Anterior Ramus of Third Cervical Nerve

Origin

The anterior ramus of the third cervical nerve originates from the third cervical nerve.

Course

The anterior ramus of the third cervical nerve originates in the neck, lateral to the intervertebral foramen between the second and third cervical vertebrae. It runs laterally and contributes to the formation of cervical plexus along with anterior rami of the first to fourth cervical nerves.

Branches

There are no named branches of the anterior ramus of the third cervical nerve; however, it does contribute to the cervical plexus.

Supplied Structures

The anterior ramus of the third cervical nerve conveys motor fibers to the cervical plexus, thus innervating the infrahyoid muscles (sternohyoid, sternothyroid and inferior belly of omohyoid) via the ansa cervicalis. Other muscles innervated include the anterior prevertebral muscles, including the longus capitis and longus colli, and lateral prevertebral muscles, including the middle scalene muscle.

Sensory afferent neurons from the great auricular, supraclavicular, and transverse cervical nerves also transmit general sensory information from the skin of the anterolateral neck via the anterior ramus.

The sympathetic innervation to blood vessels and glands in the head and neck region originates in the lateral horn of the first thoracic spinal segment and ascends in the sympathetic chain to reach the superior cervical ganglion. From here, the postganglionic sympathetic neurons enter the anterior ramus of the third cervical nerve via the gray communicating branches (gray rami communicantes containing postganglionic sympathetic fibers) and get subsequently distributed to vessels and glands.