Sternocleidomastoid is an important muscle of head and neck lying in close proximity to the vital structures like spinal accessory nerve, external jugular vein, carotid sheath with its contents, greater auricular nerve, facial and lingual veins, cervical plexus, vagus nerve, ansa cervicalis etc. It originates as two heads, one from the superolateral part of manubrium sterni in form of a tendon (sternal head) and another from medial one-third of superior surface of clavicle which is a musculotendinous structure (Clavicular head). The muscle is inserted into lateral aspect of mastoid process with the help of thick tendon and into lateral half of superior nuchal line by a thin aponeurosis.
