The omohyoid muscle is a flat muscle belonging to the infrahyoid muscle group. It is critical to neck surgeries, particularly in the case of lymph node metastasis. The omohyoid comprises of two bellies, superior and inferior, and are joined through an inter-muscular tendon. This tendon obliquely passes through the lateral cervical area, supported by a connective tissue that prevents the internal jugular vein from constricting under undue pressure. The inferior belly of the muscle bisects the neck's posterior triangle into two parts, known as the occipital triangle, which is located in the upper part, and the subclavian triangle, which is located in the lower part. The superior belly, on the other hand, bisects the neck's anterior triangle into a carotid triangle, located in the upper part, and a muscular triangle, located in the lower part. The omohyoid muscle is closely connected to the scalpula, and obliquely connected to the hyoid bone. The variations of this muscle in different cases may include double muscles or an absence of it. In some cases, one of the two bellies may be missing, or one belly may be present twice. The muscle may also originate from clavicle in some cases.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Omohyoid