The medial pterygoid muscle (or internal pterygoid muscle) is a thick, quadrilateral muscle of the
face. It is supplied by the
mandibular branch of the
trigeminal nerve
In neuroanatomy, the trigeminal nerve (literal translation, lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for Sense, sensation in the face and motor functions ...
(V). It is important in
mastication (chewing).
Structure
The medial pterygoid muscle consists of two heads. The bulk of the muscle arises as a deep head from just above the medial surface of the
lateral pterygoid plate. The smaller, superficial head originates from the
maxillary tuberosity and the pyramidal process of the
palatine bone.
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
In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla).
The jawbone i ...
, 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.
Nerve supply
The medial pterygoid muscle is supplied by the
medial pterygoid nerve, a branch of the
mandibular nerve
In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth Cranial nerves, cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which ...
, itself a branch of the
trigeminal nerve
In neuroanatomy, the trigeminal nerve (literal translation, lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for Sense, sensation in the face and motor functions ...
(V). This also supplies the
tensor tympani muscle and the
tensor veli palatini muscle. The medial pterygoid nerve is a main trunk from the mandibular nerve, before the division of the trigeminal nerve - this is unlike the
lateral pterygoid muscle, and all other muscles of
mastication which are supplied by the anterior division of the mandibular nerve.
Function
The medial pterygoid muscle has functions including elevating the mandible (closing the mouth), protruding the mandible,
mastication (especially for when the
maxillary teeth and the
mandibular teeth are close together),
and excursing the mandible (contralateral excursion occurs with unilateral contraction).
Additional images
File:Medial pterygoid muscle animation small.gif, Position of medial pterygoid muscle (red).
File:Gray169.png, Left palatine bone. Posterior aspect. Enlarged.
File:Gray177.png, Mandible. Inner surface. Side view.
File:Gray510.png, Plan of branches of internal maxillary artery.
File:Gray778.png, Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion.
File:Gray782 updated.png, Mandibular division of trifacial nerve, seen from the middle line.
File:Gray1031.png, Muscles of the pharynx, viewed from behind, together with the associated vessels and nerves.
File:Slide6che.JPG, Deep dissection. Anterior view.
File:Medial pterygoid muscle.jpg, Medial pterygoid muscle
File:Medial pterygoid muscle 2.jpg, Medial pterygoid muscle
File:Slide7rr.JPG, Medial pterygoid muscle
File:Slide1vv.JPG, Medial pterygoid muscle
File:Slide13dddd.JPG, Medial pterygoid muscle
File:Slide7cece.JPG, Infratemporal fossa. Lingual and inferior alveolar nerve. Deep dissection. Anterolateral view
References
External links
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Muscles of the head and neck