Orthopaedic Surgeon

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Menisci

The Menisci (semilunar fibrocartilages) are the shock absorbers of the knee. The also contribute to the stability of the knee (secondary stabilisers) by deepening the surface of the tibia to more closely match the roundness of the condyles of the femur (thigh bone). The outside edge of each meniscus is thick, convex, and attached to the inside of the capsule of the joint. The inner edge is thin, concave, and free. The top surfaces of the menisci are concave (and in contact with the condyles of the femur) while their under surfaces are flat and rest upon the tibia. Both surfaces are smooth and covered by synovial membrane. Each meniscus covers approximately the peripheral two-thirds of the corresponding joint lining surface of the tibia.

Medial Meniscus

The medial meniscus (meniscus medialis; internal semilunar fibrocartilage) is nearly semicircular in shape and broader behind than in front. The front end is thin and pointed and attaches to the anterior intercondyer fossa of the tibia (in front of the ACL). It's back end is fixed to the posterior intercondyloid fossa of the tibia, between the attachments of the lateral meniscus and the posterior cruciate ligament (PCL).

Lateral Meniscus

The lateral meniscus (meniscus lateralis; external semilunar fibrocartilage) is nearly circular and covers a larger portion of the joint lining surface than the medial one. The Popliteus tendon sits between the lateral meniscus and the lateral collateral ligament (LCL).  Its front end is attached in front of the intercondyler eminence of the tibia and is found lateral to and behind the anterior cruciate ligament.  The front attachment of the lateral meniscus is twisted on itself so that its free margin looks backward and upward, its front end resting on a sloping shelf of bone on the front of the lateral process of the intercondyler eminence. Close to its back attachment it sends off a strong band, the ligament of Wrisberg which passes upward and towards to cetre of the knee, to be inserted into the medial condyle of the femur, immediately behind the attachment of the posterior cruciate ligament (PCL). Occasionally a small band passes forward to be inserted into the lateral part of the anterior cruciate ligament (ACL). The lateral meniscus gives off from its anterior convex margin a band which forms the transverse ligament.

 

See also Meniscal Tears

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