Digastric muscle - Oral cavity - Muscles - e-Anatomy
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Digastric muscle

Musculus digastricus

  • Latin synonym: Musculus biventer mandibulae
  • Related terms: Digastric

Definition

Muhammad A. Javaid

Digastric muscle

Origin

Anterior belly - digastric fossa (mandible); posterior belly - mastoid process of temporal bone

Insertion

Intermediate tendon (hyoid bone)

Innervation

Anterior belly - mandibular division of the trigeminal(CN V) via the mylohyoid nerve; posterior belly -facial nerve (CN VII)

Action

Opens the jaw, raises the hyoid bone

The digastric muscle is a small paired muscle of the suprahyoid group, located beneath the mandible. It has two muscular bellies (anterior and posterior) connected by an intermediate tendon that is anchored to the hyoid bone.

Parts, Attachments, and Nerve Supply

Part

Origin

Insertion

Nerve Supply

Anterior belly

Digastric fossa on inner surface of mandible

Intermediate tendon (attached to body and greater horn of hyoid via a fibrous loop)

Mylohyoid nerve (branch of inferior alveolar nerve, CN V3)

Posterior belly

Mastoid notch of temporal bone

Intermediate tendon

Facial nerve (CN VII)

Actions

  • When mandible is fixed: Elevates the hyoid bone (important during swallowing).

  • When hyoid is fixed: Depresses the mandible, helping to open the mouth.

Relations

  • Lies superficial to the mylohyoid and inferior to the mandible.

  • Forms part of the submandibular triangle, with the submandibular gland located between its two bellies.

  • The posterior belly helps define the carotid triangle, while the anterior belly borders the submental triangle.

References

  • Tranchito EN, Bordoni B. Anatomy, Head and Neck, Digastric Muscle. [Updated 2024 Jan 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK544352/

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