Muscle · Neck

Geniohyoid

Musculus geniohyoideus

A short strap of muscle lying just under the tongue, running straight back from the inside of the chin to the front of the hyoid bone. The two of them sit side by side across the midline, immediately above the mylohyoid sheet, and their job is to haul the hyoid bone forwards and upwards — the movement that pulls the top of the airway open at the start of a swallow. Its supply is an oddity worth knowing: the fibres come from the first cervical spinal nerve but travel to the muscle inside the hypoglossal nerve, so the nerve of the tongue delivers the supply of a neck muscle. When the hyoid is held down from below, the same pull works in reverse and helps drop the jaw open.