0 relating to the thyroid cartilage (= part of the larynx) and the hyoid arch, which links the base of the tongue to the skull: --
It descends to the thyrohyoid membrane, piercing it in company with the superior laryngeal artery, and is distributed to the mucous membrane of the larynx.
Note that the thyrohyoid muscle, which is also an infrahyoid muscle, is innervated by cervical spinal nerve 1 via the hypoglossal nerve.
Its superior belly serves as the most lateral member of the infrahyoid muscles, located lateral to both the sternothyroid and thyrohyoid muscles.
The four infrahyoid muscles are; the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles.
It is a branch of the superior thyroid artery and it runs along the lower border of the hyoid bone beneath the thyrohyoid muscle.