Ansa_cervicalis
Ansa cervicalis
From cervical plexus
The ansa cervicalis (or ansa hypoglossi in older literature[citation needed]) is a loop formed by muscular branches of the cervical plexus formed by branches of cervical spinal nerves C1-C3. The ansa cervicalis has two roots - a superior root (formed by branch of C1) and an inferior root (formed by union of branches of C2 and C3) - that unite distally, forming a loop. It is situated within the carotid sheath.[1]: 334
Branches of the ansa cervicalis innervate three of the four infrahyoid muscles: the sternothyroid, sternohyoid, and omohyoid muscles (note that the thyrohyoid muscle is the one infrahyoid muscle not innervated by the ansa cervicalis - it is instead innervated by cervical spinal nerve 1 via a separate thyrohyoid branch[2]: 582, 600 ).
Its name means "handle of the neck" in Latin.[citation needed]