Anatomy and Structure
- The digastric muscle is a bilaterally paired suprahyoid muscle located under the jaw.
- It consists of two muscular bellies united by an intermediate tendon.
- The posterior belly attaches to the mastoid notch of the temporal bone.
- The anterior belly attaches to the digastric fossa of the mandible.
- The two bellies meet at the intermediate tendon.
- The tendon perforates the stylohyoideus muscle.
- The tendon is embraced by a fibrous sling attached to the hyoid bone.

Innervation
- The anterior belly receives motor innervation from the mylohyoid nerve, a branch of the inferior alveolar nerve.
- The posterior belly is supplied by the digastric branch of the facial nerve.
- The digastric muscle has dual innervation from the mandibular division of the trigeminal nerve (CN V) and the facial nerve (CN VII).

Relations
- The posterior belly is situated posterior to the parotid gland and the facial nerve.
- The digastric muscle divides the anterior triangle of the neck into four smaller triangles: submandibular triangle, carotid triangle, submental triangle, and inferior carotid triangle.
- The digastric muscle plays a role in defining the boundaries of these neck triangles.

Variation
- The intermediate tendon may be absent in some individuals.
- The posterior belly may partly or entirely arise from the styloid process of the temporal bone.
- The digastric muscle may have additional slips connecting it to other muscles.
- The anterior belly may be double or have extra slips passing to the jaw or mylohyoideus.
- The digastric muscle may fuse with the mylohyoid muscle or show variations in its attachment points.

Additional Facts
- The two bellies of the digastric muscle have different embryological origins.
- The mylohyoid nerve is a branch of the inferior alveolar nerve, which is a branch of the mandibular division of the trigeminal nerve (CN V).

Digastric muscle (Wikipedia)

The digastric muscle (also digastricus) (named digastric as it has two 'bellies') is a bilaterally paired suprahyoid muscle located under the jaw. Its posterior belly is attached to the mastoid notch of temporal bone, and its anterior belly is attached to the digastric fossa of mandible; the two bellies are united by an intermediate tendon which is held in a loop that attaches to the hyoid bone. The anterior belly is innervated via the mandibular nerve (cranial nerve V), and the posterior belly is innervated via the facial nerve (cranial nerve VII). It may act to depress the mandible or elevate the hyoid bone.

Digastric muscle
Muscles of the neck. Lateral view.
Front view of neck.
Details
Origin	anterior belly - digastric fossa (mandible); posterior belly - mastoid notch of temporal bone
Insertion	Intermediate tendon (hyoid bone)
Artery	anterior belly - Submental branch of facial artery; posterior belly - occipital artery
Nerve	anterior belly - mandibular division (V3) of the trigeminal (CN V) via the mylohyoid nerve; posterior belly - facial nerve (CN VII)
Actions	Opens the jaw when the masseter and the temporalis are relaxed.
Identifiers
Latin	musculus digastricus
TA98	A04.2.03.002
TA2	2160
FMA	46291
Anatomical terms of muscle [edit on Wikidata]

The term "digastric muscle" refers to this specific muscle even though there are other muscles in the body to feature two bellies.^{[citation needed]}