The Popliteus Muscle – Why does the back of my knee hurt?

The knee is one of the most complex joints in the human body. It is impossible to summarize such a topic with the understanding of only one muscle. However, certain muscles in the human body appear to be more important then others. With regards to the knee the Popliteus is one of these muscles. In this column I will attempt to explain the importance of the Popliteus Muscle in an injured knee and the rehabilitative process.

Anyone can open an anatomy textbook and retrieve the basic information about a muscle so how about I save you some time?

Popliteus Muscle:

•O – Lateral Surface of the lateral condyle of the femur

Attachment to the lateral meniscus

•I – Upper part of the posterior surface of the tibia

•A – Medial rotates the tibia

•Inn – Tibial Nerve (Moore, 2006)

Basic anatomy has its importance but to truly understand injuries one has to grasp the concept of muscles working in synergy together. Sometimes this ideology is referred to as the Kinetic Chain.

Some of the most important anatomical aspects of the Popliteus muscle will not be found in your basic textbook but in research. The Popliteus muscle is one of the most researched muscles in the knee and is always being debated upon its main role. Here are some important anatomical concepts you should know.

1. The Popliteus muscle plays an important role in “unlocking” the knee joint. When flexion and extension occurs the Popliteus is involved in rotating the Tibia and Femur. This action allows the two bones to deviate from one another and now the bones will not “collide” or “lock”. This mechanism leads to a smooth movement of flexion and extension throughout the knee.

This gives good indication to the importance of soft tissue therapy to the Popliteus muscle. When patients present with injuries that don’t allow a smooth or full range of motion the Popliteus muscle could be the culprit. With a knee that is “catching” the Popliteus muscle should be “released”. Releasing the Popliteus muscle can be done with heat, stretching, Myofascial Release Therapy, Active Release Technique or Graston Technique. (Manual Therapy Techniques)

2. The Popliteus muscle is what we call a “feed forward” muscle. Other “Feed Forward” muscles include the Multifidus in the back and Supraspinatus muscle in the shoulder. These are muscles that can actually “turn on” or “fire” before movement even occurs amongst the joint. Furthermore, these muscles have a high amount of receptors making them very important for proprioception and balance training. This is important to know because any patient who has an “unstable” joint or a past knee dislocation can vastly benefit from a rehabilitative program which exercises the Popliteus muscle.

In addition, this knowledge is a good indication that athletes may benefit from a preseason exercise routine, which involves the Popliteus muscle. By training a muscle involved in proprioception this may lower the incidence of knee injuries. This same concept is already being explored with preseason prevention of ankle injuries and acl tears by certain workout regiments.

3. The Popliteus muscle also works in synergy with the posterior cruciate ligament (PCL). Anatomical studies have shown that by actually cutting the Popliteus muscle tension increased in the PCL. The same is true otherwise that by increasing the force through the Popliteus, tension has been lowered in the PCL. This concept makes sense when you observe the following picture. When you look at the Popliteus and PCL together they almost both make a hammack for the knee joint allowing the bones to rest on their surfaces. It makes sense that if you were to injury, tear or have one weak the other would need to support the load.

This details the fact that by maybe strengthening the Popliteus muscle PCL injuries would decrease. Furthermore, if you have a weak and dysfunctional Popliteus you may develop PCL insufficiency or obtain an injury in the future.

Need more details? The Popliteus also:

- helps in movement of the lateral meniscus

-Is involved in posteriorlateral stability of the knee

-Plays an important component in down hill running

-Has attachments to all of the following

–Distal MCL

–Fibular Head

–Lateral Meniscus

–PCL

–Femur

–Tibia

These are just a few concepts of why I believe the Popliteus is thee most important muscle of the knee. Even if the muscle itself is not injured addressing it may give significant results. The old concept of only treating what is injured is dead and understanding the body as a whole is starting to evolve.

So how do I exercise/rehabilitate the Popliteus muscle?

Tune in for a rehab protocol of the Popliteus next blog

Nyland, J. (2005). Anatomy, Function, and Rehabilitation of the Popliteus Musculotendinous Complex Journal of Orthopaedic and Sports Physical Therapy DOI: 10.2519/jospt.2005.1414