thyrohyoid muscle

It does not innervate the thyrohyoid muscle, which receives its innervation from the ventral root of C1.

The thyrohyoid muscle is a small, quadrilateral muscle appearing like an upward continuation of the sternothyreoideus.

It is a branch of the superior thyroid artery and it runs along the lower border of the hyoid bone beneath the thyrohyoid muscle.

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.