Popliteus Muscle
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Description[edit | edit source]
Popliteus [pop-lit-ee-uh s, pop-li-tee-] is the muscle of the leg.Its deepest muscle of the knee joint which forms floor of the popliteus fossa. It is the only muscle in the posterior (back) compartment of the lower leg that acts just on the knee and not on the ankle.Its a thin,flat ,triangular shapemuscle.
Origin[edit | edit source]
The lateral condyle of the femur and the posterior horn of the lateral meniscus,From there it runs mediocaudally towards the tibia..Popliteus courses diagonally across the posterior upper tibia and a portion of the joint capsule to lie as the deepest muscle of the posterior knee region. Its tendon pierces the joint capsule but does not enter the synovium and is crossed by the arcuate ligament, the lateral collateral ligament and the tendon of biceps femoris. The popliteus bursa, which is usually an extension of the synovial membrane, separates it from the lateral femoral condyle. An additional head of popliteus may arise from a sesamoid in gastrocnemius' lateral head and very rarely two other muscles may be present.1
Insertion[edit | edit source]
It is inserted just proximal to the soleal line but below the tibial condyles
Nerve[edit | edit source]
The popliteus muscle is supplied via fibers of the tibial nerve(L4-S1), direct through a section of the nerve towards the tibialis posterior muscle and also in some cases from a section via the main nerve towards the knee joint. These nerve fibers emerge through the fourth as well as fifth lumbar along with the first sacral spinal nerves to the popliteus muscle.
Artery[edit | edit source]
Muscular branches of Popliteal Artery supplies the popliteus muscle
Function[edit | edit source]
The popliteus muscle is a assistant knee flexor muscle
1.In open chain movement it rotates tibia medially
2.In close chain position it laterally rotates femur in very beginning of knee flexion,as in close pack position knee is locked for stability by medial rotation of femur and popliteus laterally rotates femur in beginning of movement its called as 'key'of lock
3.It drags lateral meniscus posterior during knee flexion so prevents it from injury.
Clinical relevance[edit | edit source]
Poor movement patterns and posture often weigh heavily on the popliteus muscle leaving it prone too weakness and injury. Any inury to the knee will likely involve the popliteus muscle..
If the hamstrings towards the outer thigh are stronger than the inner hamstrings, the popliteus muscle will be weaker. Excessive pronation or collapse of the inner foot when walking or running will stress the popliteus in the opposite direction[1].
Assessment[edit | edit source]
The popliteus muscle may be injured in the scope of a rupture of the anterior cruciate ligament or damages involving the lateral meniscus. In contrast, an isolated damage of the muscle is rather rare.
Clinically the affected patients present with an unnatural outward rotation of the tibia when bending the knee. Additionally other general symptoms often occur such as muscle swelling, edema or bleeding[2].
Popliteus injury may be suspected with tenderness over the proximal aspect of the popliteus tendon with the patient in the prone position. There may be pain with resisted external rotation of the lower leg with the hip and knee flexed to 90 degrees (positive Garrick test)[3] A “shoe removal maneuver” in which the athlete internally rotates the injured lower leg to push off the contralateral shoe at the heel may also produce pain. Tenderness over the posterolateral knee may raise suspicion of a strain of the biceps femoris tendon or of injury to the lateral meniscus, which should be considered in the differential diagnosis. MRI may show edema within the muscle at the musculotendinous junction. An isolated acute rupture of the popliteus tendon was found in 2 of 2412 knee MRI studies.[4]
Stäubli and Birrer found that the popliteus muscle’s tendon gradually increases when the knee extends. They suggest that the PM and its intact fasciculii play an important role in restraining hyperextension[5]. Davis et al using electromyography (EMG), could see the same happening in some patients during gait. They also found an increase in EMG during downhill walking.
Treatment[edit | edit source]
Resources[edit | edit source]
- ↑ https://corewalking.com/knee-stuff-popliteus-muscle/
- ↑ [1]
- ↑ Covey DC. Injuries of the posterolateral corner of the knee. JBJS. 2001 Jan 1;83(1):106-18.
- ↑ Lubowitz JH, Bernardini BJ, Reid III JB. Current concepts review: comprehensive physical examination for instability of the knee. The American journal of sports medicine. 2008 Mar;36(3):577-94.
- ↑ Stäubli H-U, Birrer S 1990 The Popliteus Tendon and its fascicles at the Popliteal hiatus The Journal of Arthroscopic and Related Surgery 6(3): 209-220.
