The stylohyoid muscle is a small, slender muscle located in the neck region of the human body. It is one of the muscles of the infrahyoid group, which also includes the geniohyoid, thyrohyoid, and omohyoid muscles. These muscles act to stabilize the hyoid bone, a small bone located in the neck that serves as a attachment point for several muscles of the head and neck.
Structure
The stylohyoid muscle is a small, slender muscle located in the neck region of the human body. It is one of the muscles of the infrahyoid group, which also includes the geniohyoid, thyrohyoid, and omohyoid muscles. These muscles act to stabilize the hyoid bone, a small bone located in the neck that serves as a attachment point for several muscles of the head and neck.
The stylohyoid muscle has a triangular shape and is composed of skeletal muscle tissue. It originates from the styloid process, a bony protuberance located on the temporal bone of the skull. The styloid process is a thin, elongated bone that extends inferiorly from the temporal bone and is located just posterior to the ear.
The stylohyoid muscle then travels inferiorly and inserts on the hyoid bone. The hyoid bone is a small, U-shaped bone located in the neck that serves as a attachment point for several muscles of the head and neck. It is located between the mandible and the larynx and is held in place by the muscles of the infrahyoid group.
The stylohyoid muscle is innervated by the facial nerve (CN VII) and receives its blood supply from the stylomastoid branch of the external carotid artery. The facial nerve supplies innervation to the muscles of the face, including the muscles of the mouth and neck. The external carotid artery is a major blood vessel that supplies blood to the head and neck region.
Location
The stylohyoid muscle is located in the neck, posterior to the submandibular gland and anterior to the sternocleidomastoid muscle. It is situated just below the ear and can be palpated by pressing on the area just posterior to the angle of the mandible.
Function
The main function of the stylohyoid muscle is to elevate the hyoid bone and larynx during swallowing and speaking. The hyoid bone and larynx are important structures that play a key role in the function of the pharynx and larynx. The pharynx is a muscular tube that serves as a passageway for air and food, and the larynx is a structure that helps to produce sound during speech.
During swallowing, the stylohyoid muscle and other muscles of the infrahyoid group contract to elevate the hyoid bone and larynx. This helps to open the pharynx and larynx, allowing food and liquids to pass through to the esophagus. The stylohyoid muscle also helps to extend the head and neck during swallowing, which helps to position the pharynx and larynx for swallowing.
In addition, the stylohyoid muscle may contribute to the movements of the mandible during chewing and speaking. The mandible is the lower jaw bone that helps to form the jawline and is responsible for the movement of the jaw during chewing and speaking. The stylohyoid muscle and other muscles of the infrahyoid group may help to stabilize the mandible during these activities.
Clinical significance
The stylohyoid muscle may be involved in a number of clinical conditions. These include:
- Eagle syndrome: This is a rare condition characterized by elongation of the styloid process, which can cause pain and discomfort in the neck, throat, and ears.
- Dysphagia: Difficulty swallowing (dysphagia) can be caused by dysfunction of the stylohyoid muscle or other muscles of the infrahyoid group. Dysphagia can be caused by a number of factors, including neurological disorders, structural abnormalities, and muscle weakness.
- Parapharyngeal abscess: An abscess (collection of pus) in the parapharyngeal space (a space between the pharynx and the mandible) can cause swelling and discomfort in the neck region. The stylohyoid muscle may be involved in the development of this condition.
- Torticollis: This is a condition characterized by abnormal head and neck positioning, often caused by muscle spasm or weakness. The stylohyoid muscle may be involved in the development of torticollis.
