Lateral pterygoid muscle
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View Frank Gaillard's current disclosuresAt the time the article was last revised Tea Elliott had no financial relationships to ineligible companies to disclose.
View Tea Elliott's current disclosures- Lateral pterygoid
- Pterygoideus externus
- External pterygoid muscle
The lateral pterygoid muscle, also known as pterygoideus externus or external pterygoid muscle, is one of the muscles of mastication.
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Summary
origin: superior head from the infratemporal surface and the infratemporal crest of the greater wing of the sphenoid bone. Inferior head from lateral surface of the lateral pterygoid plate
insertion: pterygoid fovea on the anterior neck of the mandible
innervation: nerve to lateral pterygoid, a branch of the anterior division of the mandibular division of the trigeminal nerve
action: opening of the mouth, retrusion of the temperomandibular joint, side-to-side movement of the jaw 1
Gross anatomy
The lateral pterygoid is a short and thick muscle with a somewhat conical form. It extends almost horizontally, posteriorly, and laterally between the infratemporal fossa and the condyle of the mandible. It has two heads: an upper (superior) and a lower (inferior).
The superior part arises from the lower part of the lateral surface of the greater wing of the sphenoid bone and the infratemporal crest. It inserts into the temporomandibular joint capsule and the temporomandibular disc.
The inferior part arises from the lateral surface of the lateral pterygoid plate and inserts into a depression in front of the neck of the condyle of the mandible, the pterygoid fovea 1.
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Innervation
The muscle is supplied by the paired nerves to lateral pterygoid (one for each head), which arise deep to the muscle from the anterior division of the mandibular nerve (CN V3).
Action
The superior part is active during retrusion (opposite of protrusion) and ipsilateral jaw movement. It is also essential in pulling the capsule and disc forward during mouth opening, thereby maintaining normal relationship between the condyle of the mandible and the disc of the tempoeromandibular joint.
The inferior part is responsible for opening of the mouth, protrusion, and contralateral jaw movement.
Hyperactivity of the lateral pterygoid muscle has been described in temperomandibular joint internal derangement, especially with longstanding anterior displacement of the disc without recapture. Thickening of the tendon (inferior part) can give rise to the "double disc sign".
Variant anatomy
Anatomical variants of the lateral pterygoid include:
fusion with temporalis or digastric muscle
-
variation in number of heads
three headed variant with an inner head originating at the greater wing of the sphenoid
single headed variant
-
variation in number of insertions
three insertion sites: articular disc, TMJ capsule, condyle of the mandible
single insertion site at the condyle only
References
- 1. Susan Standring. Gray's Anatomy. (2020) ISBN: 9780702077050 - Google Books
- 2. Anatomy of the Human Body. (2000) ISBN: 1587341026 - Google Books
- 3. Sommer O, Aigner F, Rudisch A et al. Cross-Sectional and Functional Imaging of the Temporomandibular Joint: Radiology, Pathology, and Basic Biomechanics of the Jaw. Radiographics. 2003;23(6):e14. doi:10.1148/rg.e14 - Pubmed
- 4. Tomas X, Pomes J, Berenguer J et al. MR Imaging of Temporomandibular Joint Dysfunction: A Pictorial Review. Radiographics. 2006;26(3):765-81. doi:10.1148/rg.263055091 - Pubmed
- 5. R. Shane Tubbs, Mohammadali M. Shoja, Marios Loukas. Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. (2016) ISBN: 9781118430354 - Google Books
Incoming Links
- Deep temporal nerves
- Infratemporal fossa
- Greater wing of sphenoid
- Muscles of mastication
- Motor nucleus of the trigeminal nerve
- Masticatory muscle hypertrophy
- Accessory meningeal artery
- Condylar process of the mandible
- Temporomandibular joint disc
- Maxillary artery
- Oropharyngeal (p16-negative) cancer (staging)
- Temporomandibular joint
- Medial pterygoid muscle
- Pterygomandibular space
- Lingual nerve
- Inferior alveolar nerve
- Masseteric nerve
- Pterygoid processes
- Trigeminal nerve
- Pterygoid fovea
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