Neck

Question 1

What muscle is the landmark for dividing regions of the neck?
What regions is the neck divided?

Answer 1

Sternomastoid (attaches from mastoid process to clavicle) & important for rotation & lateral flexion of neck

Posterior to the sternomastoid is posterior triangle & vertebral region

Sternomastoid region forms the root of the neck

In front of the muscle is the anterior triangle

Question 2

Describe the layers & components of the superficial fascia

Answer 2

Superficial fascia external layer containing the skin, sub-cutaneous tissue, fat & cutaneous/superficial neurovascular supply

Also contains plasma muscle which blends with the muscles of facial expression
Superficial veins = external jugular and anterior jugular
EJV begins at the angle of the mandible and descents on sternomastoid
AJV descend in the midline (x2)

Question 3

Describe the layers & components of the deep fascia

Answer 3

4 layers

Investing layer - outer layer that invests the neck, splitting to surround trapezius (posteriorly) and sternomastoid (anteriorly)

Prevertebral layer - invests muscles surrounding vertebral column - extensors of the neck that support the cervical lordosis and head

Pretracheal layer - invests the thyroid and sits anterior to the trachea

Carotid sheet - 2 laterally which invest the common carotid artery, vagus nerve and internal jugular vein
Thin and expansile to accomodate vein. Veins lateral to arteries

Question 4

What are the features of the cervical spine?

Answer 4

C1-C7

Form a lordosis to support the head upright - reinforced by strong muscles

Question 5

What are the clinical implications of the fascia?

Answer 5

Allows tracking of infective material and blood along length of the fascia to other structures

Spaces between the facial cylinders communicate with the mediastinum also, can spread infection to the thorax

Question 6

What are the typical cervical vertebrae and what are there features?

Answer 6

C3 - C6
Hollowed out vertebral bodies - uncinate processes
Lateral masses with anterior & posterior tubercles, joined by a thin bar of bone that creates a transverse foramin
Transverse foramen allows passage of vertebral artery
Bifurcate spinous proces to allow attachment of many muscles

Question 7

What are the atypical cervical vertebrae and their features?

Answer 7

C1, C2 (atlas & axis) and C7

C7 has a long spinous process

Atlas (C1) - no body, longest transverse process, facet for dens and anterior & posterior arches
ALLOWS FREE MOVEMENT OF HEAD ON C2

Axis (C2) - Dens (developmental body of C1), facets for articulation with arch of atlas
Strong spinous process

Question 8

What are the posterior/lateral muscles of the neck?

Which in particular is an important landmark in the neck and for what structures?

Answer 8

Scalenous muscles
Anterior - medius - posterior
Attach from anterior & posterior tubercles of cervical spine & insert onto ribs
Located in the PREVERTEBRAL FASCIA

Scalenus anterior important landmark
Phrenic nerve sits and descends on it
Between scalenous anterior and medius the SUBCLAVIAN ARTERY & BRACHIAL PLEXUS are located

Question 9

What are important cervical vertebrae landmarks for the carotid artery & vertebral artery?

Answer 9

Anterior tubercle (carotid tubercle) @ C6 - common carotid can compress against this

Bifurcation of common carotid @ C4

Vertebral artery in transverse foramina associated with C1 - C6

Question 10

Which divisions of the common carotid branch within the region of the neck?

What are the branches?

Answer 10

The internal carotid artery is more posteriorly located and DOESN”T branch within the neck

External carotid artery more anterior and DOES branch within the neck
Anterior branches = facial, lingual and superior thyroid artery
Posterior = posterior auricular, occipital arteries

Question 11

Features of the cervical IV discs

Answer 11

Largest discs relative to the size of body
Sit within the uncinate process of the body & are protected
Prevent forward slip and rotation

Question 12

What are the 3 compartments of the neck?

Answer 12

Vertebral - posterior compartment - contains back/posture musculature & vertebrae

Visceral compartment - anterior to vertebral column and is related to the trachea & oesophagus. Contains the thymus, parathyroid glands

Vascular compartment - 2 laterally which comprise the carotid sheath

Question 13

What is a clinically relevant feature of the pretrachial fascia?

Answer 13

Connects to the hyoid bone, therefore moves up and down with swallowing
Invests the thyroid gland so if lump which moves with swallowing know it is on the thyroid gland

Question 14

What are the anterior muscles of the neck?

Answer 14

Anterior muscles = suprahyoid & infrahyoid (strap) muscles

Suprahyoid attach to the skull & hyoid bone to elevate the hyoid bone and larynx

Infrahyoid attach to the hyoid bone and to sternum, clavicle or scapula to depress the hyoid and larynx

Question 15

Which cranial nerves are associated with the neck?

Answer 15

CN 9, 10, 11

CN 9 projects antero-inferior to oral cavity

CN 10 descends in the carotid sheath (lateral)

CN 11 descends posteriorly, going through sternomastoid

Question 16

What is the position of the thyroid gland in relation to the trachea & other landmarks?

What nerve is associated with the thyroid?

Answer 16

Thyroid gland extends between the upper border of the gyroid cartilage to the 6th tracheal ring

The isthmus crosses between 2nd & 3rd tracheal cartilage ring

It is anterior to the trachea & oesophagus and posterior to the strap muscles (infra hyoid muscles)
The lobes are adjacent to and overlap the carotid sheaths

The recurrent laryngeal is adherent to the fascia of the posterior aspect of the thyroid

Question 17

What is the vascular supply of the thyroid?

What is a possible variation?

Answer 17

Superior thyroid artery (anterior branch of ECA) x2
Inferior thyroid artery (branch of subclavian artery) x2

3 pairs of veins (superior, middle and inferior thyroid)

Variation - 10% have an Ima artery which if present ascends anteriorly on the trachea and passes along the isthmus

Question 18

What are the consequences of an enlarged thyroid?

Answer 18

Compression of structures
Oesphagus - dysphagia
trachea - respiratory obstruction 
recurrent layngeal nerve - hoarse voice
internal jugular veins - venous distension

Question 19

How does the thyroid develop?

Answer 19

Develops from the floor of the oropharynx and descends

Foramen cecum on tongue (anterior to sulcus terminalis) is remnant of its development

Question 20

What spinal routes form the cervical plexus & what are important terminal branches?

Answer 20

Ventral rami of C1-4

Phrenic nerve (C3,4,5) - descends in the posterior triangle of the neck on scalenous anterior

Superficial cutaneous - skin

Deep branches - ansa cervicalis - motor to strap muscles of neck