Omohyoid
Musculus omohyoideus
Also known as: omohyoideus
A long, slender two-bellied infrahyoid muscle running from the scapula to the hyoid. Its intermediate tendon is tethered to the clavicle.
Overview
The inferior belly arises from the superior border of the scapula near the suprascapular notch and crosses the posterior triangle. Deep to SCM it becomes an intermediate tendon, held down to the clavicle by a fascial sling. The superior belly then ascends to the lower border of the body of the hyoid, lateral to sternohyoid. Omohyoid divides the posterior triangle into the occipital and supraclavicular (subclavian) triangles. It divides the anterior triangle into the carotid and muscular triangles.
It depresses, retracts and steadies the hyoid. It is also said to tense the carotid sheath, which may help keep the internal jugular vein open during deep inspiration. Its intermediate tendon crosses the internal jugular vein, a landmark for the jugulo-omohyoid lymph node, which drains the tongue.
Parts & subdivisions
- Inferior bellySuperior border of the scapula → intermediate tendon. Crosses the posterior triangle.
- Superior bellyIntermediate tendon → body of the hyoid.
Anatomy
- Origin
Superior border of the scapula, near the suprascapular notch.
- Insertion
Inferior border of the body of the hyoid bone.
- Action
Depresses, retracts and stabilises the hyoid.
- Innervation
Ansa cervicalis (cervical plexus).
- Nerve roots
C1–C3
- Arterial supply
Superior thyroid and lingual arteries (superior belly); transverse cervical and suprascapular arteries (inferior belly).
- Relations
Its intermediate tendon lies over the internal jugular vein deep to SCM. The jugulo-omohyoid lymph node lies at this crossing.
Function
- Depresses and steadies the hyoid
- May tense the carotid sheath and keep the internal jugular vein open
Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.