Muscle · Neck

Sternothyroid

Musculus sternothyroideus

The strap muscle that lies directly beneath the sternohyoid, shorter and wider than it, running from the back of the breastbone up to the thyroid cartilage — the shield of cartilage you feel as the Adam's apple. Unlike its neighbour it stops at the larynx rather than continuing to the hyoid, so its pull lowers the whole voice box after swallowing has raised it. It lies flat across the front of the lobes of the thyroid gland, which is why the gland sits behind a layer of muscle rather than immediately under the skin. Together with the thyrohyoid above it, it forms a two-stage chain from breastbone to larynx to hyoid.