Popliteus muscle
| Popliteus muscle | |
|---|---|
 | |
| Deep layer of muscles on the back of the leg (popliteus visible at center top) | |
| Latin | Musculus popliteus |
| Gray's | p.484 |
| Origin | Posterior-lateral surface of femur below the lateral condyle |
| Insertion | Medial surface of the proximal tibia below the medial condyle |
| Artery | Popliteal artery |
| Nerve | Tibial nerve |
| Actions | Lateral rotation of femur and flexion of knee |
The popliteus muscle in the leg is used for unlocking the knees during walking/standing by laterally rotating the femur on the tibia (or medially rotating the tibia) during a closed chain movement (such as one with the foot in contact with the ground).
Origin and insertion
It originates from lateral surface of lateral epicondyle on the femur. The muscle insertion is on the posterior surface of the body of tibia above the soleal line.
Innervation
Nerve supply is via the tibial nerve from spinal roots L5 and S1.
Action
The popliteus assists in flexing the leg upon the thigh; when the leg is flexed, it will rotate the tibia inward.
It is especially called into action at the beginning of the act of bending the knee, in as much as it produces the slight inward rotation of the tibia, which is essential in the early stage of this movement.
When the knee is in full extension; the femur slightly medially rotates on the tibia to lock the knee joint in place. Popliteus is often referred to as the "Key" to unlocking the knee since it begins knee flexion by laterally rotating the femur on the tibia.
Popliteus is also attached to the lateral meniscus in the knee; and draws it posteriorly during knee flexion to prevent crushing the meniscus between the tibia and femur as the knee flexes.
Variations
Additional head from the sesamoid bone in the lateral (outer) head of the gastrocnemius muscle.
Rarely an additional inconstant muscle; the popliteus minor is seen. It originates from the femur on the inner side of the plantaris muscle and inserts into the posterior ligament of the knee-joint.
Peroneotibialis, 14% of population. Origin is inner side of the head of the fibula, insertion into the upper end of the oblique line of the tibia, it lies beneath the popliteus.[1]
Trigger points
A popliteus shortened by trigger points can cause pain near its tendinous origin at the lateral knee.
Additional images
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Right femur. Posterior surface.
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Bones of the right leg. Posterior surface.
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Capsule of right knee-joint (distended). Posterior aspect.
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The popliteal, posterior tibial, and peroneal arteries.
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Muscles of the leg seen from behind.
See also
- Posterolateral Knee
References
This article incorporates text from a public domain edition of Gray's Anatomy.
External links
- LUC pop
- 93978702 at GPnotebook
- 15:st-0413 at the SUNY Downstate Medical Center
- popliteus+%28muscle%29 at eMedicine Dictionary
- PTCentral
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