Triangles of the neck
The neck is the region of the body that lies between the lower margin of the mandible above and the suprasternal notch and the upper border of the clavicle below. It is strengthened by the cervical part of the vertebral column. In the central region of the neck are parts of the respiratory system, namely, the larynx and the trachea, and behind are parts of the alimentary system, the pharynx and the esophagus. At the sides of these structures are the vertically running carotid arteries, internal jugular veins, the vagus nerve, and the deep cervical lymph nodes.
Skin of the Neck
The natural lines of cleavage of the skin are constant and run almost horizontally around the neck. This is important clinically because an incision along a cleavage line will heal as a narrow scar, whereas one that crosses the lines will heal as a wide or heaped-up scar.
The skin overlying the trapezius muscle on the back of the neck and on the back of the scalp as high as the vertex is supplied segmentally by posterior rami of cervical nerves 2 to 5.
The skin of the front and sides of the neck is supplied by anterior rami of cervical nerves 2 to 4 through branches of the cervical plexus. The branches are:
Lesser occipital nerve (C2) supply the skin over the lateral part of the occipital region and the medial surface of the auricle.
Great auricular nerve (C2 and 3) supply the skin over the angle of the mandible, the parotid gland, and on both surfaces of the auricle.
Transverse cutaneous nerve (C2 and 3) supply the skin on the anterior and lateral surfaces of the neck, from the body of the mandible to the sternum.
Supraclavicular nerves (C3 and 4) supply the chest wall and shoulder region, down to the level of the second rib
Medial supraclavicular nerve supplies the skin as far as the median plane.
Intermediate supraclavicular nerve supplies the skin of the chest wall.
Lateral supraclavicular nerve crosses the lateral end of the clavicle and supplies the skin over the shoulder and the upper half of the deltoid muscle; this nerve also supplies the posterior aspect of the shoulder as far down as the spine of the scapula.
Cervical nerves and cutaneous branches