Bilateral clavicular attachment of omohyoid muscle

An anomalous muscle clinging around the inferior belly of omohyoid muscle

Sternohyoid, sternothyroid, omohyoid and thyrohyoid muscles belong to a group of muscles called infrahyoid muscles. A few variations of these muscles and additional muscles in this area have been reported. We report an anomalous muscle in this area. The anomalous muscle took its origin from the posterior surface of the manubrium sterni and was inserted to the posterior surface of the clavicle. This muscle was 6 cm long and interestingly, it made a loop, which was clinging on to the inferior belly of omohyoid posteriorly, superiorly and anteriorly. The muscle was situated between the lower end of sternocleidomastoid and the carotid sheath. It was supplied by ansa cervicalis. Knowledge of this muscle could be useful in surgeries like removal of cervical rib, and cervical lymph node clearance. Hypertrophy of this muscle might compress the internal jugular vein.