Be sure to check out our video on McMurray's Test below!
Menisci: Medial and lateral crescent shaped structure anterior to the tibial plateaus, which lie between the articular cartilage of the femur and tibia. The meniscus is an essential part component to normal knee functions. The menisci assist with many functions including: load transmission, shock absorption, joint lubrication and nutrition, secondary mechanical stability, and the gliding of movements (Dutton, Alford et. al).
Medial meniscus: Semilunar or U shaped medial meniscus. The medial meniscus is wider posteriorly than anteriorly. It is attached to the anterior and posterior tibial plateau by coronary ligaments. These ligaments connect the outer meniscal borders with the tibial edge and restrict movement of the meniscus. The medial meniscus also has an attachment to the deeper portion of the MCL and the knee capsule (Dutton, Alford et al.).
Lateral Meniscus: A “C” shaped structure that sits atop of the convex lateral tibial plateaus. It is smaller, thinner, and more mobile than the medial meniscus. Plays a role with the popliteus tendon, which supports it during knee extension and separates it from the joint. The periphery of the lateral meniscus attaches to the tibia, the capsule, and the coronary ligament, but not to the LCL. Two meniscofemoral ligaments, the ligaments of Humphrey and Wrisberg attach to the lateral meniscus (Dutton). These structures give support to the capsule during rotational movement of the tibia and stabilization of the meniscus. The lateral meniscus is associated with appearance of synovial filled cysts. These may occur following a minor injury to the meniscus and produce a small tear. Fluid then begins to congregate in the tear and is pushed deep into the meniscus. The swelling eventually produces a small bulge on the lateral side of the meniscus (Alford et al).
Role of the Menisci:
During knee motion, the menisci move on the tibial plateau with the femoral condyles to maintain joint congruence (Thompson). The inner sides of the menisci are attached by their anterior horns to the tibial plateau and move with the tibia. The body of each meniscus is fixed around the femoral condyle, therefore the meniscis move with the femur.
A torn meniscus is the most common cause of mechanical symptoms in the knee. These lesions generally occur when a patient attempts to run, twist, or change directions when weight bearing. They may also occur from contact to the lateral or medial part of the knee while the lower extremity is planted. For the aging population, meniscal tissue degenerates and makes it more susceptible to splitting from stress which results in horizontal tears. With a damaged meniscus ,the loads on the articular surface increase significantly which can result in great articular damage and degenerative arthritis (Alford et. al)
McMurray's Test (Meniscus Injury) (Dutton)
Patient Position: Supine fully relaxed
Examiner: Bring the hip and the knee into full flexion, using one hand on the plantar surface of the calcaneus and the other on the joint line of the knee to feel for positive signs. Four different sweeps should be made into full extension of the limb to target all areas of the meniscus:
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