Structure and Insertion
- Medial pterygoid muscle consists of two heads
- Deep head arises above medial surface of lateral pterygoid plate
- Superficial head originates from maxillary tuberosity and pyramidal process of palatine bone
- Fibers pass downward, lateral, and posterior
- Insertion joins masseter muscle to form a common tendinous sling

Nerve Supply
- Medial pterygoid muscle is supplied by medial pterygoid nerve
- Medial pterygoid nerve is a branch of mandibular nerve, itself a branch of trigeminal nerve (V)
- Medial pterygoid nerve also supplies tensor tympani muscle and tensor veli palatini muscle
- Medial pterygoid nerve is a main trunk from mandibular nerve, before division of trigeminal nerve
- Unlike lateral pterygoid muscle and other muscles of mastication, which are supplied by anterior division of mandibular nerve

Function
- Medial pterygoid muscle elevates the mandible (closing the mouth)
- Medial pterygoid muscle protrudes the mandible
- Medial pterygoid muscle aids in mastication, especially when maxillary teeth and mandibular teeth are close together
- Medial pterygoid muscle allows contralateral excursion of the mandible with unilateral contraction

Additional Images
- Position of medial pterygoid muscle (red)
- Left palatine bone, posterior aspect, enlarged
- Mandible, inner surface, side view
- Plan of branches of internal maxillary artery
- Distribution of maxillary and mandibular nerves, and submaxillary ganglion

References
- This article incorporates text in the public domain from page 387 of the 20th edition of Gray's Anatomy (1918)
- Wood, W W (1986-05-01). Medial pterygoid muscle activity during chewing and clenching. The Journal of Prosthetic Dentistry. 55 (5): 615–621. doi:10.1016/0022-3913(86)90043-0. ISSN1097-6841. PMID3458914.
- Wikimedia Commons has media related to Medial pterygoid muscles
- MedicalMnemonics.com: 70
- Anatomy diagram: 25420.000-1. Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on 2015-02-26.