Nerve · Neck

Ansa cervicalis

Ansa cervicalis

A thin loop of nerve lying on the front of the carotid sheath, midway between the jaw and the collarbone. It is formed where a superior root from C1 — which hitches a ride on the hypoglossal nerve before peeling away from it — meets an inferior root descending from C2 and C3. From the loop, short twigs drop into the strap muscles that steady and depress the hyoid bone and larynx during swallowing and speech. Its name simply means 'loop of the neck', and its position makes it a useful landmark: it lies superficial to the great vessels and deep to the straps it supplies.