What is the Digastric Muscle and What Does it Do?

Learn more about the function, health and purpose of the Digastric Muscle

What is the Digastric Muscle?

The digastric muscle (also digastricus) (named digastric as it has two ‘bellies’) is a small muscle located under the jaw. The term “digastric muscle” refers to this specific muscle.

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It lies below the body of the mandible, and extends, in a curved form, from the mastoid process to the symphysis menti. It belongs to the suprahyoid muscles group.

What is the Function of the Digastric Muscle?

The digastric muscle is involved in any complex jaw action such as speaking, swallowing, chewing and breathing.

Digastric Muscle Structure

The digastricus (digastric muscle) consists of two muscular bellies united by an intermediate rounded tendon.

The two bellies of the digastric muscle have different embryological origins, and are supplied by different cranial nerves.

Each person has a right and left digastric muscle. In most anatomical discussions, the singular is used to refer to a muscle, even when each person actually has two of that muscle—one on the right side, and another on the left.

For example, we speak of the deltoid, even though there is one deltoid in each shoulder. Likewise, we speak of the digastric even though there is a right and left digastric muscle.

What Causes Digastric Muscle Pain?

The posterior belly is connected to the facial nerve. The anterior belly is connected to the trigeminal nerve, which connects to different parts of the face and jaw than the facial nerve.

Thus, any tension in either part of the muscle can send pain impulses through many parts of the face and jaw.

What is the Digastric Muscle Attached to?

The digastric muscle stretches between the mastoid process of the cranium to the mandible at the chin, and part-way between, it becomes a tendon which passes through a tendinous pulley attached to the hyoid bone. It originates from the second pharyngeal arch.

What is the Origin of the Digastric Muscle?

The origin of the digastric muscle is the anterior belly – digastric fossa (mandible); posterior belly – mastoid process of temporal bone.

What is the Insertion of the Digastric Muscle?

The Insertion of the Digastric Muscle is the Intermediate tendon (hyoid bone).

Digastric Muscle Blood Supply

The Digastric Muscle Blood Supply is the anterior belly – Submental branch of facial artery; posterior belly – occipital artery.

Digastric Muscle Innervation

The mylohyoid nerve of the inferior alveolar nerve of the mandibular nerve of the trigeminal nerve innervates the anterior belly of the digastric muscle, and the facial nerve innervates the posterior belly of the digastric muscle.

Digastric Muscle

Now that you understand the Digastric Muscle, learn more about the TFL, obliques and abductors.