Anatomy – Concave Convex Law 2

One of the staples of kinesiology is the convex-concave rules of joint motion. It states that when a convex surface moves on a concave surface, the convex surface rolls one way and glides the opposite direction. If a concave surface moves on a convex surface, the concave surface rolls and glides in the same direction.

Working with Concave-Convex Law in the pelvis and femur, we can help create stability and a foundation to open the hip. This protects the knee and ankle from too much rotation.

Joint congruence is the measurement of two opposing joint surfaces as they relate to one another considering the contour of each bone at their interface. When looking at a joint, look for restrictions and lack of stability. Note in a shoulder if there is increased laxity (potential subluxation) in one direction and increased stiffness in another. Mobilize the hypomobile direction if you find one.