Plantaris muscle

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Plantaris muscle
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The mucous sheaths of the tendons around the ankle. Medial aspect. (Tendon of Plantaris labeled at bottom right.)
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The plantaris is visible under the gastrocnemius.
Latin musculus plantaris
Gray's p.483
Origin Lateral supracondylar ridge of femur above lateral head of gastrocnemius
Insertion Tendo calcaneus (medial side, deep to gastrocnemius tendon)
Artery sural arteries
Nerve tibial nerve
Actions Plantar flexes foot and flexes knee
Antagonist Tibialis anterior muscle
TA A04.7.02.049
FMA FMA:22543
Anatomical terms of muscle

Plantaris is one of the superficial muscles of the posterior crural compartment of the leg.

It is composed of a thin muscle belly and a long thin tendon. It is approximately 5-10 cm long and is absent in 7-10% of the human population. It is one of the plantar flexors in the posterior compartment of the leg, along with the gastrocnemius and soleus. The plantaris is considered an unimportant muscle and mainly acts with the gastrocnemius.[1]

Structure[edit]

It arises from the inferior part of the lateral supracondylar ridge of the femur at a position slightly superior to the origin of the lateral head of gastrocnemius.

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.

Innervation[edit]

It is innervated by the tibial nerve (S1,S2) .

Variation[edit]

Also, it may arise from the oblique popliteal ligament.

Function[edit]

Plantaris acts to weakly:

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.[2]

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 new medical students (and thus called the "freshman nerve"), the muscle was useful to other primates for grasping with their feet.

Clinical significance[edit]

The plantaris is mainly used by surgeons for tendon grafts needed in other areas of the body. Although the plantaris does have little importance, there are injuries that can occur. It can be damaged in an Achilles tendon rupture. Tennis leg is a commonly known injury. It is a result of eccentric loading placed on the ankle while the knee is extended, and occurs while running or jumping. It may cause a direct trauma to the calf area. Pain and swelling are common in the injury. It is sometimes removed to treat its inflammation.[3]

Additional images[edit]

References[edit]

  1. ^ DR. K. Musculoskeletal cases website: Plantaris tendon tear[dead link]
  2. ^ Moore, Keith L; & Dalley Arthur R (2008). Clinically Oriented Anatomy (6th ed.). Lippincott Williams and Wilkins. ISBN 978-1-60547-652-0
  3. ^ http://news.bbc.co.uk/sport2/hi/football/14801756.stm

External links[edit]