Omohyoid (Superior Belly)
Neck · Head & Neck
The omohyoid is a two-bellied infrahyoid muscle joined by an intermediate tendon that is held in place against the clavicle by a fascial sling. The superior belly is the upper of these two parts: it ascends from the intermediate tendon to insert on the inferior border of the body of the hyoid bone. Together with the inferior belly it depresses and steadies the hyoid bone, and the fascial sling anchoring the intermediate tendon allows the muscle to act as a fixed strut during this action. The superior belly is supplied by the superior root of the ansa cervicalis, carrying fibres from C1.
Origin, Insertion, Action & Nerve
Origin
Intermediate tendon (tethered to the clavicle by a fascial sling)
Insertion
Inferior border of the body of the hyoid bone
Action
Depresses and steadies the hyoid bone
Nerve
Superior root of the ansa cervicalis (C1)
Attachments explained
The Omohyoid (Superior Belly) is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Intermediate tendon (tethered to the clavicle by a fascial sling)
Insertion
Inferior border of the body of the hyoid bone
Action & function
When the Omohyoid (Superior Belly) contracts, it produces the following movement: Depresses and steadies the hyoid bone.
As part of the Neck group of the Head & Neck, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Omohyoid (Superior Belly) receives its nerve supply from the Superior root of the ansa cervicalis (C1). This nerve carries fibres from spinal segment(s) C1.
Because a muscle can only contract when its nerve is intact, injury to the Superior root of the ansa cervicalis or to its spinal roots (C1) can weaken or paralyse the Omohyoid (Superior Belly), impairing the movements it normally produces (depresses and steadies the hyoid bone). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Omohyoid (Superior Belly) (the OIANS method)
Study the superior belly as the visible upper limb of the omohyoid, running from the tethered intermediate tendon up to the hyoid bone. Its role of depressing and steadying the hyoid makes sense only once you appreciate the fascial sling that pins the intermediate tendon to the clavicle, giving the belly a fixed point to pull against. Picture that sling first, then the belly rising from it to the hyoid.
For the nerve, note the split within the ansa cervicalis: the superior belly is supplied specifically by the superior root, which carries C1 fibres, whereas the inferior belly is reached by the ansa itself from C2 to C3. Keeping the superior root paired with the superior belly is a precise detail that examiners like to test.
Frequently asked questions
Where is the Omohyoid (Superior Belly) located?
The Omohyoid (Superior Belly) is a muscle of the Neck group, located in the Head & Neck.
What is the origin of the Omohyoid (Superior Belly)?
Intermediate tendon (tethered to the clavicle by a fascial sling)
What is the insertion of the Omohyoid (Superior Belly)?
Inferior border of the body of the hyoid bone
What movements does the Omohyoid (Superior Belly) produce?
Depresses and steadies the hyoid bone
What nerve supplies the Omohyoid (Superior Belly)?
Superior root of the ansa cervicalis (C1)
Is the Omohyoid (Superior Belly) free to study in OIANS?
The Omohyoid (Superior Belly) is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Head & Neck is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
Study the Omohyoid (Superior Belly)
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