Popliteus Muscle - “The Key of the Knee”
Updated: Sep 30
The popliteus muscle is often called "The Key of the Knee" because it is responsible for "unlocking" the knee when the leg is in an extended position. Besides this "unlocking" function, the popliteus muscle also helps to perform several critical actions during the gait cycle. Before we go over some of those actions, let's discuss some basic anatomy and biomechanics related to this important structure. This next section is for us anatomy geeks. Feel free to skip to the following section!
Article Index:
Anatomy & Bio Mechanics
Anatomy of the Popliteus Muscle
The popliteus muscle is a small but important muscle located in the posterior aspect of the knee joint.
Here are some key points about its anatomy:
Origin: The popliteus muscle originates at the lateral condyle of the femur and the posterior horn of the lateral meniscus.
Insertion: The muscle inserts on the tibia just proximal to the soleal line and just below the tibial condyles.
Innervation: The popliteus muscle is innervated by the tibial nerve.
Function: The primary function of the popliteus muscle is to unlock the knee joint by laterally rotating the femur on the tibia when the foot is in contact with the ground.
Biomechanics of the Popliteus Muscle
The popliteus muscle plays an important role in the biomechanics of the knee joint. Here are some key points about its function:
Unlocking the Knee: When the foot is in contact with the ground, the popliteus muscle laterally rotates the femur on the tibia to unlock the knee joint.
Medial Rotation: When the leg is not in contact with the ground, the popliteus muscle medially rotates the tibia on the femur.
Stabilization: The popliteus muscle helps to stabilize the knee joint during weight-bearing activities.
Gait Cycle: The popliteus muscle also plays a crucial role in the gait cycle by controlling the internal and external rotation of the tibia during walking and running.
The popliteus muscle is a small but important muscle with a significant role in the biomechanics of the knee joint. Its anatomy and function make it an essential component for unlocking the knee joint, stabilizing the joint during weight-bearing activities, and controlling the rotation of the tibia during the gait cycle.
Popliteal Fossa Anatomy - Palpation & Checking for DVT's
The video titled "Popliteal Fossa Anatomy - Palpation & Checking for DVT's" offers a comprehensive overview of the crucial anatomical features of the popliteal fossa. It covers essential palpation techniques and examination protocols to identify deep vein thrombosis (DVT) in this region, making it a valuable resource for both students and practitioners alike.
The Multi-Functional Popliteus Muscle
The popliteus muscle is a multi-functional muscle that plays a vital role in the normal gait cycle. Here are four essential functions of the popliteus muscle during gait:
External Rotation: The popliteus muscle helps produce external rotation of the femur during the propulsion phase of gait.
Prevention of Forward Glide: The popliteus muscle assists the posterior cruciate ligament (PCL) in preventing forward glide of the femur on the tibia.
Deceleration Extension: The popliteus muscle aids the gastrocnemius muscle with deceleration extension of the knee.
Internal Rotation: The popliteus muscle assists the subtalar joint in internally rotating the tibia during initial contact in the stance phase of gait.
Running Tip: Over-striding while running can cause undue stress on the popliteus muscle.
Clinical Considerations
Injury to the knee joint often involves the popliteus muscle, and it can manifest in several ways. Here are some of the most common signs and symptoms of a popliteus injury:
General Pain: Patients may experience general pain over the back and lateral side of the knee, particularly over the proximal aspect of the popliteus tendon. This pain can be exacerbated during physical activity or weight-bearing exercises.
Resisted Movement Pain: There may be pain on resisted knee flexion or internal rotation while supine. Patients may also experience pain with resisted external rotation of the leg when their hip and knee are flexed to 90 degrees, known as a positive Garrick Test.
Popliteal Space Pain: Patients may experience pain directly over the popliteal space, also known as the popliteal fossa. This pain may be caused by nerve or vascular injury, as well as inflammation or irritation of the popliteus muscle.
Diagnosis of popliteus injuries can be challenging, as these injuries may mimic other conditions. However, a thorough clinical exam and imaging studies can help differentiate popliteus injuries from other knee joint conditions.
Knee Examination - Effective Orthopaedic Testing
This video showcases effective orthopaedic testing techniques to diagnose common causes of knee pain. By utilizing orthopaedic examination procedures, practitioners can learn how to identify the source of knee pain and effectively manage it.
Motion Specific Release
Motion Specific Release (MSR) is a treatment system that integrates diverse therapeutic perspectives to resolve musculoskeletal conditions. It follows the EPIC paradigm and integrates areas such as orthopedic and neurological examination, fascial research, kinetic chain relationships, myofascial manipulation, fascial expansions, osseous adjusting, Traditional Chinese Medicine, and functional exercise programs.
The Popliteal Squat Release
The Popliteal Squat Release, a Motion Specific Release™ technique, can be a valuable tool in resolving popliteus injuries and improving the overall function of this important muscle. Given that knee injuries often involve the popliteus muscle, clinicians should consider utilizing this soft tissue procedure to effectively manage popliteus-related knee injuries.
Popliteus Muscle Release - Motion Specific Release
Motion Specific Release offers a targeted technique known as Popliteus Muscle Release to address the pivotal role of the popliteus muscle in knee joint function. As the muscle responsible for "unlocking" the knee during leg extension, the popliteus muscle plays a crucial role in the gait cycle, among other functions. The Popliteus Muscle Release can help improve the function of this vital muscle, benefiting patients with knee joint issues.
The Kinetic Chain
As part of a comprehensive approach to treating knee joint injuries, it is essential to assess and treat not only the popliteus muscle but also the surrounding soft tissues and joint structures within the larger kinetic chain. By addressing any imbalances or dysfunctions within the kinetic chain, clinicians can help restore proper movement patterns and alleviate stress on the knee joint. To this end, the following videos showcase related protocols that are commonly used in conjunction with popliteus muscle treatment to optimize patient outcomes.
Knee Release Protocol - Motion Specific Release
Each case of knee pain should be assessed and treated as a unique dysfunction that is specific to that individual. Certain cases will only involve local structures, while other cases can involve a much larger kinetic chain. The MSR procedures I am demonstrating are very effective at addressing knee pain.
The Power of Chiropractic Adjustments
Chiropractic Adjustment are powerful tools. When patients who suffer from chronic back pain receive care at regularly pre-planned intervals (Chiropractic Maintenance Care), then they do much better as compared to patients who only receive care during episodes of acute back pain.
Increasing Knee Joint Mobility - 4 Point Knee Joint Mobilization (MSR)
Increasing Knee Joint Mobility - Increasing knee joint mobility is critical if you are going to effectively address the body's full kinetic chain. In fact, we greatly reduce the effectiveness of any myofascial treatment if we don’t also address restrictions in joint mobility.
Exercises
Rehabilitation of the popliteus muscle hinges on a systematic approach to exercise. Begin with mobility exercises, transition to strengthening routines, and finally, focus on balance and proprioception exercises to ensure comprehensive recovery.
Mobility
A prime mobility exercise is the popliteus stretch. To do this, sit down and cross the leg you want to stretch over your other knee. Hold the ankle with one hand for stability, while using the other hand to press the knee downward, targeting the popliteus muscle. Additionally, hamstring stretches can have a positive indirect effect on the popliteus. The subsequent video showcases a hamstring myofascial release exercise frequently recommended to our patients.
Hamstring Self Myofascial Release - Lacrosse Ball
Hamstring restrictions are a common problem. This video shows you how to release your hamstrings using both pin and stretch techniques and cross-friction massage (with a lacrosse ball).
Strengthening
Strengthening exercises targeting the popliteus are pivotal in rehabilitation due to the muscle's essential role in knee stability and function. The popliteus not only facilitates internal rotation of the tibia during knee flexion, but it also acts as a safeguard, preventing hyperextension of the knee joint. By fortifying this muscle, one can enhance joint stability, reduce the risk of re-injury, and ensure smooth, coordinated movements of the knee, especially during activities that involve dynamic changes in direction or terrain. Below are example of exercise we could prescribe in certain cases.
4 Point Band Leg Strengthening Exercises
This TheraBand exercise routine is specifically designed to target and strengthen four crucial muscle groups: Adductor, Abductor, Flexor, and Extensor muscles. These muscle groups play a vital role in maintaining stability, facilitating movement, and enhancing overall functional performance.
Peterson Step-Up Knee Exercise
In this instructional video, we will be focusing on a targeted exercise designed to strengthen the vastus medialis oblique (VMO) muscle. The VMO, a crucial component of the quadriceps muscle group, plays a pivotal role in maintaining knee stability.
Balance
Balance exercises are a cornerstone of popliteus rehab due to the muscle's role in stabilizing the knee during weight-bearing activities. By enhancing balance and proprioception, these exercises fortify the popliteus and surrounding musculature, ensuring coordinated knee movements and reducing the risk of re-injury during dynamic tasks.
Improve Your Balance - Exercises for Beginners
Balancing exercises are crucial components in both Rehabilitation and Sports Performance training. These exercises should not be overlooked, as they can bolster one's capacity to stabilize the body during functional movements.
Conclusion
In conclusion, the popliteus muscle plays a crucial role in knee joint function, contributing significantly to unlocking the knee during leg extension and other essential actions in the gait cycle. As such, any knee injury warrants an assessment of the popliteus muscle's involvement. Fortunately, effective soft tissue procedures, such as Motion Specific Release and Popliteus Muscle Release, can help resolve popliteus injuries and enhance overall function.
To optimize outcomes, it is also essential to consider the broader kinetic chain relationships and incorporate exercises and protocols that promote mobility, strength, balance, and proprioception. By taking a comprehensive approach, clinicians can help patients achieve better knee joint health and function. The "Knee Rehab" playlist provides a useful resource containing exercises that can help improve knee joint function and alleviate pain. With a thorough understanding of the popliteus muscle's role in knee joint function and effective treatment approaches, clinicians can help their patients achieve better outcomes and improved quality of life.
References:
Abelson B, Abelson K, Mylonas E. A Practitioner's Guide to Motion Specific Release: Utilizing Fascial Expansions, Acupuncture and Manual Therapy. 1st ed. Rowan Tree Books; 2018.
Azzopardi C, Kiernan G, Botchu R. Imaging review of normal anatomy and pathological conditions involving the popliteus. J Clin Orthop Trauma. 2021;18:224-229. PubMed
Farrell C, Kiel J, Seemann L, Pujalte GGA. Popliteus tendon injuries. Orthopedics. 2023;46(4):e193-e198. PubMed
Maniar AR, White AE, Musahl V, Ranawat A. Posterolateral corner of the knee: an update on current evaluation and management strategies. J Am Acad Orthop Surg. 2024;32(1):e13-e23. PubMed
Morrissey D, Knapik DM. Prevalence, mechanisms, and return to sport after isolated popliteus injuries in athletes: a systematic review. Orthop J Sports Med. 2022;10(2):23259671211073617. PubMed
Nyland J, Lachman N, Kocabey Y, Brosky J, Altun R, Caborn D. Anatomy, function, and rehabilitation of the popliteus musculotendinous complex. J Orthop Sports Phys Ther. 2005;35(3):165-179. PubMed
Porrino J, Sharp JW, Ashimolowo T, Dunham G. An update and comprehensive review of the posterolateral corner of the knee. Radiol Clin North Am. 2018;56(6):935-951. PubMed
Schweller EW, Ward PJ. Posterolateral corner knee injuries: review of anatomy and clinical evaluation. J Am Osteopath Assoc. 2015;115(12):725-731. PubMed
Shahabpour M, et al. Comprehensive review of the anatomy, function, and imaging of the popliteus and associated pathologic conditions. Radiographics. 2014. PubMed
Chahla J, Murray IR, Robinson J, et al. Posterolateral corner of the knee: an expert consensus statement on diagnosis, classification, treatment, and rehabilitation. Knee Surg Sports Traumatol Arthrosc. 2019;27:2520-2529. This consensus is also cited by the recent anatomical literature.
Disclaimer:
The articles and embedded videos on the MSR website are provided for educational and informational purposes only. They are not a substitute for individualized assessment, diagnosis, or treatment by an appropriately qualified healthcare professional.
Some videos demonstrate clinical examination and manual therapy procedures intended for licensed or regulated healthcare professionals with appropriate training. These procedures should be performed only within the practitioner’s legal scope of practice and should not be attempted as self-treatment.
Viewing or using this content does not establish a practitioner-patient relationship. If you have questions about a medical condition or symptoms that are new, severe, or worsening, consult an appropriately qualified healthcare provider.
MSR is not responsible for decisions made or actions taken solely on the basis of this educational content. For complete information about website use, third-party links, privacy, and legal terms, please review the MSR Terms of Use, Privacy Policy, and full website disclaimer.
DR. BRIAN ABELSON, DC. - The Author
Dr. Brian Abelson is a chiropractor, author, and educator with more than 30 years of clinical experience in musculoskeletal care, rehabilitation, and sports performance. His educational work focuses on musculoskeletal conditions, human movement, sports biomechanics, and evidence-informed approaches to treatment and rehabilitation.
He is the developer of Motion Specific Release (MSR) and Clinical Director of Kinetic Health in Calgary, Alberta, Canada.
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