THE KNEES

Try this now. 1. Experiment with deviations of knee alignment in standing with straight legs, then standing with bent legs. 2. Picturing the placement and function of these support structures, hypothesize and feel the effects of poor alignment: medial rotation of the tibia, hyperexten- sion of the knees, and X legs and O legs. Range of Motion of the Knee and Yoga Applications Before we look at the muscles, we will briefly name the ranges of motion of the knee, with associated yoga poses. If you are just beginning your study of anatomy, you can think of the knee as a hinge, bending (flexion) and straightening (extending, which in this case is returning to neutral from flexion). As much as possible,

align the center of the patella over the center of the toes as you bend your knee. This is called “tracking,” and it will train the knees to hinge safely. For beginners, establishing this pattern early in your yoga career is a worthwhile effort. If you are ready for a more nuanced view of the knees, consider the following smaller ranges of motion. The glide As we bend a knee, the distal end of the femur glides forward on the tibial shelf. As we extend the knee, it glides back again. To aid that movement in yoga, we can think of extending forward through the femur bone as we flex, as in poses like Virabhadrasana II and Parshvakonasana. Look at Figure 5.1, and picture the glide of the femur over the tibia. Figure 5.6 Hyperextension of the knee Normal Hyperextended Rotations Because the femoral condyles are not equal in size, the femur rotates a small amount as it goes through flexion and extension. Picture a stick with two balls on the end, one ball bigger than the other. If you hold the stick vertically and roll it forward and back on the balls, the stick will turn a bit as it rolls because of the uneven size of the balls. This is the effect when we flex and extend the knee. In flexion the femur rotates laterally and in extension it rotates medially. This is an advantage in poses like Virabharasana II and Parshvakonasana, both of which require lateral rotation and flexion. Virasana, however, demands medial rotation of the femur with the knee flexed.

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