Popliteus Muscle
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 the 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 shape muscle.
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 an assistant knee flexor muscle
- In open chain knee flexion movement, it rotates tibia medially
- In close chain position knee movement it laterally rotates femur in the very beginning of knee flexion, as in close pack position knee is locked for stability by medial rotation of femur and popliteus laterally rotates the Femur in beginning of movement its called as 'key'of lock
- It drags lateral meniscus posterior during knee flexion so prevents it from injury.
- Knee stabilitiy,The popliteus tendon is frequently found to be connected to the lateral capsule. This gives the muscle a possible role in postero-lateral stability of the knee[2][3].Krudwig et al [4]consider the Popliteus as an important structure resisting excessive external tibial rotation and maintaining the neutral tibial rotation, even if all other postero-lateral ligaments were cut.
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[5].
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[6]. 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.
Travell & Simons (1992) also note that the popliteus prevents forward displacement of the femur on the tibial plateau. ‘Its contraction specifically prevents the lateral femoral condyle from rotating forward off the lateral tibial plateau.’ Their described trigger point referral pattern for popliteus is primarily into the back of the knee.
More about popliteus muscle pathology on physiopedia Popliteus strain,Popliteus Tendinitis
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[7].
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)[8] 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.[9]
Only a portion of the popliteus can be safely palpated due to the neurovascular structures that overlie it. The attachment on the tibial shaft can usually be reached as well as the tendon at the femoral condyle.
The popliteus together with the posteror cruciate ligament slows down forward shift of the femur over the flexed tibia while stance phase, particularly while running downhill. The popliteal tendon can be associated in the same manner with a tenosynovitis, tendinopathy, rupture, or avulsion. Tendinopathy as well as tenosynovitis may result from both hyperpronation as well as downhill running, particularly on banked surfaces
Treatment[edit | edit source]
The treatment for popliteus muscle pathology same as per any soft tissue injury and muscle injury or tendinitis. RICE Therapy OR PRICE Therapy(protection,rest,elevation,compression,elevation ,and other anti-inflammatory drugs are given.
Physiotherapy treatment is on the line with other soft tissues and muscle injuries, mobility exercises, strengthening exercises, eccentric training and many more rehab protocols depending upon pathology, associated injuries and patients condition.
spray-and-stretch techniques, as described by Travell & Simons (1992), if trigger point of pain present may be effective[11].
References[edit | edit source]
- ↑ Standring S, editor. Gray's anatomy e-book: the anatomical basis of clinical practice. Elsevier Health Sciences; 2015 Aug 7.
- ↑ De Maeseneer, M. Shahabpour, K. Vanderdood, 2001, Posterolateral supporting structures of the knee, Eur Radiol 11:2170-2177
- ↑ Kim, In Hyuk Chung, Woo Kyung Yoo, 1997, Anatomy and Magnetic Resonance imaging of the Posterolateral Structures of the Knee, Clinical Anatomy 10: 397-404
- ↑ Krudwig W K, Witzel U, Ullrich K 2002 Posterolateral aspect and stability of the knee joint Knee Surg., Sports Traumatol, Arthrose, 10:91-95.
- ↑ JONATHAN FITZGORDON.Knee Stuff: The Popliteus Musclehttps://corewalking.com/knee-stuff-popliteus-muscle/ (accessed on 18 June 2018)
- ↑ 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.
- ↑ Kenhub.Popliteus Muscle.https://www.kenhub.com/en/library/anatomy/popliteus-muscle (accessed on 18 June 2018)
- ↑ 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.
- ↑ Earthslab.Popliteus fossa. https://www.earthslab.com/anatomy/popliteal-fossa/ (accessed on 18 June 2018)
- ↑ Travell JG, Simons DG. Myofascial pain and dysfunction, vols 1 and 2. Baltimore: Williams and Wilkins. 1992.
