The region of the body between head and chest (thorax); anatomists use the adjective cervical for this zone.
Structurally there are seven cervical vertebrae with closely associated muscle groups. The great vessels, carotid arteries and jugular veins lie deep to the sterno-cleido-mastoid muscle and typically pulsations are sought there. This very visible muscle extends obliquely from the inner aspect of the collar bone to insert behind the ear at the mastoid process of the skull.
In the space between the two sternomastoid (cleido is commonly omitted) muscles is the centrally placed trachea (windpipe) and the prominent larynx (voice box); the most prominent feature is the notched thyroid cartilage. Below that is the cricoid cartilage and above it, beneath the jaw, the invisible but easily felt “wishbone-shaped” hyoid bone – the medical examiner expects to find this broken in cases of manual strangulation.
The esophagus (gullet) lies behind the trachea and cannot readily be discerned there; it is, however, mobile and both trachea and esophagus can be pushed aside in the lower neck so one can feel the anterior aspect of the lower cervical vertebrae – in fact an approach commonly used in operations on the cervical discs. The tips of the transverse processes of the first cervical vertebra (atlas) can be felt between the angle of the mandible and the mastoid process.
Lymph nodes lie alongside the great vessels deep to sternomastoid, the grouping known as “anterior triangle” since for convenience in description the sternomastoid divides the neck into anterior and posterior triangles. Usually these cannot be palpated, sometimes an upper node, called tonsillar can be felt.
The sloping appearance of the posterior neck is given by the trapezius muscle, the two together produce a cowl-like appearance when the head and shoulders are viewed from behind.
In the posterior triangle, between sterno-mastoid and trapezius, can be felt the bundle of emerging nerve structures which form the brachial plexus.