Supraclavicular

The supraclavicular nerves emerge beneath the posterior border of the sternocleidomastoideus (sternocleidomastoid muscle), and descend in the posterior triangle of the neck beneath the platysma muscle and the deep cervical fascia. Together, they innervate skin over the shoulder. The supraclavicular nerve can be blocked during shoulder surgery.

The cervical plexus is formed by the ventral rami of the upper four cervical nerves and the upper part of fifth cervical ventral ramus. the network of rami is located deep to the sternocleidomastoid within the neck. the cervical plexus innervates muscles of the neck and areas of skin on the head, neck and chest. the deep branches innervate muscles, while the superficial branches supply areas of skin. a long branch (primarily of fibers of c4 and with contributions of fibers from c3 and c5; nervus phrenicus) innervates muscles of the diaphragm. the cervical plexus also communicates with the cranial nerves vagus nerve and hypoglossal nerve.