Omohyoid (Inferior Belly)

Neck · Head & Neck

Located in the Neck of the Head & Neck, the Omohyoid (Inferior Belly) is a key muscle for anatomy study. Its origin is Superior border of the scapula near the suprascapular notch, and it inserts onto Intermediate tendon (tethered to the clavicle by a fascial sling). Functionally, it depresses and steadies the hyoid bone. Its nerve supply is the Ansa cervicalis (C2–C3).

Origin, Insertion, Action & Nerve

Origin

Superior border of the scapula near the suprascapular notch

Insertion

Intermediate tendon (tethered to the clavicle by a fascial sling)

Action

Depresses and steadies the hyoid bone

Nerve

Ansa cervicalis (C2–C3)

Attachments explained

The Omohyoid (Inferior 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

Superior border of the scapula near the suprascapular notch

Insertion

Intermediate tendon (tethered to the clavicle by a fascial sling)

Action & function

When the Omohyoid (Inferior 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 (Inferior Belly) receives its nerve supply from the Ansa cervicalis (C2–C3). This nerve carries fibres from spinal segment(s) C2, C3.

Because a muscle can only contract when its nerve is intact, injury to the Ansa cervicalis or to its spinal roots (C2, C3) can weaken or paralyse the Omohyoid (Inferior 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 (Inferior Belly) (the OIANS method)

OIANS stands for Origin, Insertion, Action and Nerve, the four facts that uniquely define every skeletal muscle. To learn the Omohyoid (Inferior Belly), work through them in order: picture its origin, trace the muscle to its insertion, reason out the action that shortening between those two points must create, then add the nerve that drives it.

Most students remember the Omohyoid (Inferior Belly) fastest by linking its action back to its attachments rather than memorising each fact in isolation. Once the origin and insertion make sense, the action usually follows logically.