During the McMurray's test, external rotation of the tibia stresses which meniscus?

In the context of McMurray's test, external rotation of the tibia specifically stresses the medial meniscus. This is due to the anatomical positioning and function of the menisci in the knee joint. The medial meniscus is more firmly attached to the surrounding structures, particularly the medial collateral ligament, making it more susceptible to injury during certain movements, including twisting motions that occur when the tibia is externally rotated.

During McMurray's test, the clinician rotates the tibia while applying a valgus stress, which can create a situation where the medial meniscus is compressed between the femur and tibia. If there’s a tear or dysfunction present, the patient might experience a palpable click or pain indicating injury to the medial meniscus. Hence, the external rotation specifically applies stress to this meniscus because of its location and its relationship with the knee's surrounding ligaments and structures.