Cross Sectional Anatomy of the Neck

This set covers the cross-sectional anatomy, fascial layers, compartments, and major vascular structures of the human neck based on RDGY220 lecture materials.

Superior boundary of the neck

The inferior margins of the mandible/skull and the superior nuchal line.

Inferior boundary of the neck

The acromia, clavicle, sternum, and the spinous process of $C7$ ($CVII$).

Anatomical levels of the neck

Defined by the cervical vertebrae ($C1-7$), the hyoid bone, and laryngeal cartilages.

Deep cervical fascia layers

Consists of the investing layer, pretracheal layer, prevertebral layer, and the carotid sheath.

Musculofascial collar

The outermost layer that encloses all the other fascial compartments of the neck.

Vertebral compartment

Contains the cervical vertebrae and their associated muscles.

Visceral compartment

Contains the larynx, trachea, pharynx, oesophagus, and the thyroid gland.

Vascular compartment

An individual compartment on each side of the neck surrounded by the carotid sheath, containing major vessels and nerves.

Carotid sheath contents

Contains the common/internal carotids, internal jugular vein, vagus nerve ($CNX$), and deep cervical lymph nodes.

Right common carotid artery

A branch of the brachiocephalic trunk that ascends in the neck lateral to the trachea.

Left common carotid artery

A direct branch of the aortic arch.

External carotid artery

A terminal branch of the common carotid that supplies the external head and neck.

Internal carotid artery

A terminal branch of the common carotid that supplies intracranial structures and the eye.

Carotid sinus

A dilation at the start of the internal carotid artery that contains baroreceptors to monitor blood pressure.

Carotid body

A structure located at the carotid bifurcation that monitors blood composition.

Hyoid bone anatomical level

Corresponds to the level of the body of the $C3$ vertebra.

Thyroid cartilage level

Located at the level of the $C4$-$C5$ vertebrae.

Cricoid cartilage level

Located at the level of $C6$, marking the pharyngo-oesophageal junction (poj) and laryngo-tracheal junction (ltj).

Thyroid gland isthmus

The central portion of the thyroid gland located at the level of tracheal rings $2$-$4$.

Platysma

A superficial muscle of the neck seen in cross-sections at the level of $C5$ and $T1$.