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TOPOGRAPHIC ANATOMY OF THE NECK
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The neck lies between the lower margin of the mandible and the superior nuchal
line of the occipital bone above and the suprasternal notch and the upper border of the
clavicle below.
The neck is divided into two divisions by frontal plane which passes through
transverse processes of the cervical vertebrae: anterior and posterior.
Posteriorly muscles lie on either side of cervical spinous processes and a more
superficial layer formed by the trapezius muscles.
Anteriorly and in the midline we find the respiratory and alimentary passages
flanked by vascular and nervous structures. Centrally the neck is supported by the
cervical vertebral column from which the spinal nerves emerge laterally.
Fig. 1. Regions of the neck.
1 – submental triangle,
2 – carotid triangle,
3 – omotracheal triangle,
4 – omotrapezoid triangle,
5 – omoclavicular triangle,
6 – submandibular triangle,
7 – sternocleidomastoid
region,
8 – digastric muscle
9 – omohyoid muscle
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The anterior division of the neck in its turn is divided into three regions: medial
triangle, lateral triangle and sterÂnocleidomastoid region (Fig. 1).
The boundaries of the medial triangle of the neck are:
anteriorly – the median line of the neck;
posteriÂorly – the anterior border of the sternocleidomastoid;
superiorÂly – the inferior of the mandible.
The medial triangle is furtÂher subdivided into smaller triangles: carotid,
submandibular, submental and scapulotracheal (omotracheal).
The line, which is drown through the body of hyoid bone divides both medial
triangle into infrahyoid region and suprahyoid region.
The submental and two submandibular triangles are located in the suprahyoid
region.
The two omotracheal triangle are located it infrahyoid region.
Fig. 2.
Landmarks of the neck
FASCIAS OF THE NECK
We use classification of the fasciae of the neck on Shevkunenko.
They are five fasciae (Fig. 3):
1. Superficial fascia of the neck forms a thin layer, which lies between the skin and
the proper fascia. Anteriorly is contains the platysma muscle.
2. The second fascia is a superficial layer of the proper fascia. It surrounds the
neck and also it split to enclose the sternocleidomastoid muscle, trapezius muscle and
submandibular glands.
Superiorly the fascia is attached to the lower border of the mandible. Inferiorly the
fascial layer is attached to the acromion, to anterior margins of the clavicle and the
manubrium sterni.
3. The third fascia is a deep layer of proper fascia.
Inferiorly the fascia is attached to the posterior margins of the upper border of the
manubrium and the clavicle.
Fig. 3. Fascias and fat spaces of the neck on horizontal section
1 – I fascia, 2 – trachea, 3 – esophagus, 4 – sternothyroid and 5 – sternohyoid
muscles surrounded by III fascia, 6 – thyroid gland, 7 – platysma, 8 – common carotid
artery, 9 – sternocleidomastoid muscle surrounded by II fascia, 10 – internal jugular vein,
11 – omohyoid muscle, 12 – scalenus anterior muscle, 13 – scalenus medius muscle, 14
– scalenus posterior muscle, 15 – levator scapulae muscle, 16 – profunda cervical
artery and vein, 17 – trapezius muscle, 18 – CVII, 19 – nuchal ligament, 20 – vertebral
artery and vein, 21 – brachial plexus, 22 – external jugular vein, 23 – vagus nerve, 24
– longus colli muscle.
Between the second fascia and the third fascia there is a slitlike space called the
suprasternal space which contains the jugular venous arch.
This fascia, trapezium-shaped, on each side is bounded by omohyoid muscle. It
surrounds the infrahyoid muscles. They are the sternohyoid, the omohyoid, the
thyrohyoid, the sternothyroid muscles.
4. The fourth fascia is endocervical fascia. It consists of two layers: visceral and
parietal.
The visceral layer surrounds all the organs of the neck.
The parietal layer forms sheath for main vessels and nerves of the medial triangle.
They are common and internal carotid arteries, the internal jugular vein, vagus nerve and
the ansa cervicalis. And also the parietal layer is adjacent to posterior surface of the
sheath of the infrahyoid muscle.
5. The fifth fascia is prevertebral fascia. It covers the prevertebral muscles, namely
the longus capitis and longus cervicis, forms the floor of the lateral triangle and sheath for
the main vessels and nerves of the lateral triangle. They are subclavian artery and vein
and brachial plexus. And also this fascia surrounds the sympathetic trunk.
FAT SPACES OF THE NECK
They are ten.
The second fascia of the neck or superficial layer of proper fascia forms the
following fat spaces of the neck:
1. Sheath for submandibular gland, which contains vessels, nerves,
submandibular gland, lymphatic modes and fat.
2. Sheath for sternocleidomastoid muscle. Fat is located between posterior surface
of the muscle and its sheath.
3. Between the second fascia and the third fascia is located suprasternal space,
which contains the jugular venous arch.
4. This space is communicated with blind retrosternocleidomastoid sac (Gruber),
which is located between: anteriorly – posterior surface of the sheath
sternocleidomastoid muscle and posteriorly – the third fascia or deep layer of proper
fascia. Blind retrosternocleidomastoid sac is communicated with fat of the sheath
sternocleidomastoid muscle.
5. Between the visceral and parietal layers of the fourth fascia or endocervical
fascia is located previsceral space, which spreads from the hyoid bone to the suprasternal
notch and further it is communicated with fat of the anterior mediastinum. Fat is located
before organs of the neck and is more expressed before trachea.
It is the so-called pretracheal fat space. It contains lymph
nodes, inferior thyroid veins and thyroidea ima artery in 12% of the cases.
6. Narrow split along the main vessels and nerves of the medial triangle is
neurovascular space of the medial triangle. Sheath for main vessels and nerves of the
medial triangle bounds its. This space upward reaches to the base of the skull and downÂward it passes into the fat of anterior mediastinum. This space contains fat, lymphatic
nodes.
7. Between the visceral layer of the endocervical fascia anteriorly and the
prevertebral fascia posteriorly is located retrovisceral spaceÂ
(retropharyngeal,
retroesophageal). It is communicated with the fat of the posterior mediastinum and
reaches to the base of the skull – superiorly and to the diaphragm – inferiorly.
8. The superficial fat space of the lateral triangle is located between the second
fascia and fifth fascia. This is communicated with the fat spaces of the scapular region
(fat of supraspinous fossa and fat between the trapezius muscle and supraspinatus
muscle).
9. The fifth fascia forms deep fat space or neurovascular space of the lateral
triangle. It is located in sheath for vessels and plexus and is communicated with the fat
sheath for vessels and nerves of the axillary fossa.
10. The prevertebral fat space is located between the prevertebral fascia anteriorly
and the prevertebral muscles (longus cervicis muscle and longus capitis muscle) that is
behind the prevertebral fascia.
Pus arising from the tuberculosis of the upper cervical vertebrae is limited in front
by the prevertebral fascia. A midline swelling is formed, which bulges forward in the
posterior wall of the pharynx. The pus then tracks laterally and downward behind the
carotid sheath, to reach the lateral triangle. Here, the fascia, which forms a covering to
the muscular floor of the triangle, is weaker, and the abscess points behind the
sternocleidomastoid. Rarely, the abscess may track downward behind the prevertebral
fascia, to reach the superior and posterior mediastinum in the thorax.
THE SUPRAHYOID REGION
The boundaries this region are:
superiorly – inferior margin of the mandible,
inferiorly – line, which is drown through body of hyoid bone on each side,
laterally – the anterior border sternocleidomastoid muscle.
The suprahyoid region is covered by skin, superficial fascia, platysma, superficial
layer of proper fascia. Running across the region in this covering are the cervical branch
of the facial nerve and the transverse cutaneous nerve. This region contains the
submental and two submandibular triangles.
THE SUBMENTAL TRIANGLE
The submental triangle lies below the chin and bounded laterally by the right and
left anterior bellies of the digastric muscles and inferiorly by the body of the hyoid bone.
The floor of the triangle is formed by the mylohyoid muscle. It contains the submental
lymph nodes and the beginning of the anterior jugular vein.
THE SUBMANDIBULAR TRIANGLE
The submandibular triangle bounded by (Fig. 4, 7):
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Fig. 4. Submandibular and carotid triangles
1 – digastric muscle (posterior belly), 2 – internal carotid artery, 3 – external carotid
artery, 4 – stylohyoid muscle, 5 – retromandibular vein, 6 – facial artery and vein, 7
– submandibular lymph nodes, 8 – submental vein, 9 – submandibular gland, 10 –
mylohyoid muscle, 11 – digastric muscle (anterior belly), 12 – lingual artery, 13 –
anterior jugular vein, 14 – hyoid bone and hyoglossus muscle, 15 – sternohyoid muscle,
16 – omohyoid muscle (superior belly), 17 – thyrohyoid muscle, 18 – thyrohyoid
membrane, 19 – thyroid gland, 20 – sternocleidomastoid muscle, 21 – common carotid
artery, 22 – ansa cervicalis, 23 – superior thyroid artery and vein, 24 – superior
laryngeal nerve, 25 – facial vein, 26 – deep cervical lymph nodes, 27 – superior radix
ansa cervicalis, 28 – vagus nerve, 29 – hypoglossal nerve, 30 – internal jugular vein, 31
– external jugular vein and accessory nerve, 32 – parotid gland
1. Inferior border of mandible.Â
2. Anterior belly of digastric.
3. Posterior belly of digastric.
The floor of the triangle is formed by mylohyoid and hyoglossus muscles.
The triangle contains the submandibular salivary gland with the facial artery deep
to it and the facial vein and submandibular lymph nodes superficial to it and fat.
The hypoglossal nerve runs on the hyoglossus muscle deep to the gland.
The submandibular duct emerges from beneath the anterior border of the gland
and runs forward on the surface of hyoglossus under mylohyoid muscles.
The lingual artery arises from the anterior surface of the external carotid artery
above the superior thyroid artery. It loops upward and then passes deep to the posterior
border of the hyoglossus muscle to enter the submandibular region.
The lingual artery may be found for ligation in Pirogoff’s triangle, which
bounded (Fig. 7):
superiorly – by hypoglossal nerve,
inferiorly – by intermediate tendon of digastric muscle,
anteriorly – by mylohyoid muscle.
For exposure of artery it is necessary to separate the floor of the triangle – the
hyoglossus muscle.
The sheath of submandibular gland is formed by the second fascia of the neck,
which divides into two layers. These layers are attached to the inferior border of the
mandible. The submandibular gland is separated from the parotid gland by thick fascial
septum.
THE INFRAHYOID REGION
The boundaries this region are:
superiorly – line, which is drown through body of hyoid bone,
inferiorly – the suprasternal notch,
laterally – anterior borders the sternocleidomastoid muscles.
The infrahyoid region is covered by skin, subcutaneous tissue, superficial fascia,
platysma, the superficial layer of the proper fascia, the deep layer of the proper fascia,
the infrahyoid muscles, the parietal and visceral layers of the endocervical fascia.
Running across the region in this covering are the branches of the transverse cutaneous
nerve.
The region contains the carotid triangle and two omotracheal triangles (muscular
triangle).
The omotracheal triangle is bounÂded:
anteriorly – by the midline of the neck,
superiorly – by the superior belly of the omohyoid and
inferiorly – by the anterior border of the sternocleidomastoid muscle.
Its floor is formed by the sternohyoid and sternothyroid muscles. Beneath the floor
and the parietal and visceral layers of the endocervical fascia lie the organs of the neck.
They are the thyroid gland, the larynx, the trachea, the pharynx and the esophagus.
THE LARYNX
The larynx lies below the oropharynx and the pharyngeal portion of the tongue. It
opens into the laryngopharynx above and is continuous with the trachea below. It is
primarily a sphincter which is able to separate the respiratory from the alimentary tract
and its adaptation for phonation is a secondary feature. It consists of a skeleton of
cartilages and membranes built around the first part of the respiratory tract. The shape
and position of the skeletal elements are maintained or altered by a group of intrinsic
muscles (Fig. 5).
The cricoid cartilage forms the foundation for the laryngeal skeleton. The thyroid
cartilage consists of two laminae which are united anteriorly at the laryngeal
prominence or "Adam's apple".
The epiglottis, a gently curved leaf-like structure, is attached inferiorly to the
internal aspect of the upper border of the thyroid cartilage. Its free upper portion projects
superiorly above the level of the hyoid bone.
The upper border of the thyroid cartilage is joined to the deep surface of the body
of the hyoid bone by the thyrohyoid membrane.
The cricoid, thyroid and arytenoid cartilages are joined by the cricothyroid
membrane.
The larynx is located from the superior border V cervical vertebra to the inferior
border VI cervical vertebra, but the epiglottis reaches to III cervical vertebra.
The sternohyoid muscle, the sternothyroid muscle and the pyramidal lobe of the
thyroid gland if present are located ...
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