Medial pterygoid muscle

Medial pterygoid muscle
Medial pterygoid
Musculuspterygoideusmedialis.png
The Pterygoidei; the zygomatic arch and a portion of the ramus of the mandible have been removed. (Internus is visible at center bottom.)
Gray783.png
The otic ganglion and its branches. (Pterygoideus internus labeled at bottom right.)
Latin musculus pterygoideus medialis, musculus pterygoideus internus
Gray's subject #109 387
Origin deep head: medial side of lateral pterygoid plate behind the upper teeth
superficial head: pyramidal process of palatine bone and maxillary tuberosity
Insertion    medial angle of the mandible
Artery pterygoid branches of maxillary artery
Nerve mandibular nerve via nerve to medial pterygoid
Actions elevates mandible, closes jaw, helps lateral pterygoids in moving the jaw from side to side
MeSH Pterygoid+Muscles

The medial pterygoid (or internal pterygoid muscle), is a thick, quadrilateral muscle of mastication.

The mandibular branch of the fifth cranial nerve, the trigeminal nerve, innervates the medial pterygoid muscle.

Contents

Origin and insertion

It consists of two heads.

Its fibers pass downward, lateral, and posterior, and are inserted, by a strong tendinous lamina, into the lower and back part of the medial surface of the ramus and angle of the mandible, as high as the mandibular foramen. The insertion joins the masseter muscle to form a common tendinous sling which allows the medial pterygoid and masseter to be powerful elevators of the jaw.

Innervation

Like the lateral pterygoid, and all other muscles of mastication (apart from buccinator which is innervated by the facial nerve (VII)) the medial pterygoid is innervated by the anterior root (motor root) of the mandibular branch of the trigeminal nerve (V). Note: the buccinator muscle is not a muscle of mastication; instead it is classified as a facial muscle.

Actions

Given that the origin is on the medial side of the lateral pterygoid plate and the insertion is from the internal surface of the ramus of the mandible down to the angle of the mandible, its functions include:

  • Elevation of the mandible (closes the jaw)
  • Minor contribution to protrusion of the mandible
  • Assistance in mastication
  • Excursion of the mandible; contralateral excursion occurs with unilateral contraction.

Additional images

External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

Also it elevates mandible.


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  • Medial pterygoid nerve — Nerve: Medial pterygoid nerve Mandibular division of the trigeminus nerve. (Internal pterygoid nerve visible but not labeled.) …   Wikipedia

  • Lateral pterygoid muscle — Infobox Muscle Name = PAGENAME Latin = m. pterygoideus lateralis, m. pterygoideus externus GraySubject = 109 GrayPage = 386 | Caption = The Pterygoidei; the zygomatic arch and a portion of the ramus of the mandible have been removed. (Labeled as… …   Wikipedia

  • pterygoid plate — n either of two vertical plates making up a pterygoid process of the sphenoid bone: a) a broad thin plate that forms the lateral part of the pterygoid process and gives attachment to the lateral pterygoid muscle on its lateral surface and to the… …   Medical dictionary

  • pterygoid nerve — n either of two branches of the mandibular nerve: a) one that is distributed to the lateral pterygoid muscle called also lateral pterygoid nerve b) one that is distributed to the medial pterygoid muscle, tensor tympani, and tensor veli palatini… …   Medical dictionary

  • Pterygoid — (from the Greek for winglike ) can refer to: * Pterygoid processes of the sphenoid bone ** The Lateral pterygoid plate by it * a muscle such as Lateral pterygoid muscle or Medial pterygoid muscle * a branch of the Mandibular nerve …   Wikipedia

  • pterygoid fossa — n a V shaped depression on the posterior part of each pterygoid process that is formed by the divergence posteriorly of its medial and lateral pterygoid plates and that contains the medial pterygoid muscle and the tensor veli palatini …   Medical dictionary

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