CHAPTER 5

That concludes the basic list of the most important knee muscles. For those who want to go further, here are some other interesting elements of the knee joint (two muscles and one common tendon). • The popliteus muscle, the deepest muscle of the knee, runs diagonally across the back of the knee, attaching to the lateral femoral condyle and the up- per inner tibia (see Figure 5.12). When it contracts, it medially rotates the tibia in relation to the femur. Its main claim to fame in the muscular teamwork of the knee is that it “unlocks” the knee from extension into flexion.

Plantaris

Popliteus Soleus

Lateral Figure 5.12 Plantaris and popliteus muscles attachment to femoral condyle Medial attachment to femoral condyle Achilles tendon • The plantaris muscle has the distinc- tion of having a very small belly but the longest tendon of any muscle in the body (see Figure 5.12). Its belly parallels the larger, deeper popliteus, running diagonally from the outer fem- oral condyle toward the inner knee, but its tendon extends all the way down to join into the Achilles tendon behind the ankle. You can feel it at the back of the knee, between the two gastrocne- mius tendons. It medially rotates the knee and assists in knee flexion. Figure 5.11 Gastrocnemius muscle

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