The Neck - General Overview

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Last updated 1 April 2006

Surface Anatomy of the Neck

On the posterior aspect, the spinous process of C2 is the first bony prominence that can be felt below the external occipital protuberance.
The spinous process of the vertebra prominens (C7) is easily palpable and usually clearly visible when the neck is flexed.

The laryngeal prominence is the important surface feature of the anterior part of the neck when. It is produced by the thyroid cartilage, the largest part of the laryngeal skeleton.

Bony-cartilaginous framework (p. 783)

The Thyroid Cartilage (p. 783)

This is located at the level of C4-C5 and is part of the laryngeal skeleton.
It consists of two quadrilateral plates called laminae, which can easily be felt.

The Hyoid Bone (p. 783)

This lies superior to the thyroid cartilage.
It is a U-shaped bone level with the body of C3.
It is the first resistant structure that can be felt in the median plane inferior to the chin.
When the neck is relaxed the tips of the greater horns (L. cornua) can be palpated.

The Cricoid Cartilage (p. 783)

This is part of the laryngeal skeleton. It lies inferior to the thyroid cartilage.
The cricoid cartilage lies at the level of C6 vertebra, where the pharynx joins the oesophagus and the larynx and trachea join each other.

The Tracheal Rings (p. 783)

Superficial Neck Muscles

Fascial Planes of the Neck

The deep cervical fascia is disposed in three layers: investing, pretracheal and prevertebral.

The Investing Fascia (p. 823)

This is the superficial or investing layer of the deep cervical fascia.
It encircles or forms a collar around the neck, surrounding the structures in it.
It is located between the superficial fascia and the muscular layer.

The investing fascia is attached superiorly to the superior nuchal line of the occipital bone, the mastoid process, the zygomatic arch, the inferior border of the mandible, the hyoid bone, and the spinous processes of the cervical vertebrae.
Inferiorly, the investing fascia is attached to the manubrium of the sternum, the clavicle, and the acromion and spine of the scapula.

Just superior to the sternum, the investing fascia divides into two layers. These are attached to the anterior and posterior surfaces of the manubrium.
The interval between these layers is called the suprasternal space.
It encloses the sternal heads of the sternocleidomastoid muscles, the inferior ends of the anterior jugular veins and the jugular venous arch.

The investing fascia also forms the roof of the anterior and posterior triangles of the neck.

The Pretracheal Fascia (p. 823)

This is a thin layer of deep cervical fascia that is anterior to the trachea and limited to the anterior aspect of the neck.
It extends inferiorly from the thyroid cartilage and the arch of the cricoid cartilage into the thorax.

The pretracheal fascia lies deep to the infrahyoid muscles.
It splits to enclose the thyroid gland, trachea, and oesophagus and blends laterally with the carotid sheath. Thus, it encloses the viscera of the neck.

The Prevertebral Fascia (p. 825)

This layer of deep cervical fascia forms part of a tubular sheath for the prevertebral muscles that surrounds the vertebral column.
It is also continuous with the deep fascia covering the muscular floor of the posterior triangle of the neck.

The prevertebral fascia extends from the base of the skull to the third thoracic vertebra, where it fuses with the anterior longitudinal ligament.

The prevertebral fascia extends inferiorly and laterally as the auxiliary sheath, which surrounds the axillary vessels and brachial plexus.

The Carotid Sheath (pp. 801-2)

This is a tubular, thickly matted fascial condensation that extends from the base of the skull to the root of the neck.
It is formed by fascial extensions of the cervical fascia, which fuse with the pretracheal fascia.

The inferior part of the carotid sheath contains several clinically important structures: (1) the common carotid arteries medially; (2) the internal jugular vein laterally; (3) the vagus nerve (CN X) posteriorly; and (4) the ansa cervicalis.

The superior root of the ansa cervicalis descends between the common carotid and the internal jugular vein and is sometimes embedded in the carotid sheath.
Many deep cervical lymph nodes lie along the carotid sheath and the internal jugular vein and between this vein and the common carotid arteries.
The cervical part of the sympathetic trunk runs posterior to the carotid sheath.

Triangles of the Neck

The neck can be divided into two triangles, the anterior and posterior triangles, separated by the sternocleidomastoid muscle.

Root of the Neck