What is ansa cervicalis?
The ansa cervicalis is a loop in the cervical plexus consisting of fibres from the first three cervical nerves. Fibres from C-1 spinal nerves accompany the hypoglossal nerve for a short distance, leaving it as the superior root of the ansa cervicalis. Fibres from a loop between the C-2 and C-3 spinal nerves form the inferior root of the ansa cervicalis. Most commonly, the roots merge, forming the ansa cervicalis, which gives rise to branches innervating infrahyoid muscles, execpt for the thyrohyoid muscle which is innervated by C1 via the hypoglossal nerve(CN XII) and the the ansa cervicalis. Hope that helps.
