- Plantaris muscle
Name = Plantaris muscle
Latin = musculus plantaris
GraySubject = 129
GrayPage = 483
Caption = The mucous sheaths of the tendons around the ankle. Medial aspect. (Plantaris labeled at bottom right.)
Origin = Lateral supracondylar ridge of
femurabove lateral head of gastrocnemius
Tendo calcaneus(medial side, deep to gastrocnemiustendon)
Plantar flexes footand flexes knee
Tibialis anterior muscle
DorlandsPre = m_22
DorlandsSuf = 12550213
Plantaris is a
vestigial structureand one of the superficial muscles of the posterior crural compartmentof the leg.
It is innervated by the
tibial nerve(S1, S2).
Origin and insertion
It arises from the inferior part of the
lateral supracondylar lineof the femurat a position slightly superior to the origin of the lateral head of gastrocnemius.
Also, it may arise from the
oblique popliteal ligament.
Passing inferomedially posterior to the
knee joint, it becomes tendinous while passing distally to insert into the tendo calcaneus, or occasionally separately inserting into the medial side of the calcaneus.
Plantaris acts to weakly:
plantarflexthe ankle joint
*flex the knee joint
Plantaris may also provide proprioceptive feedback information to the central nervous system regarding the position of the foot. The unusually high density of proprioceptive receptor end organs supports this notion.
Its motor function is so minimal that its long tendon can readily be harvested for reconstruction elsewhere with little functional deficit. "Often mistaken for a nerve by freshman medical students, the muscle was useful to other primates for grasping with their feet. It has disappeared altogether in 9 percent of the population." [cite journal |last=Selim |first=Jocelyn |year=2004 |month=June |title=Useless Body Parts |journal=Discover |volume=25 |issue=6 |url=http://discovermagazine.com/issues/jun-04/features/useless-body-parts/ |accessdate=2007-02-18 ]
* [http://www.ptcentral.com/muscles/musclelegs.html#plantaris PTCentral]
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