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== Description  ==
== Description  ==
[[File:Popliteus.png.png|thumb]]The Popliteus is a small, thin, flat, triangular shaped muscle of the lower leg. It is a deep muscle of the knee joint which forms the floor of the popliteus fossa. It also forms the lateral musculature of the knee joint, along with the [[Iliotibial Tract|iliotibial band]].It is the only muscle in the posterior compartment of the lower leg (which also includes [[Tibialis Posterior|tibialis posterior]], [[flexor digitorum longus]], and [[flexor hallucis longus]]) which is mono-articular (for on the knee joint) and does not influence the ankle joint.  
[[File:Gray439-Musculus popliteus.png|alt=https://en.wikipedia.org/wiki/Popliteus_muscle#/media/File:Gray439-Musculus_popliteus.png|thumb|504x504px|[https://en.wikipedia.org/wiki/Popliteus_muscle#/media/File:Gray439-Musculus_popliteus.png Popliteus]]]
The Popliteus is a small, thin, flat, triangular shaped musclotendinous complex of the lower leg with the popliteus muscle and the popliteofibular ligament and constitutes a part of the posterolateral corner of the knee.. It is a deep muscle of the knee joint, forming the floor of the [[Popliteal Fossa|popliteus fossa]]. It also makes up the lateral musculature of the knee joint, along with the [[Iliotibial Tract|iliotibial band]]. It is the only muscle in the posterior compartment of the lower leg (which also includes [[Tibialis Posterior|tibialis posterior]], [[flexor digitorum longus]], and [[flexor hallucis longus]]) which is mono-articular and does not influence the ankle joint.  


It is one of the main posterolateral stabilisers of the knee joint, causing rotation of the knee medially and laterally,<ref>Abulhasan, J.F.; Grey, M.J. [https://www.mdpi.com/2411-5142/2/4/34/htm Anatomy and Physiology of Knee Stability]. ''J. Funct. Morphol. Kinesiol.'' 2017, ''2'', 34.</ref> thereby being involved in both the closed chain phase and open chain phase of the [[Gait Cycle|gait cycle]].<ref name=":2">Hyland S, Varacallo M. [https://www.ncbi.nlm.nih.gov/books/NBK526084/ Anatomy, Bony Pelvis and Lower Limb, Popliteus Muscle.] [Updated 2020 Aug 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-.</ref>  
It is one of the main posterolateral stabilisers of the knee joint, causing both medial and lateral rotation of the knee, <ref>Abulhasan, J.F.; Grey, M.J. [https://www.mdpi.com/2411-5142/2/4/34/htm Anatomy and Physiology of Knee Stability]. ''J. Funct. Morphol. Kinesiol.'' 2017, ''2'', 34.</ref> thereby being involved in both the closed chain phase and open-chain phase of the [[Gait Cycle|gait cycle]].<ref name=":2">Hyland S, Varacallo M. [https://www.ncbi.nlm.nih.gov/books/NBK526084/ Anatomy, Bony Pelvis and Lower Limb, Popliteus Muscle.] [Updated 2020 Aug 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-.</ref> It also works as a smaller stabilizer in regard to internal rotation anterior translation and varus force.
=== Origin ===
=== Origin ===
The lateral condyle of the femur and the posterior horn of the lateral meniscus, From there it runs inferiorly and mediolaterally  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.<ref>Standring S, editor. Gray's anatomy e-book: the anatomical basis of clinical practice. Elsevier Health Sciences; 2015 Aug 7.</ref>
The muscle fibres originate from the lateral condyle of the femur and the posterior horn of the lateral meniscus, via a strong tendon called the popliteus tendon. Cadaveric dissections have also shown fibres originating from the styloid portion of the fibular head, which then runs obliquely blending with the main muscular structure.<ref name=":2" />


From there it runs inferiorly and mediolaterally towards the [[Tibia]]. It 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. The popliteal tendon pierces the joint capsule but does not enter the synovium. The popliteus tendon passes beneath the lateral collateral ligament (LCL) and the tendon of the biceps femoris.
The popliteal bursa, which is usually an extension of the synovial membrane, separates it from the lateral femoral condyle. Although the popliteus muscle has extra-articular areas, it is a capsular structure separating the lateral meniscus of the knee from the lateral collateral ligament. An additional head of popliteus may arise from the sesamoid bone in the lateral head of the gastrocnemius muscle. Rarely an additional inconstant muscle called the popliteus minor is seen which arises from the femur on the inner side of the plantaris muscle and inserts into the posterior ligament of the knee joint.
The popliteus muscle is intra-capsular but extra-articular and extra-synovial.
=== Insertion  ===
=== Insertion  ===
It is inserted on the tibia just proximal to the soleal line but below the tibial condyles
It inserts on the tibia just proximal to the soleal line but below the tibial condyles.


=== Nerve ===
=== Nerve ===
The popliteus muscle is supplied via fibres 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 fibres emerge through the fourth as well as fifth lumbar along with the first sacral spinal nerves to the popliteus muscle.
The popliteus muscle is supplied by the tibial nerve, from spinal nerve roots L4 through S1, with approximately 2 to 3 parallel tibial nerve branches. The entry point of the nerve is the lateral distal margin of the muscle, which is found inferior to the fibular head, and then splits into anterior, medial, and lateral distributions throughout the muscle.


=== Artery ===
=== Artery ===
Muscular branches of '''Popliteal Artery''' supplies the popliteus muscle
The popliteus muscle is supplied by 2 arteries -
* the medial inferior genicular branch of the popliteal artery
* the muscular branch of the posterior tibial artery.
 


== Function ==
== Function ==
The popliteus muscle is an assistant knee flexor muscle
The popliteus muscle assists in knee flexion and its function is decided according to the position of the lower extremity, i.e. weight-bearing or non weight-bearing, as it is a primary internal rotator of the tibia in a non weight-bearing position.<ref name=":2" />
# In '''open chain''' knee flexion movement, it '''rotates tibia medially'''
# In open chain kinematics, 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
# In close chain kinematics, it laterally rotates femur in the initial phase of knee flexion.
# It '''drags lateral meniscus posterio'''r during knee flexion so prevents it from injury.
# With extension during weight-bearing, 'locking' of the knee occurs. In this state, the femur medially rotates on the tibia, allowing for full extension without muscular expenditure. To 'unlock' the knee, the popliteus muscle needs to contract, causing flexion and lateral rotation of the femur on the tibia, thereby giving the muscle the term - 'key' to the locked knee.
# '''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<ref>De Maeseneer, M. Shahabpour, K. Vanderdood, 2001, Posterolateral supporting structures of the knee, Eur Radiol 11:2170-2177</ref><ref>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</ref>. Krudwig et al <ref>Krudwig W K, Witzel U, Ullrich K 2002 Posterolateral aspect and stability of the knee joint Knee Surg., Sports Traumatol, Arthrose, 10:91-95.</ref>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.
# During knee flexion, the popliteus muscle retracts the lateral meniscus posteriorly to avoid being entrapped between the femur and tibia.<ref name=":2" />
# In knee stability - as 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<ref>De Maeseneer, M. Shahabpour, K. Vanderdood, 2001, Posterolateral supporting structures of the knee, Eur Radiol 11:2170-2177</ref><ref>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</ref>. Krudwig et al <ref>Krudwig W K, Witzel U, Ullrich K 2002 Posterolateral aspect and stability of the knee joint Knee Surg., Sports Traumatol, Arthrose, 10:91-95.</ref>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 severed.  


==Video==
== Clinical relevance  ==
It is commonly involved in the posterolateral (PCL) corner injuries of the knee, which occur secondary to -
# varus force applied to a flexed knee.
# a direct blow to the knee (from medial to lateral).
# varus/hyperextension ( both from contact and non-contact injuries)
# dislocation of the knee.
Whatever the mechanism of injury to the PCL corner (from the above), urgent evaluation of the patient's neurovascular status of the limb is performed. In the case of knee dislocation, vascular status is assessed followed by closed reduction of the knee joint which is then again followed by assessing the vascular status.


{{#ev:youtube|X7xbuAN2XDk}}
Further to trauma, poor movement patterns and posture can often weigh heavily on the popliteus muscle leaving it prone to weakness and injury. Iatrogenic injury to this muscle is common, which can lead to poor functional prognosis and hence becomes vital to be addressed - especially following knee reconstruction surgery. Anatomical smaller knees also need extra attention as the risk of popliteal injury is increased. <ref name=":2" />


== Clinical relevance  ==
Popliteal tendinopathy can also occur as posterolateral knee pain. However, it can be difficult to single it out due to other more common knee pain etiologies in the vicinity. As this muscle inhibits excessive tibial rotation along with preventing significant anterior translation of the knee, it can be pathologically overcome secondary to excessive sprinting or running downhill and hence such activities should be avoided or modified to run on flat surfaces like a treadmill.  
It is commonly involved in the posterolateral corner injuries of the knee, which occur secondary to a varus force or direct blow to the knee (from medial to lateral).<ref name=":2" />


Further to trauma, poor movement patterns and posture can often weigh heavily on the popliteus muscle leaving it prone too weakness and injury. Iatrogenic injury to this muscle is common, which can lead to poor functional prognosis and hence becomes vital to be addressed esp following knee reconstruction surgery. Anatomical smaller knees also need extra attention as the risk of popliteal injury is increased. <ref name=":2" />
If the lateral hamstrings are stronger than the inner (medial)  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<ref>JONATHAN FITZGORDON.Knee Stuff: The Popliteus Muscle<nowiki/>https://corewalking.com/knee-stuff-popliteus-muscle/ (accessed on 18 June 2018)</ref>.


Any injury to the knee will likely involve the popliteus muscle.
Different EMG studies have shown that popliteus muscle activity increases with knee extension and downhill walking, thereby consolidating its role in the control of hyperextension of the knee joint<ref>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.</ref>.  


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<ref>JONATHAN FITZGORDON.Knee Stuff: The Popliteus Muscle<nowiki/>https://corewalking.com/knee-stuff-popliteus-muscle/ (accessed on 18 June 2018)</ref>.
The referred pain pattern in case of trigger point of popliteus muscle is back of knee<ref name=":0">Travell JG, Simons DG. Myofascial pain and dysfunction, vols 1 and 2. Baltimore: Williams and Wilkins. 1992.</ref>.


Different EMG studied showed that popliteus muscle activity increases with knee extension and downhill walking so it is playing role to control hyperextension of knee<ref>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.</ref>. The referred pain pattern in case of trigger point of popliteus muscle is back of knee<ref name=":0">Travell JG, Simons DG. Myofascial pain and dysfunction, vols 1 and 2. Baltimore: Williams and Wilkins. 1992.</ref>.
More about popliteus muscle pathology on Physiopedia, read: [[Popliteus strain]],[[Popliteus Tendinitis]]
 
More about popliteus muscle pathology on physiopedia [[Popliteus strain]],[[Popliteus Tendinitis]]


== Assessment  ==
== Assessment  ==
Due to deep location isolated injury to popliteus muscle is rare but it may be associated with other knee injuries such as ACL injury, meniscus injuries.
Due to its deep location, isolated injuries to the popliteus muscle are rare but can be associated with other knee injuries such as ACL injury, meniscus injuries.


There are general symptoms of muscle injury like swelling, tenderness, oedema, bleeding, patient keeps leg (tibia) in lateral rotation during knee flexion.<ref>Kenhub[https://www.kenhub.com/en/library/anatomy/popliteus-muscle .]Popliteus Muscle[https://www.kenhub.com/en/library/anatomy/popliteus-muscle .https://www.kenhub.com/en/library/anatomy/popliteus-muscle] (accessed on 18 June 2018)</ref>.
There are general symptoms of muscle injury which include swelling, tenderness, oedema, bleeding, patient keeping the leg (tibia) in lateral rotation during knee flexion.<ref>Kenhub[https://www.kenhub.com/en/library/anatomy/popliteus-muscle .]Popliteus Muscle[https://www.kenhub.com/en/library/anatomy/popliteus-muscle .https://www.kenhub.com/en/library/anatomy/popliteus-muscle] (accessed on 18 June 2018)</ref>.


Following should be checked to rule out popliteus muscle injury.
Following should be checked to rule out popliteus muscle injury.
# '''Tenderness''';-.As many neurovascular structure lie over it only terminal portions of popliteus muscle can be palpated.Tenderness over proximal popliteus tendon checked in prone lying position while tenderness over posterolateral knee may be sign of biceps femoris tendon strain and lateral meniscus injury.
# '''Tenderness -''' As many neurovascular structures lie over it, only terminal portions of popliteus muscle can be palpated. Proximal tendon tenderness is checked in a prone lying position, whilst tenderness over the posterolateral knee may be a sign of biceps femoris tendon strain and/or lateral meniscus injury.
# '''Garrick test'''<ref name=":1">Covey DC. Injuries of the posterolateral corner of the knee. JBJS. 2001 Jan 1;83(1):106-18.</ref> In high sitting position where hip and knee both flexed to 90 degrees resisted external rotation of lower leg is checked. Pain during manoeuvre considered as positive test
# '''Garrick test'''<ref name=":1">Covey DC. Injuries of the posterolateral corner of the knee. JBJS. 2001 Jan 1;83(1):106-18.</ref>- Pt is in a high sitting position with hip and knee flexed at 90 degrees. Resistance to external rotation of the lower leg is applied. Pain during this manoeuvre is considered to be a positive test
# '''Shoe removal manoeuvre'''<ref name=":1" />Patient tries to remove contralateral shoe by internally rotating affected leg to reach heel of another leg. Pain during manoeuvre indicates injury to popliteus muscle.
# '''Shoe removal manoeuvre'''<ref name=":1" />Patient tries to remove contralateral shoe by internally rotating the affected leg to reach the heel of the opposite leg. Pain during this manoeuvre indicates injury to popliteus muscle.
As said earlier isolated injury to popliteus muscle is rare ,nn isolated acute rupture of the popliteus tendon was found in 2 of 2412 knee MRI studies.<ref>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.</ref> 
As said earlier, isolated injuries to popliteus muscle are rare and only 2 out of 2412 knee MRI studies<ref>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.</ref> showed isolated acute rupture of the popliteus tendon. 


The popliteus muscle along with PCL (posterior cruciate ligament ) of knee stabilises femur over fixed tibia in stance phase specially when extra stability is needed like running downhill.So running downhill specially on banked surface and hyperpronation leads to popliteus muscle injury like tenosynivitis, tendinopathy, ruptute, strain.<ref>Earthslab.Popliteus fossa. https://www.earthslab.com/anatomy/popliteal-fossa/ (accessed on 18 June 2018)</ref>
The popliteus muscle, along with PCL (posterior cruciate ligament ), stabilises the femur over fixed tibia in the stance phase especially when extra stability is needed for activities like running downhill. Hence running downhill especially on banked surface with hyperpronation can lead to popliteus muscle injury like tenosynovitis, tendinopathy, rupture, strain.<ref>Earthslab.Popliteus fossa. https://www.earthslab.com/anatomy/popliteal-fossa/ (accessed on 18 June 2018)</ref>
 
{{#ev:youtube|zO95xFvEVG4}}<ref>DOOLEY NOTED: Popliteus Muscle Location for Knee Pain. Available from: http://www.youtube.com/watch?v=zO95xFvEVG4</ref>  


== Treatment  ==
== Treatment  ==
The treatment for popliteus muscle pathology same as per any soft tissue injury and muscle injury or [[tendinopathy]]. [[POLICE Principle|RICE Therapy]] OR [[POLICE Principle|PRICE]] Therapy (protection, rest, elevation, compression, elevation, and other anti-inflammatory drugs are given.
The treatment for popliteus muscle pathology is the same as per any soft tissue injury and muscle injury or [[tendinopathy]]. [[POLICE Principle|RICE Therapy]] or [[POLICE Principle|PRICE]] Therapy (protection, rest, elevation, compression, elevation, and other anti-inflammatory drugs are given.
 
Physiotherapy treatment is in line with other soft tissue and muscle injuries which includes mobility exercises, strengthening exercises, eccentric training and many more rehab protocols depending upon pathology, associated injuries and patient condition.
 
{{#ev:youtube|Dcw9xlv25Ww}}<ref>How to Reset the Popliteus. Available from: http://www.youtube.com/watch?v=Dcw9xlv25Ww</ref>
 
== Exercise ==
 
# Sit with foot dorsiflexed such that heel is touching the ground. Perform interal rotation of the foot. Can be done with or without resistance band with band tied to forefoot.
# Popliteal muscle release - Long sitting with a lacrosse ball behind flexed knee and search for tender areas. Slowly add pressure. If tender or numb, move to slightly different area, add movement by internal and external rotation of lower leg.
# Isometrically perform internal rotation with forefoot in sitting on a bar or table.
# Open-chain full ROM of knee with resistance band tied on forefoot laterally resisting internal rotation.
# Close chain proprioception exercise on bosu ball with affected leg fixed on bosu ball and perform cross lunge.
# Single leg forward jumps with knee slightly flexed.


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.
== Resources ==
This 2 minute video is a good summary of the popliteus muscle.<ref>Popliteus Muscle - Origin, Insertion, Function & Innervation - Human Anatomy | Kenhub. Available from: http://www.youtube.com/watch?v=X7xbuAN2XDk</ref> {{#ev:youtube|X7xbuAN2XDk}}


== Related Pages ==
== Related Pages ==

Latest revision as of 18:39, 17 March 2023

Original Editors - Hardik Bhatt as part of the Vrije Universiteit Brussel Evidence-based Practice Project

Top Contributors - Hardik Bhatt, Saumya Srivastava, Kim Jackson, Mariam Hashem, Rachael Lowe, Joao Costa, Yvonne Yap, Lucinda hampton, Shreya Pavaskar, Admin and Oyemi Sillo

Description[edit | edit source]

https://en.wikipedia.org/wiki/Popliteus_muscle#/media/File:Gray439-Musculus_popliteus.png
Popliteus

The Popliteus is a small, thin, flat, triangular shaped musclotendinous complex of the lower leg with the popliteus muscle and the popliteofibular ligament and constitutes a part of the posterolateral corner of the knee.. It is a deep muscle of the knee joint, forming the floor of the popliteus fossa. It also makes up the lateral musculature of the knee joint, along with the iliotibial band. It is the only muscle in the posterior compartment of the lower leg (which also includes tibialis posterior, flexor digitorum longus, and flexor hallucis longus) which is mono-articular and does not influence the ankle joint.

It is one of the main posterolateral stabilisers of the knee joint, causing both medial and lateral rotation of the knee, [1] thereby being involved in both the closed chain phase and open-chain phase of the gait cycle.[2] It also works as a smaller stabilizer in regard to internal rotation anterior translation and varus force.

Origin[edit | edit source]

The muscle fibres originate from the lateral condyle of the femur and the posterior horn of the lateral meniscus, via a strong tendon called the popliteus tendon. Cadaveric dissections have also shown fibres originating from the styloid portion of the fibular head, which then runs obliquely blending with the main muscular structure.[2]

From there it runs inferiorly and mediolaterally towards the Tibia. It 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. The popliteal tendon pierces the joint capsule but does not enter the synovium. The popliteus tendon passes beneath the lateral collateral ligament (LCL) and the tendon of the biceps femoris.

The popliteal bursa, which is usually an extension of the synovial membrane, separates it from the lateral femoral condyle. Although the popliteus muscle has extra-articular areas, it is a capsular structure separating the lateral meniscus of the knee from the lateral collateral ligament. An additional head of popliteus may arise from the sesamoid bone in the lateral head of the gastrocnemius muscle. Rarely an additional inconstant muscle called the popliteus minor is seen which arises from the femur on the inner side of the plantaris muscle and inserts into the posterior ligament of the knee joint.

The popliteus muscle is intra-capsular but extra-articular and extra-synovial.

Insertion[edit | edit source]

It inserts on the tibia just proximal to the soleal line but below the tibial condyles.

Nerve[edit | edit source]

The popliteus muscle is supplied by the tibial nerve, from spinal nerve roots L4 through S1, with approximately 2 to 3 parallel tibial nerve branches. The entry point of the nerve is the lateral distal margin of the muscle, which is found inferior to the fibular head, and then splits into anterior, medial, and lateral distributions throughout the muscle.

Artery[edit | edit source]

The popliteus muscle is supplied by 2 arteries -

  • the medial inferior genicular branch of the popliteal artery
  • the muscular branch of the posterior tibial artery.


Function[edit | edit source]

The popliteus muscle assists in knee flexion and its function is decided according to the position of the lower extremity, i.e. weight-bearing or non weight-bearing, as it is a primary internal rotator of the tibia in a non weight-bearing position.[2]

  1. In open chain kinematics, it rotates tibia medially
  2. In close chain kinematics, it laterally rotates femur in the initial phase of knee flexion.
  3. With extension during weight-bearing, 'locking' of the knee occurs. In this state, the femur medially rotates on the tibia, allowing for full extension without muscular expenditure. To 'unlock' the knee, the popliteus muscle needs to contract, causing flexion and lateral rotation of the femur on the tibia, thereby giving the muscle the term - 'key' to the locked knee.
  4. During knee flexion, the popliteus muscle retracts the lateral meniscus posteriorly to avoid being entrapped between the femur and tibia.[2]
  5. In knee stability - as 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[3][4]. Krudwig et al [5]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 severed.

Clinical relevance[edit | edit source]

It is commonly involved in the posterolateral (PCL) corner injuries of the knee, which occur secondary to -

  1. varus force applied to a flexed knee.
  2. a direct blow to the knee (from medial to lateral).
  3. varus/hyperextension ( both from contact and non-contact injuries)
  4. dislocation of the knee.

Whatever the mechanism of injury to the PCL corner (from the above), urgent evaluation of the patient's neurovascular status of the limb is performed. In the case of knee dislocation, vascular status is assessed followed by closed reduction of the knee joint which is then again followed by assessing the vascular status.

Further to trauma, poor movement patterns and posture can often weigh heavily on the popliteus muscle leaving it prone to weakness and injury. Iatrogenic injury to this muscle is common, which can lead to poor functional prognosis and hence becomes vital to be addressed - especially following knee reconstruction surgery. Anatomical smaller knees also need extra attention as the risk of popliteal injury is increased. [2]

Popliteal tendinopathy can also occur as posterolateral knee pain. However, it can be difficult to single it out due to other more common knee pain etiologies in the vicinity. As this muscle inhibits excessive tibial rotation along with preventing significant anterior translation of the knee, it can be pathologically overcome secondary to excessive sprinting or running downhill and hence such activities should be avoided or modified to run on flat surfaces like a treadmill.

If the lateral hamstrings are stronger than the inner (medial) 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[6].

Different EMG studies have shown that popliteus muscle activity increases with knee extension and downhill walking, thereby consolidating its role in the control of hyperextension of the knee joint[7].

The referred pain pattern in case of trigger point of popliteus muscle is back of knee[8].

More about popliteus muscle pathology on Physiopedia, read: Popliteus strain,Popliteus Tendinitis

Assessment[edit | edit source]

Due to its deep location, isolated injuries to the popliteus muscle are rare but can be associated with other knee injuries such as ACL injury, meniscus injuries.

There are general symptoms of muscle injury which include swelling, tenderness, oedema, bleeding, patient keeping the leg (tibia) in lateral rotation during knee flexion.[9].

Following should be checked to rule out popliteus muscle injury.

  1. Tenderness - As many neurovascular structures lie over it, only terminal portions of popliteus muscle can be palpated. Proximal tendon tenderness is checked in a prone lying position, whilst tenderness over the posterolateral knee may be a sign of biceps femoris tendon strain and/or lateral meniscus injury.
  2. Garrick test[10]- Pt is in a high sitting position with hip and knee flexed at 90 degrees. Resistance to external rotation of the lower leg is applied. Pain during this manoeuvre is considered to be a positive test
  3. Shoe removal manoeuvre[10]Patient tries to remove contralateral shoe by internally rotating the affected leg to reach the heel of the opposite leg. Pain during this manoeuvre indicates injury to popliteus muscle.

As said earlier, isolated injuries to popliteus muscle are rare and only 2 out of 2412 knee MRI studies[11] showed isolated acute rupture of the popliteus tendon. 

The popliteus muscle, along with PCL (posterior cruciate ligament ), stabilises the femur over fixed tibia in the stance phase especially when extra stability is needed for activities like running downhill. Hence running downhill especially on banked surface with hyperpronation can lead to popliteus muscle injury like tenosynovitis, tendinopathy, rupture, strain.[12]

[13]

Treatment[edit | edit source]

The treatment for popliteus muscle pathology is the same as per any soft tissue injury and muscle injury or tendinopathy. RICE Therapy or PRICE Therapy (protection, rest, elevation, compression, elevation, and other anti-inflammatory drugs are given.

Physiotherapy treatment is in line with other soft tissue and muscle injuries which includes mobility exercises, strengthening exercises, eccentric training and many more rehab protocols depending upon pathology, associated injuries and patient condition.

[14]

Exercise[edit | edit source]

  1. Sit with foot dorsiflexed such that heel is touching the ground. Perform interal rotation of the foot. Can be done with or without resistance band with band tied to forefoot.
  2. Popliteal muscle release - Long sitting with a lacrosse ball behind flexed knee and search for tender areas. Slowly add pressure. If tender or numb, move to slightly different area, add movement by internal and external rotation of lower leg.
  3. Isometrically perform internal rotation with forefoot in sitting on a bar or table.
  4. Open-chain full ROM of knee with resistance band tied on forefoot laterally resisting internal rotation.
  5. Close chain proprioception exercise on bosu ball with affected leg fixed on bosu ball and perform cross lunge.
  6. Single leg forward jumps with knee slightly flexed.

Resources[edit | edit source]

This 2 minute video is a good summary of the popliteus muscle.[15]

Related Pages[edit | edit source]

Popliteus Strain

Popliteus Tendinopathy

References[edit | edit source]

  1. ↑ Abulhasan, J.F.; Grey, M.J. Anatomy and Physiology of Knee Stability. J. Funct. Morphol. Kinesiol. 2017, 2, 34.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Hyland S, Varacallo M. Anatomy, Bony Pelvis and Lower Limb, Popliteus Muscle. [Updated 2020 Aug 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-.
  3. ↑ De Maeseneer, M. Shahabpour, K. Vanderdood, 2001, Posterolateral supporting structures of the knee, Eur Radiol 11:2170-2177
  4. ↑ 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
  5. ↑ Krudwig W K, Witzel U, Ullrich K 2002 Posterolateral aspect and stability of the knee joint Knee Surg., Sports Traumatol, Arthrose, 10:91-95.
  6. ↑ JONATHAN FITZGORDON.Knee Stuff: The Popliteus Musclehttps://corewalking.com/knee-stuff-popliteus-muscle/ (accessed on 18 June 2018)
  7. ↑ 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.
  8. ↑ Travell JG, Simons DG. Myofascial pain and dysfunction, vols 1 and 2. Baltimore: Williams and Wilkins. 1992.
  9. ↑ Kenhub.Popliteus Muscle.https://www.kenhub.com/en/library/anatomy/popliteus-muscle (accessed on 18 June 2018)
  10. ↑ 10.0 10.1 Covey DC. Injuries of the posterolateral corner of the knee. JBJS. 2001 Jan 1;83(1):106-18.
  11. ↑ 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.
  12. ↑ Earthslab.Popliteus fossa. https://www.earthslab.com/anatomy/popliteal-fossa/ (accessed on 18 June 2018)
  13. ↑ DOOLEY NOTED: Popliteus Muscle Location for Knee Pain. Available from: http://www.youtube.com/watch?v=zO95xFvEVG4
  14. ↑ How to Reset the Popliteus. Available from: http://www.youtube.com/watch?v=Dcw9xlv25Ww
  15. ↑ Popliteus Muscle - Origin, Insertion, Function & Innervation - Human Anatomy | Kenhub. Available from: http://www.youtube.com/watch?v=X7xbuAN2XDk
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