Overview of the neck

Question 1

What are the contents of the superficial cervical fascia?

Answer 1

Cutaneous nerves, blood and lymphatic vessels, lymph nodes, fat, and the platysma muscle.

Question 2

What is the innervation and function of the platysma muscle?

Answer 2

The platysma is innervated by CN VII (facial nerve). It serves to tense the neck (like when shaving).

Question 3

What are the five layers of deep cervical fascia?

Answer 3

The investing layer, the muscular/infrahyoid layer, the pretracheal layer of the visceral layer, the buccopharyngeal layer of the visceral layer, and the prevertebral layer.

Question 4

What is the most superficial layer of the deep cervical fascia?

Answer 4

The investing layer.

Question 5

What structures does the investing layer enclose?

Answer 5

The investing layer encloses the trapezius muscle, the sternocleidomastoid muscle, the parotid gland, and the submandibular gland (two muscles and two glands).

Question 6

What does the investing layer wrap around?

Answer 6

Despite “investing” only two muscles and two glands, the investing fascia wraps around the entirety of the neck, just deep to the superficial fat and fascia.

Question 7

What separates the parotid and submandibular glands within the investing fascia?

Answer 7

The stylomandibular ligament.

Question 8

What are the superior attachments of the investing layer?

Answer 8

Superiorly to the top of the jaw (zygomatic arches), posteriorly at the superior nuchal line of the occipital bone, anteriorly to the mastoid processes, and inferiorly at the inferior border of the mandible.

Question 9

What are the inferior attachments of the investing layer?

Answer 9

The manubrium, clavicles, acromion, and spines of the scapulae. It also attaches to the hyoid bone and spinous processes of the cervical vertebrae on its way down the neck.

Question 10

What is the suprasternal space?

Answer 10

A separation in the investing layer at the anterior and posterior aspects of the manubrium (to accommodate the sternal head of the SCM).

Question 11

What is contained in the suprasternal space?

Answer 11

The inferior ends of the anterior jugular veins and the jugular venous arch (as well as some lymph nodes).

Question 12

What does the the muscular layer of the deep cervical fascia contain?

Answer 12

The muscular layer contains the infrahyoid muscles.

Question 13

What else is found in the muscular layer?

Answer 13

The muscular layer also contains the thickened loops/tethers for the two bellies of the digastric and the omohyoid respectively.

Question 14

What are the loops in the muscular layer called?

Answer 14

Intermediate tendons. One separates the anterior and posterior bellies of the digastric, and the other separates the superior and inferior bellies of the omohyoid.

Question 15

Where is the digastric intermediate tendon located?

Answer 15

At the hyoid bone (where the anterior and posterior bellies of the digastric meet up).

Question 16

Where is the omohyoid intermediate tendon located?

Answer 16

At the clavicle (remember the omohyoid extends from the hyoid to the scapula).

Question 17

What does the muscular layer extend to and from?

Answer 17

From the hyoid to the sternum/clavicle.

Question 18

Where is the visceral layer of the deep fascia found?

Answer 18

In the anterior portion of the neck, since this is where the viscera of the neck is.

Question 19

What two layers does the visceral layer of the deep cervical fascia divide into?

Answer 19

The pretracheal layer (anterior) and the buccopharyngeal layer (posterior).

Question 20

What does the pretracheal layer contain?

Answer 20

The trachea, the thyroid gland, and the esophagus.

Question 21

What does the buccopharyngeal layer contain?

Answer 21

The pharynx and pharyngeal constrictors.

Question 22

What does the pretracheal layer form a fibrous connection between?

Answer 22

The pretracheal layer forms a fibrous connection between the hyoid and the fibrous pericardium of the heart.

Question 23

What does the prevertebral layer of the deep cervical fascia contain?

Answer 23

The vertebral column, the longus colli, the longus capitus, the scalene muscles, the deep cervical muscles, and the cervical portion of the sympathetic chain.

Question 24

What does the prevertebral layer extend to and from?

Answer 24

From the base of the skull to the coccyx, fused to the anterior longitudinal ligament and enveloping the vertebral bodies and associated ligaments.

Question 25

What does the prevertebral layer attach to laterally?

Answer 25

The transverse processes of the vertebrae.

Question 26

What does the prevertebral layer attach to cervically?

Answer 26

It will cover the scalene muscles and form the floor of the posterior triangle.

Question 27

What two layers does the prevertebral layer split into in the cervical region?

Answer 27

After contributing to the carotid sheath, the prevertebral layer divides into a prevertebral layer and an alar layer.

Question 28

After splitting, where will the prevertebral layer continue into?

Answer 28

Part of the prevertebral fascia will ultimately continue into the upper extremities as the axillary sheath (the brachial plexus and axillary vessels traverse this).

Question 29

What does the alar layer separate?

Answer 29

The alar layer separates the retropharyngeal space from danger space 4.

Question 30

What else does the alar layer cover?

Answer 30

The alar layer covers the cervical portion of the sympathetic chain.

Question 31

What fascial layers comprise the carotid sheath?

Answer 31

The carotid sheath is composed of a blending of all three layers of deep cervical fascia (the investing layer, the visceral layer, and the prevertebral layer).

Question 32

What does the carotid sheath contain?

Answer 32

The common and internal carotid arteries, the internal jugular veins, the vagus nerve, deep cervical lymph nodes, the carotid sinus nerve, and some sympathetic fibers.

Question 33

What is clinically relevant about the carotid sheath aside from the structures it contains?

Answer 33

It represents an open pathway from the mediastinum into the skull (can be a route for infection or bleeding).

Question 34

What is the retropharyngeal space?

Answer 34

A large space formed between the alar fascia and the fascia of the pharyngeal constrictors (buccopharyngeal fascia) that extends from the base of the skull to around T1/T2.

Question 35

What is the significance of the retropharyngeal space?

Answer 35

It allows for the necessary movement of the pharynx, esophagus, larynx, and trachea during swallowing.

Question 36

What else is clinically relevant about the retropharyngeal space?

Answer 36

It is a common site of deep neck infections, and can allow ear/nose/throat infections to spread down into the alar fascia.

Question 37

What can an infection in the retropharyngeal space potentially cause?

Answer 37

It can degrade the alar fascia and spread into danger space 4.

Question 38

What is danger space 4?

Answer 38

A space formed between the prevertebral fascia and the alar fascia that extends from the base of the skull to the diaphragm, and is continuous with the posterior mediastinum.

Question 39

What transverses danger space 4?

Answer 39

The sympathetic chain.

Question 40

What is the basis for the name “danger space 4”

Answer 40

There is very little resistance to the spread of infection though this area. It represents a rout of infection from the mouth to the mediastinum/thorax.

Question 41

What fascia layer is the roof of the anterior triangle of the neck?

Answer 41

The superficial cervical fascia.

Question 42

What is the floor of the of the anterior triangle of the neck?

Answer 42

The pharynx, larynx, and thyroid gland.

Question 43

What do the lymph nodes nodes in the submental triangle drain?

Answer 43

They mostly drain the tongue and floor of the mouth.