Sternohyoideus
The Sternohyoideus originates from the sternum. It inserts in the hyoid bone. This muscle depresses() the hyoid bone and acts in speech and swallowing movements. In order for one to get to this muscle, they must reflect the muscle that is directly under the skin of the neck and get to the deep, underlying muscles which is where the Sternohyoideus is located.
Sternothyroideus
The sternothyroideus originates from the manubrium and inserts thyroid cartilage. The action of this muscle is to depress the thyroid cartilage and to depress the larynx. In order for one to get to this muscle, they must reflect the muscle that is directly under the skin of the neck and get to the deep, underlying muscles which is where the sternothyroideus is located.
Sternomastoideus
The sternomastoideus originates from the medial portion of the clavicle and inserts on the mastoid process of the termporal bone, and the superior nuchal line. The action of this muscle is to flex the head and chests, as well as inclining the head from side to side. To find the sternomastoideus first find the sternothyroideus and sternohyoideus and underneath them is the sternomastoideus.