface anatomy of the neck
In the midline, from above down, can be felt:
1
...
The notch of the thyroid cartilage—at the level
of C4;
3
...
The cricoid cartilage—terminating in the trachea
at C6;
5
...
The suprasternal notch
...
:
Note that the lower border of the cricoid is an important level in
the neck; it corresponds not only to the level of the 6th cervical
vertebra but also to:

1
...


The junction of the pharynx with the oesophagus;

3
...


The level at which the vertebral artery enters the transverse
foramen in the 6th cervical vertebra;

5
...


The level of the middle cervical sympathetic ganglion;

7
...

The common carotid artery pulse can be felt by pressing
backwards against the long anterior tubercle of the
transverse process of C6
...

This includes:
1
...

2
...

• The prevertebral fascia passes across the vertebrae and prevertebral
muscles behind the oesophagus, the pharynx and the great vessels
• The pretracheal fascia encloses the visceral compartment of the neck
...


Triangles of the neck:

• In infections or cancer from any of the areas of drainage of the submental
nodes, especially the tip of tongue and lip, the first nodes to be involved are
submental nodes
...

• A discharging sinus on the point of the chin often results from an abscess of a
mandibular incisor tooth
...


Clinical anatomy:
1
...
Such a sinus
can be dissected from the midline of
the neck along the front of the
hyoid, then backwards through the
muscles of the tongue to the
foramen caecum
...


• 2
...
A carcinoma of the thyroid invades its neighbors rather than
displacing them—eroding into trachea or oesophagus, surrounding the
carotid sheath and occasionally causing severe haemorrhage from them
...
Horner's syndrome results from damage to the cervical
sympathetic chain
...


• The Spaces around the pretracheal fascia provides for spread of
infection
...

Prevertebral Fascia:
• The retropharyngeal space between pharynx and pre-vertebral
fascia is clinically important because it frequently becomes infected
secondary to upper respiratory tract infections in childhood
...
In adults such infections are usually
secondary to tuberculosis of the cervical vertebral column
...
This thyroid
capsule is much denser in front
than behind and the enlarging
gland therefore tends to push
backwards, burying itself round the
sides and even the back of the
trachea and oesophagus
...
Above, the
pretracheal fascia blends with the
larynx, accounting for the upward
movement of the thyroid gland
with each act of swallowing
...
This lies in the line of the
natural skin folds of the neck
...
If more room is required in
the case of a large goitre, the strap muscles are divided; this is carried out at
their upper extremity because their nerve supply (the ansa hypoglossi)
enters the lower part of the muscles and is hence preserved
...
The
thyroid is then mobilized and its vessels ligated
...


Relationship of recurrent laryngeal nerve to
thyroid gland
The relationship of the
recurrent laryngeal
nerve to the thyroid gland
and the inferior
thyroid artery
...
In
these diagrams the lateral
lobe of the thyroid is pulled
forwards, as it would be in
a thyroidectomy

Congenital deformities of the face, lips and
palate

Development
Around the primitive mouth, or stomodaeum, develop the following:
1
...
Two
olfactory pits develop in it and rupture into the pharynx to form the
nostrils
...
The maxillary processes on each side, which fuse with the frontonasal
process and become the cheeks, upper lip (exclusive of the philtrum),
upper jaw and palate (apart from the premaxilla);
3
...


Congenital deformities
Abnormalities of this complex fusion process are numerous and constitute one of
the commonest groups of congenital anomalies
...
Indeed, it is good clinical practice to search a patient with
any congenital defect for others
...

1
...

2
...
e
...
Much more commonly, the cleft is on
one or both sides of the philtrum, occurring as failure of fusion of the maxillary
and frontonasal processes
...
There may be an associated cleft palate
...
Cleft lower lip—occurs very rarely but
may be associated with a cleft tongue and
cleft mandible
...
Cleft palate is a failure of fusion of the
segments of the palate
...


FLOOR OF THE MOUTH
Ludwig’s angina
...
The infection spreads above the
mylohyoid; oedema forces the tongue
upwards and the mylohyoid itself is pushed
downwards so that there is swelling both
below the chin and within the mouth
...
Drainage is carried out by a deep
incision below the mandible which must
divide the mylohyoid muscle
...

From above downwards, it is made up of
three portions :
1
...
The oropharynx—lying behind the
anterior pillars of the fauces;
3
...


The nasopharynx
1
...
When chronically inflamed they
may all but fill the nasopharynx, causing mouth-breathing and also, by
blocking the auditory tube, deafness and middle ear infection
...
The Eustachian tube provides a ready pathway of sepsis from the
pharynx to the middle ear and accounts for the frequency with which
otitis media complicates infections of the throat
...
The middle ear can be intubated through a catheter passed into the
Eustachian tube
...
Its curved tip is then rotated laterally
so that it lies in the pharyngeal recess; it is then withdrawn over the
Eustachian cushion to slip into the orifice of the auditory tube
...
It is
drained by an incision in the most prominent part of the abscess where
softening can be felt
...
In dissection, an incision is
made in the mucosa of the anterior pillar immediately in front of the tonsil;
the gland is then freed by blunt dissection until it remains attached only by
its pedicle of vessels near its lower pole
...


Pharyngeal pouch:
The inferior constrictor muscle is made
up of an upper oblique and a lower
transverse part, the former arising from
the side of the thyroid cartilage (the
thyropharyngeus) and the latter from
the cricoid (the cricopharyngeus)
...
The mucosa and submucosa
of the pharynx may bulge through this
weak area to form a pharyngeal pouch
possibly as a result of muscle
incoordination or of spasm of the
cricopharyngeus
...


The salivary glands:
1
...

2
...
In differentiating between an enlarged submandibular gland and a
mass of submandibular lymph nodes, one remembers that the
gland lies not only below the mandible but also extends into the
floor of the mouth; it can therefore be palpated bimanually
between a finger in the mouth and a finger below the angle of the
jaw
...


The major arteries and veins of
the head and neck
1
...

Vascular changes in the arm associated with a cervical rib are
probably due to peripheral emboli thrown off from thrombi
forming on the walls of the compressed subclavian artery
...

An aneurysm of the subclavian artery is not rare; it
never involves the thoracic part of the subclavian and
its site of election is the third part of the artery
...
Oedema of the
arm may result in compression of the subclavian vein
...
A carotico-cavernous arteriovenous
fistula results with pulsating exophthalmos, a loud bruit
easily heard over the eye and, again, ophthalmoplegia
and marked orbital and conjunctival oedema due to
the venous pressure within the sinus being raised to
arterial level
...
A
characteristic picture results—blockage of the venous drainage of the orbit
causes oedema of the conjunctiva and eyelids and marked exophthalmos,
which demonstrates transmitted pulsations from the internal carotid artery
...

Examination of the fundus shows papilloedema, venous engorgement and
retinal haemorrhages, all resulting from the acutely obstructed venous
drainage
...
S
...
drainage into the
latter and therefore the development of a hydrocephalus—
this syndrome of raised C
...
F
...
It is also possible for sagittal sinus thrombosis
to follow infections of the skull, nose, face or scalp because
of its diploic and emissary vein connections; if there were no
emissary veins, infections of the face and scalp would never
have been able to spread easily

The skull

Anterior view

Parietal foramina

Bregma

Lambda

lateral aspect

Caput sucedanium

Fractures of the skull:
The base of the skull is more fragile than the vault, and is thus
commonly involved by such fractures
...
localized severe
injury, in the adult, may produce a depressed comminuted
fracture; the infant’s skull is much more elastic and a similar
injury here will result in a ‘pond’ depressed fracture
...

In such cases C
...
F
...

Fractures involving the roof of the orbit are frequently associated with
blood tracking forward beneath the conjunctiva (subconjunctival
haemorrhage)
...

A ‘black eye’ is not necessarily indicative of an anterior fossa fracture; it
may be produced also by direct contusion of the soft tissues or by
blood tracking down deep to the aponeurotic layer of the scalp
...

Fractures of the middle fossa may produce bleeding into the mouth if the
sphenoid bone is involved, bleeding or C
...
F
...
Aural bleeding may, of course, be produced by direct
injury to the ear—for example, rupture of the drum—without necessarily
implying a skull fracture
...

Posterior fossa fractures are occasionally accompanied by cranial nerve
involvement
...


Intracranial Hemorrhage:
• In a subdural hematoma, blood collects
between the layers of tissue that
surround the brain
...
In a subdural
hematoma, bleeding occurs between the
dura and the next layer, the arachnoid
...
As blood accumulates,
however, pressure on the brain
increases
...
If pressure inside the skull
rises to very high level, a subdural
hematoma can lead to unconsciousness
and death
...
It can be
acute or chronic:
In acute the sudden blow to the head tears blood vessels that run along the
surface of the brain
...
A relatively
minor head injury can cause subdural hematoma in people with a bleeding
tendency
...
Symptoms may not be
apparent for several days or weeks
...


Symptoms of subdural hematoma can
include:
• Headache
• Confusion
• Change in behavior
• Dizziness
• Nausea and vomiting
• Lethargy or excessive drowsiness
• Weakness
• Apathy
• Seizures

Investigation
• Head imaging, usually with computed tomography
(CT) or magnetic resonance imaging (MRI scan)
...

• Rarely, angiography may be used to diagnose subdural
hematoma
...


Epidural hematoma
• Also called an extradural hematoma, this type occurs when a
blood vessel — usually an artery — ruptures between the
outer surface of the dura mater and the skull
...

• Some people with this type of injury remain conscious, but
most become drowsy or comatose from the moment of
trauma
...
After a head trauma, there may
be multiple severe intraparenchymal hematomas
...
Involvement of
the alveolar nerve in the callus
may cause neuralgic pain
...




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