Ansa cervicalis nerve

The ansa cervicalis is a nerve loop formed by the union of fibers from cervical spinal nerves C1-C3. It consists of a superior root (derived from C1-C2 fibers that travel with the hypoglossal nerve) and an inferior root (formed from C2-C3 fibers). Located anterior to the carotid sheath deep to the sternocleidomastoid muscle, the ansa cervicalis provides motor innervation to three of the four infrahyoid muscles: the omohyoid, sternohyoid, and sternothyroid. While not a conventional drug target, the ansa cervicalis has gained clinical relevance in recent years as a donor nerve for reinnervation procedures aimed at restoring vocal cord function in cases of laryngeal paralysis. The nerve demonstrates significant anatomical variation, particularly in the course of its inferior root, which is asymmetric in approximately 75% of cases.

Other names

Ansa hypoglossiCervical loopNeural loop of the neck