The digastric muscle is a small but important muscle located in the neck region. It is responsible for a number of important functions, including helping to move the mandible (lower jaw) during chewing and swallowing, and aiding in the creation of sound during speech. Despite its small size, the digastric muscle plays a critical role in maintaining proper function of the mouth and neck.
Structure of Digastric muscle
The digastric muscle is a paired muscle located in the front of the neck. It is responsible for elevating and depressing the mandible, which is the lower jaw bone. The digastric muscle consists of two heads: the anterior belly and the posterior belly.
Anterior Belly
The anterior belly of the digastric muscle is a thin, triangular muscle that arises from the inner surface of the mandible. It is attached to the digastric fossa, which is a depression on the inner surface of the mandible.
The anterior belly runs upwards and backwards, and it is connected to the hyoid bone by the digastric tendon. The hyoid bone is a small, U-shaped bone located in the neck that serves as a point of attachment for several muscles of the neck and larynx.
Posterior Belly
The posterior belly of the digastric muscle is a larger, oval-shaped muscle that arises from the mastoid process, which is a bony projection located on the temporal bone of the skull. The posterior belly runs downward and forward, and it is connected to the hyoid bone by the digastric tendon.
Innervation of the Digastric Muscle
The digastric muscle is innervated by the facial nerve (cranial nerve VII), which is responsible for the control of the muscles of facial expression and the secretion of certain glands. The facial nerve also plays a role in the control of the salivary glands and the lacrimal glands.
Blood Supply to the Digastric Muscle
The digastric muscle is supplied by the facial artery, which is a branch of the external carotid artery. The facial artery runs through the neck and supplies blood to the muscles and tissues of the face and neck.
Where is Digastric muscle located?
The digastric muscle is located in the neck. It is a small, thin muscle that is shaped like a triangle and has two heads: one originates at the mandible (lower jaw bone) and the other originates at the mastoid process (a bony protrusion located behind the ear).
The digastric muscle is responsible for several important functions in the head and neck, including helping to open the mouth, swallowing, and assisting in the movements of the tongue. It is located in the submandibular region, which is an area on the lower part of the face just below the mandible. The digastric muscle is surrounded by other muscles and structures in the neck, including the stylohyoid muscle, the hyoglossus muscle, and the styloid process.
Function
Here are some of the main functions of the digastric muscle:
Opening the Mouth
One of the primary functions of the digastric muscle is to help open the mouth. When the digastric muscle contracts, it pulls the mandible downward and forward, allowing the mouth to open. This is important for activities such as speaking, eating, and breathing.
Swallowing
The digastric muscle also plays a role in the process of swallowing. During swallowing, the digastric muscle helps to elevate the mandible, which in turn helps to close the space between the mandible and the tongue. This helps to form a seal around the food or liquid being swallowed, allowing it to pass smoothly through the pharynx (throat) and into the esophagus.
Tongue Movement
In addition to its role in opening the mouth and swallowing, the digastric muscle also assists in the movement of the tongue. When the digastric muscle contracts, it can help to elevate and retract the tongue, allowing it to move freely in the mouth. This is important for activities such as speaking, eating, and maintaining good oral hygiene.
Other Functions
The digastric muscle may also have other functions in the head and neck, such as helping to maintain proper posture and assisting in the movement of the neck and head. However, these functions are not as well understood as the muscle’s role in opening the mouth, swallowing, and tongue movement.
Clinical Significance
Despite its small size, the digastric muscle can be the source of several clinical problems, and understanding its clinical significance is important for the diagnosis and treatment of these problems.
Pain and Tension
One of the most common clinical issues related to the digastric muscle is pain and tension. The digastric muscle can become tense and painful due to factors such as stress, teeth grinding, and poor posture. This can lead to a condition called myalgia, which is characterized by muscle pain and tenderness. In some cases, the pain and tension in the digastric muscle can be relieved by massaging the area and practicing relaxation techniques, such as deep breathing and meditation.
Trismus
Trismus, also known as lockjaw, is a condition in which the mouth is unable to open fully due to muscle spasm or contracture. The digastric muscle can be involved in this condition, as well as other muscles in the jaw and neck. Trismus can be caused by a variety of factors, including infection, trauma, and radiation therapy. It can lead to difficulty speaking, eating, and maintaining good oral hygiene, and it can also cause discomfort and anxiety. Treatment for trismus may include medications, physical therapy, and in severe cases, surgery.
Dysphagia
Dysphagia is a condition characterized by difficulty swallowing. The digastric muscle plays a key role in the process of swallowing, and any dysfunction in this muscle can contribute to dysphagia. Dysphagia can be caused by a variety of factors, including neurological disorders, structural abnormalities, and cancer. It can lead to malnutrition and dehydration if left untreated, and it can also increase the risk of aspiration pneumonia. Treatment for dysphagia may include medications, diet modifications, and in severe cases, surgery.
Other Clinical Issues
In addition to pain and tension, trismus, and dysphagia, the digastric muscle can be involved in other clinical issues, such as temporomandibular joint disorders (TMJ) and facial asymmetry. TMJ disorders are characterized by pain and dysfunction in the joint that connects the mandible to the skull, and they can be caused by a variety of factors, including muscle imbalances, trauma, and arthritis. Facial asymmetry is a condition in which one side of the face appears differently from the other, and it can be caused by a variety of factors, including muscle imbalances, trauma, and congenital abnormalities. Treatment for these conditions may include medications, physical therapy, and in severe cases, surgery.
