It is a small, quadrilateral shaped muscle that emerges to look like a continuation of the sternothyroid muscle. It takes its origin from the thyroid cartilage, and its insertion lies in the thyrohyal portion of the hyoid bone.
The thyrohyoid works to lower, or depress, the hyoid bone in the throat area, and it also assists in raising the thyroid cartilage. A unique feature of this muscle is that it connects directly to the larynx; other muscles in the group connect below it and thus contribute to downward movement of the larynx. The thyrohyoid muscle connects to the larynx and affects the tension allowed in the vocal folds. In short, the thyrohyoid muscle affects the pitch of the voice by controlling the thyroid cartilage, altering the length in addition to the tension in that area. The position of the larynx in this fashion also affects syllable and vowel production in speech. Being a small muscle surrounded by many others, it has a very specific function in the physiology of the neck.