The sternohyoid muscle is a long, thin muscle located along the entire length of the front of the neck. This muscle is connected by tendons — strong, flexible tissue that usually connects muscle to bone — to the hyoid bone at its top end, and connected to the sternum at its lower end. The hyoid is a bone near the top of the throat. The sternum is the bone at the front of the rib cage.
Due to its location, the sternohyoid is useful for several functions, including depression (lowering) of the hyoid bone, head and neck movement, and speech.
The sternohyoid muscle's main function is the depression of the hyoid bone. The hyoid bone is located below the mandible, or lower jaw, and is a "U" shaped bone that is partially responsible for tongue movement and the action of swallowing. The sternohyoid is one of a pair of muscles responsible for this action.
The sternohyoid muscle usually lies along the left side of the trachea, or windpipe, in the throat area. Some individuals may have structural differences in this muscle, and, occasionally, it may be absent.