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| Thyrohyoid muscle | |
|---|---|
 Muscles of the neck. Lateral view. (Thyrohyoideus labeled center-left.) | |
 Muscles of the neck. Anterior view. (Thyrohyoideus visible center-left.) | |
| Details | |
| Origin | Thyroid cartilage of larynx |
| Insertion | Hyoid bone |
| Artery | Superior thyroid artery |
| Nerve | First cervical nerve (C1) via hypoglossal nerve |
| Actions | Elevates thyroid and depresses the hyoid bone |
| Identifiers | |
| Latin | Musculus thyrohyoideus |
| TA | A04.2.04.007 |
| FMA | 13344 |
| Anatomical terms of muscle | |
The thyrohyoid muscle is a small skeletal muscle on the neck which depresses the hyoid and elevates the larynx.
Skeletal muscle is one of three major muscle types, the others being cardiac muscle and smooth muscle. It is a form of striated muscle tissue, which is under the voluntary control of the somatic nervous system. Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons.
The neck is the part of the body, on many vertebrates, that separates the head from the torso. It contains blood vessels and nerves that supply structures in the head to the body. These in humans include part of the esophagus, the larynx, trachea, and thyroid gland, major blood vessels including the carotid arteries and jugular veins, and the top part of the spinal cord.
The larynx, commonly called the voice box, is an organ in the top of the neck of tetrapods involved in breathing, producing sound, and protecting the trachea against food aspiration. The larynx houses the vocal folds, and manipulates pitch and volume, which is essential for phonation. It is situated just below where the tract of the pharynx splits into the trachea and the esophagus. The word larynx comes from a similar Ancient Greek word.
Contents
This quadrilateral muscle appearing like an upward continuation of the sternothyreoideus. It belongs to the infrahyoid muscles group.
The infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. The four infrahyoid muscles are: the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles.
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.
The thyroid cartilage is the largest of the nine cartilages that make up the laryngeal skeleton, the cartilage structure in and around the trachea that contains the larynx. It does not completely encircle the larynx; only the cricoid cartilage does.
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra (C3) behind.
It is innervated by thyrohyoid branch of C1 nerve. This nerve branches from the first cervical nerve as it joins the hypoglossal nerve (12th Cranial Nerve) for a short distance. This is the only exception in the infrahyoid muscles, or strap muscles, that is not innervated by ansa cervicalis [1] .
The hypoglossal nerve is the twelfth cranial nerve, and innervates all the extrinsic and intrinsic muscles of the tongue, except for the palatoglossus which is innervated by the vagus nerve. It is a nerve with a solely motor function. The nerve arises from the hypoglossal nucleus in the brain stem as a number of small rootlets, passes through the hypoglossal canal and down through the neck, and eventually passes up again over the tongue muscles it supplies into the tongue. There are two hypoglossal nerves in the body: one on the left, and one on the right.
The ansa cervicalis is a loop of nerves that are part of the cervical plexus. It lies superficial to the internal jugular vein in the carotid triangle. Its name means "handle of the neck" in Latin.
