The sternohyoid muscle is one of the paired
strap muscles of the
infrahyoid muscles. The muscle is directed superomedially from its origin to its insertion. The two muscles are separated by a considerable interval inferiorly, but usually converge by their mid-point and remain proximal until their superior insertion.
Origin It arises from the posterior aspect of the medial end (sternal extremity of the
clavicle, the
posterior sternoclavicular ligament, and (the superoposterior portion of) the
manubrium of
sternum. It inserts onto the inferior border of the body of
hyoid bone.
Nerve supply The sternohyoid muscle receives motor innervation from branches of the
ansa cervicalis (which are ultimately derived from
cervical spinal nerves C1-C3).
Relations The muscle is situated lateral to the
trachea.
Variations The muscle may be absent, doubled, exhibit a clavicular slip (the cleidohyoideus), or interrupted by a tendinous intersection; it sometimes presents a transverse
tendinous inscription just distal to its origin.
Actions/movements The muscle depresses the hyoid bone when the bone is in an elevated position. == Function ==