Normal anatomy can be demonstrated with exquisite detail. The human knee permits flexion and extension of the leg. The proper functioning of its many components are required for motion, stabilization, and cushioning. The medial and lateral menisci are C-shaped structures composed of fibrocartilage that fill in the space at the articulation between the end of the femur at the top of the tibia. They serve to stabilize the joint, absorb shock, and guide the movements of the joint.
Meniscal tears can develop as the result of an acute injury.
However, many tears are degenerative in origin and are the result of years of chronic stress on the joint during normal use. The normal meniscus has a dark, triangular appearance. On MR images, a torn ACL can appear as discontinuity or complete absence of the ligament, which is frequently replaced by an amorphous collection of edematous tissue. Steven H. Brick, M.D. Drs.