ansa cervicalis

The ansa cervicalis is embedded in the anterior wall of sheath.

Two roots make up the ansa cervicalis.

"Ansa cervicalis."

Superficial to the carotid sheath lies the hypoglossal nerve and ansa cervicalis of the cervical plexus.

The inferior root of the ansa cervicalis, also known as descendens cervicalis, is formed by fibers from spinal nerves C2 and C3.

The omohyoid is innervated by a branch of the cervical plexus, the ansa cervicalis, and mostly acts to stabilise the hyoid bone.

The superior root of the ansa cervicalis is formed from cervical spinal nerve 1 of the cervical plexus.

The ansa cervicalis (or ansa hypoglossi in older literature) is a loop of nerves that are part of the cervical plexus.

Branches from the ansa cervicalis innervate three of the four infrahyoid muscles: the sternohyoid muscle, the sternothyroid muscle, and the omohyoid muscle.

It is innervated by ansa cervicalis, a cervical plexus (C1-3), which joins the hypoglossal nerve for a short distance, and depresses the hyoid and elevates the larynx.

All of the infrahyoid muscles are innervated by the ansa cervicalis from the cervical plexus (C1-C3) except the thyrohyoid muscle, which is innervated by fibres only from the first cervical spinal nerve travelling with the hypoglossal nerve.

In front of the sheath are a few descending filaments from the ansa cervicalis; behind the sheath are the inferior thyroid artery, the recurrent nerve, and the sympathetic trunk; and on its medial side, the esophagus, the trachea, the thyroid gland, and the lower part of the larynx.

Although the inferior belly of the omohyoid is innervated by branches of all three cervical rami (C1-C3) that make up the ansa cervicalis, the superior belly is innervated by the superior root of ansa cervicalis which contains only fibers from the first cervical spinal nerves (C1).