Muscle · Head and neck
Sternohyoid muscle: origin, insertion, action and innervation
The sternohyoid runs from the manubrium and clavicle to the hyoid bone. It pulls the hyoid down after swallowing and is supplied by the ansa cervicalis.
Quick answer
- Latin name
- Musculus sternohyoideus
- Insertion
- Lower border of the body of the hyoid bone, next to the midline
- Action
- Depresses the hyoid bone after it has been raised in swallowing; steadies the hyoid
- Innervation
- Ansa cervicalis (C1–C3), from the cervical plexus
- Blood supply
- Superior thyroid artery
See it on the 3D body
The sternohyoid lit on the 3D neck, as in the neck quiz. Turn the body, peel the layers, tap any structure for its name.
The sternohyoid is a thin, flat strap muscle in the front of the neck that runs from the top of the sternum up to the hyoid bone. It pulls the hyoid back down after you swallow and is supplied by the ansa cervicalis.
Where it is
The sternohyoid lies on each side of the midline, in front of the larynx and the thyroid gland, just under the skin and a thin layer of fascia. It is the most superficial of the infrahyoid muscles, the "strap muscles" that hang below the hyoid bone.
In the front of the neck, the strap muscles sit in two layers:
- Superficial layer: the sternohyoid, close to the midline, and the superior belly of the omohyoid, just lateral to it.
- Deep layer: the sternothyroid below and the thyrohyoid above, which together form a continuous line from the sternum to the hyoid.
The left and right sternohyoids are separated at the bottom by a small gap but come close together near the hyoid. In the midline between them you can feel the larynx and the windpipe. The lower end of each muscle is covered by the sternocleidomastoid.
Origin and insertion
- Origin: the back surface of the manubrium of the sternum, the medial end of the clavicle, and the ligament that joins the two at the sternoclavicular joint.
- Insertion: the lower border of the body of the hyoid bone, beside the midline.
So the muscle starts behind the joint you can feel at the base of the neck and runs straight up, almost vertically, to the hyoid.
What it does
- Depresses the hyoid: when you swallow, the hyoid and larynx are pulled up. The sternohyoid then pulls the hyoid back down to its resting position.
- Steadies the hyoid: holding the hyoid from below gives the suprahyoid muscles a fixed base, so they can pull the jaw down to open the mouth.
The sternohyoid also helps move the hyoid during speech and singing, as the larynx rises and falls with changes in pitch.
Innervation and blood supply
The sternohyoid is supplied by the ansa cervicalis, a loop of fibers from the first three cervical nerves (C1 to C3). The loop lies on or in the carotid sheath and sends branches forward to the strap muscles.
Its blood comes mainly from the superior thyroid artery, the first branch of the external carotid artery, which runs down along the side of the larynx.
How to remember it
- Name as a map: sterno-hyoid, from the sternum to the hyoid. Unlike the sternothyroid, it goes all the way to the hyoid in one step.
- Top layer, middle line: the sternohyoid is the strap you meet first when you cut through the front of the neck, close to the midline.
- Ansa for the straps: three of the four strap muscles take the ansa cervicalis. The fourth, the thyrohyoid, takes C1 fibers that travel with the hypoglossal nerve.
- Up then down: suprahyoid muscles lift the hyoid for swallowing; infrahyoid muscles such as the sternohyoid pull it back down.
Test yourself in the neck quiz.
Frequently asked questions
What does the sternohyoid muscle do?
It depresses the hyoid bone after it has been raised in swallowing, and holds it steady so the suprahyoid muscles can act.
What nerve supplies the sternohyoid?
The ansa cervicalis, which carries fibers from C1 to C3.
Is the sternohyoid a strap muscle?
Yes. It is one of the four infrahyoid or strap muscles, and the most superficial one.
What is the difference between the sternohyoid and the sternothyroid?
The sternohyoid is superficial and reaches the hyoid bone. The sternothyroid lies deeper, is shorter and stops at the thyroid cartilage of the larynx.
