Posterior belly of digastric

The posterior belly of the digastric (Latin: venter posterior musculi digastrici) is one of two bellies composing the digastric muscle. The digastric is one of the muscles of the neck, and its other belly is known as the anterior belly. As the digastric is located above the hyoid bone, it is classified as the suprahyoid neck muscle. It also belongs to the anterior neck muscles. The posterior belly is the largest of both bellies, and it develops from the second pharyngeal arch.

Origin

The posterior belly originates from the mastoid notch that is located on the temporal bone medial to the mastoid process.

Insertion

From the origin site, the posterior belly of the digastric stretches forward and downward. Fibers of this belly form the intermediate tendon that attaches to the hyoid bone.

Action

Upon activation, the posterior belly of the digastric elevates the hyoid bone or depresses the lower jaw.

Innervation

The posterior belly of the digastric muscle is innervated by the digastric branch of the facial nerve (CN VII).

Blood supply

The posterior belly receives arterial blood supply from the occipital and posterior auricular arteries from the external carotid artery.