I can see it now: you just won the official twist off on the dance floor at your Aunt Susan’s third wedding reception. She always said third time’s a charm and you were determined to prove your dedication to the celebration by showing all the guests your slick synovial moves. So there you are, ready to pop a calcaneus for your Dee Dee Sharp showdown, when all of a sudden a mysterious pain at the back of your popliteal fossa stopped you in your potato smashing tracks!
Well, it’s happened to the best of us, my friend. You knew you had to take a moment to sit this one out between asthmatic Cousin Jimmy and arthritic Grandpa Joe to palpate the reasons of potato smashing stress. Here’s what you found:
Sitting down in a chair with a flexed tibiofemoral joint, better known as your knee, you locate the lateral condyle of the right femur bone. The distal end of the femur has two knuckles called condyles and the lateral side is located to the outside of the knee. Directly below the lateral condyle is a protuberance,or tuberosity of a bone called the tibia, the bigger of the two lower leg bones. Follow the tuberosity to the proximal posterior aspect of the tibia better known as back of the upper calf. The back of the knee can be a very confusing proprioceptively, but it is a place that with little understanding and exploration can be figured out.
Superficially the gastrocnemius, like two big squishy worms stuck together, lies vertically down the back of the calf, deep to the soleus (also known as ‘the second heart’ that pumps blood from the leg to the heart. These two muscles along with the plantaris, a short bellied muscle with the longest tendon in the body, converge into the calcaneal tendon, or Achilles’ heel, to make up the musculature of the posterior inferior tibiofemoral joint. They create flexion of the knee and plantar flexion of the ankle. Behind these three flexors lies the potato culprit that mashed your dreams of twisting and 1960’s liberation: none other than the likes of the deep, short-bellied popliteus!
As the muscle’s name suggests, this triangular-like shaped muscle is located in the popliteal fossa at the posterior side of the knee. Though difficult to palpate one can attempt to maneuver around the gastrocnemius and soleus to strum at the diagonal fibers that stretch to its tendinous insertion on the posterior tibia. The popliteus has the important function of keeping your thigh bones connected to your shin bones, when the knee is in flexion during activities such as walking down hill, stairs, squatting, skiing, wearing high heels, practicing chair pose and doing any mid century dance moves.
The action of the popliteus is to flex the knee along with the other three flexors but most notably medially rotates the flexed knee just like in dance moves such as the twist or the mashed potato. When the muscle contracts, it medially rotates the lower leg and can assist to draw the heel toward the lateral side of the gluteal muscles in a swinging like motion just like this:
To find out how to get your groove back on stay tuned for my next article: How To Get The Pop In Your Popliteus!