Ansa cervicalis
The ansa cervicalis ( neck nerve loop ), - according to the previous nomenclature but still widely used Ansa cervicalis profunda - is a nerve loop of the ventral (abdominal) branches of the cervical vertebrae segments C1 to C3. Therefore it belongs to the cervical plexus .
The nerve loop is formed from an upper root ( superior radix ) from the nerve fibers of segments C1 and C2 and a lower root ( inferior radix ) from C2 and C3.
The ansa cervicalis lies below the sternocleidomastoid muscle and in its course crosses the internal jugular vein and the anterior scalene muscle . In the carotid trigonum , it attaches to the hypoglossal nerve , but these do not exchange fibers with one another (hence the ansa cervicalis profunda is also called ansa hypoglossi).
The ansa cervicalis supplies the following sub- hyoid muscles (infrahyoid muscles):
The thyrohyoid muscle , which is also a representative of the lower hyoid bone muscles, is innervated by the thyrohyoid ramus from the superior ansae cervicalis profundae radix .
The superficial ansa cervicalis superficialis , on the other hand, lies on the sternocleidomastoid muscle and below the platysma . It is formed by the anastomosis between the ramus colli of the nervus facialis and the nervus transversus colli (ventral branch of the spinal nerve from C3).
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- Michael Schünke , Erik Schulte , Udo Schumacher : Prometheus. Anatomy Learning Atlas. Head, Neck and Neuroanatomy . 4th edition. Thieme, Stuttgart 2015, ISBN 978-3-13-139544-3 .