The Sternohyoid muscle is a long and slender muscle that connects the hyoid bone to the sternum, or breastbone. It is one of the paired muscles in the infrahyoid group, which consists of muscles located below the hyoid bone in the neck region. The Sternohyoid muscle is innervated by the ansa cervicalis and plays an important role in the movement of the hyoid bone. Specifically, it helps to lower the hyoid bone.
Structure
The Sternohyoid muscle is a thin, elongated muscle that originates from the manubrium of the sternum, or breastbone, and inserts into the hyoid bone. It is situated in the neck region, deep to the Sternothyroid muscle and superficial to the Omohyoid muscle.
The Sternohyoid muscle is supplied by the ansa cervicalis, a nerve bundle that arises from the cervical plexus and is formed by the ventral rami of C1-C3 spinal nerves. The ansa cervicalis gives off several branches that innervate the Sternohyoid muscle, as well as other neck muscles such as the Sternothyroid, Omohyoid, and Thyrohyoid muscles.
There are some variations in the origin and insertion of the Sternohyoid muscle that may be seen in some individuals. For example, the muscle may have a separate origin from the manubrium and the first costal cartilage, or it may have a single origin from the manubrium and first costal cartilage. Similarly, the muscle may insert into the hyoid bone alone or in conjunction with the thyroid cartilage. These variations, however, are relatively rare and do not affect the function of the Sternohyoid muscle.
Location
The Sternohyoid muscle is located in the neck region, in the anterior triangle of the neck. It is situated between the clavicle and the hyoid bone, and extends from the manubrium of the sternum to the hyoid bone. The Sternohyoid muscle is surrounded by several other neck muscles, including the Sternothyroid muscle, Omohyoid muscle, and Thyrohyoid muscle.
Function
The Sternohyoid muscle performs several important functions in the neck region. It is responsible for movement of the hyoid bone and larynx, which play a crucial role in speech and swallowing. During speech, the Sternohyoid muscle, along with the Sternothyroid muscle, helps to raise the larynx and hyoid bone, allowing for the production of vocal sounds. During swallowing, the Sternohyoid muscle, along with the Omohyoid muscle and Thyrohyoid muscle, helps to elevate the larynx and hyoid bone, allowing for the passage of food into the esophagus.
In addition to its role in speech and swallowing, the Sternohyoid muscle also helps to stabilize the hyoid bone and larynx during movement of the head and neck. It works in conjunction with other neck muscles to maintain proper alignment of the head and neck, helping to prevent strain and injury.
Clinical Significance
The Sternohyoid muscle is an important muscle in the neck region and plays a crucial role in speech and swallowing. Dysfunction or injury to the Sternohyoid muscle can lead to problems with these functions, including difficulty speaking or swallowing.
One common condition that may affect the Sternohyoid muscle is laryngopharyngeal reflux, or LPR. LPR is a type of acid reflux that occurs when stomach acid travels up the esophagus and into the throat, causing inflammation and irritation of the larynx and pharynx. This can lead to difficulty swallowing and hoarseness of the voice. The Sternohyoid muscle may become weak or damaged as a result of LPR, leading to further difficulties with speech and swallowing.
Another condition that may affect the Sternohyoid muscle is cervical spondylosis, a degenerative condition of the cervical spine. This condition can lead to narrowing of the spinal canal and compression of the spinal cord or nerve roots, resulting in pain and muscle weakness. The Sternohyoid muscle may be affected by cervical spondylosis, leading to difficulty with speech and swallowing.
In addition, the Sternohyoid muscle may be affected by trauma or injury to the neck region, such as a car accident or a sports injury. This can lead to muscle strain or tears, resulting in difficulty with speech and swallowing.
Overall, it is important to maintain the health and function of the Sternohyoid muscle to ensure proper speech and swallowing. Any dysfunction or injury to this muscle should be promptly addressed to prevent further complications.
