Origin: Thyroid cartilage
Insertion: Hyoid bone
Nerve: Posterior interosseous nerve (C7, C8)
Action: Extends index finger, wrist
The Thyreohyoideus (Thyrohyoid muscle) is a small, quadrilateral muscle appearing like an upward continuation of the Sternothyreoideus. It arises from the oblique line on the lamina of the thyroid cartilage, and is inserted into the lower border of the greater cornu of the hyoid bone.