[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) › Omohyoid [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) # Omohyoid The omohyoid is a two-bellied strap muscle that crosses the neck from the shoulder blade to the hyoid bone; it pulls the hyoid down. Official name: Omohyoid muscle [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=omohyoid&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A two-bellied strap muscle from the shoulder blade to the hyoid, crossing the neck. ## What it does Pulls the hyoid down; a landmark over the carotid sheath. ## Key points - Its intermediate tendon crosses the internal jugular vein about at the level of the [cricoid cartilage](https://durgical.com/en/anatomy/cricoid-cartilage/): the surgical boundary between node levels III and IV - The superior belly divides the anterior triangle into carotid and muscular triangles; the inferior belly divides the posterior triangle into occipital and supraclavicular triangles - Supraomohyoid neck dissection removes levels I–III, the nodes above the point where the muscle crosses the jugular vein ## Key facts **Origin** Inferior belly: superior border of the scapula near the notch **Insertion** Superior belly: body of the hyoid (intermediate tendon held to the [clavicle](https://durgical.com/en/anatomy/clavicle/)) **Action** Depresses the hyoid **Nerve** [Ansa cervicalis](https://durgical.com/en/anatomy/ansa-cervicalis/) (C1–C3) **Blood supply** Transverse cervical and superior thyroid arteries ## Relations **Course** The inferior belly runs forward from the upper border of the [scapula](https://durgical.com/en/anatomy/scapula/) across the lower posterior triangle; the intermediate tendon passes deep to the [sternocleidomastoid](https://durgical.com/en/anatomy/sternocleidomastoid-muscle/); the superior belly then rises almost vertically beside the [sternohyoid](https://durgical.com/en/anatomy/sternohyoid-muscle/) to the [hyoid bone](https://durgical.com/en/anatomy/hyoid-bone/) **Deep** Under the tendon, the [carotid sheath](https://durgical.com/en/anatomy/carotid-sheath/) ([internal jugular vein](https://durgical.com/en/anatomy/internal-jugular-vein/), [common carotid artery](https://durgical.com/en/anatomy/common-carotid-artery/), [vagus nerve](https://durgical.com/en/anatomy/vagus-nerve/)); under the inferior belly, the [scalenes](https://durgical.com/en/anatomy/scalenus-anterior-muscle/), the [brachial plexus trunks](https://durgical.com/en/anatomy/brachial-plexus-trunks/) and the [phrenic nerve](https://durgical.com/en/anatomy/phrenic-nerve/) **Superficial** Sternocleidomastoid over the tendon; [platysma](https://durgical.com/en/anatomy/platysma/) and the investing [cervical fascia](https://durgical.com/en/anatomy/superficial-investing-cervical-fascia/) over the inferior belly **Medial** Sternohyoid, beside the superior belly ## How to find it In surgery the intermediate tendon is found deep to the sternocleidomastoid lying across the internal jugular vein; on neck ultrasound it is the thin band crossing the vein, used to tell level III from level IV. ## On imaging On ultrasound and CT the intermediate tendon is the thin band crossing over the internal jugular vein deep to the sternocleidomastoid; surgeons use it to separate node levels III and IV, while radiologists use the lower border of the cricoid. In the supraclavicular region the inferior belly crosses superficial to the [brachial plexus](https://durgical.com/en/anatomy/roots-of-brachial-plexus/), a landmark during ultrasound-guided blocks. ## Clinical notes - Supraomohyoid (selective) neck dissection is typical for cancers of the oral cavity, whose lymph drains first to levels I–III - Branches of the ansa cervicalis to both bellies run on the carotid sheath, so the muscle helps find the ansa during neck surgery - In supraclavicular exposure of the brachial plexus the inferior belly is met crossing the lower posterior triangle and is retracted or divided to reach the plexus trunks and the scalene muscles ## Development One of the strap muscles, formed from the premuscle mass continuous with the [tongue](https://durgical.com/en/anatomy/tongue/) 's and supplied by the upper cervical nerves that enter it early (ansa cervicalis). ## Memory aid Omos is Greek for shoulder: the omohyoid runs from the shoulder blade to the hyoid. ## Test yourself Think of the answer, then tap the question to see it. ## Which node levels does the omohyoid tendon separate where it crosses the internal jugular vein? Levels III and IV: the intermediate tendon crosses the vein at about the level of the cricoid cartilage. ## How do the two bellies of the omohyoid subdivide the neck triangles? Superior belly: anterior triangle into carotid and muscular triangles; inferior belly: posterior triangle into occipital and supraclavicular. ## Which node levels does a supraomohyoid neck dissection remove, and for which cancers is it typical? Levels I–III, above where the omohyoid crosses the jugular vein; typical for oral cavity cancers, which drain first to these levels. ## What is the nerve supply of the omohyoid? The ansa cervicalis (C1–C3), whose branches run on the carotid sheath, so the muscle helps find the ansa in neck surgery. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/omohyoid-muscle/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** musculus omohyoideus TA2 2169 **Official Spanish (DeCS)** Músculo omohioideo **English (TA2)** Omohyoid muscle ## Related - [Ansa cervicalis](https://durgical.com/en/anatomy/ansa-cervicalis/) Sources: Terminologia Anatomica (TA2); [Anatomy, Head and Neck: Anterior Cervical Region](https://www.ncbi.nlm.nih.gov/books/NBK557475/); [Anatomy, Head and Neck, Neck](https://www.ncbi.nlm.nih.gov/books/NBK542313/); Anatomy of the Human Body (20th ed.): Development of the Muscles (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/omohyoid-muscle/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/omohyoid-muscle/