슬관절 반월상연골판의 구조 및 운동

ANATOMY The medial meniscus is semicircular and is narrower than the nearly circular lateral meniscus. In prenatal period the menisci are very cellular and highly vascularized throughout the subtances. After skeletal maturity, the peripheral vascularized connec- tive tissue constitutes from outer 1/3 of the total width. This vascular zone attach the meniscus to the joint capsule and probably provides the oxygen and nutrition to the outermost portion of the meniscus. The remaining (termed the midsubstance) is made up of avascular, aneural, and alymphatic fibrocartilage consisting of cells (fibrochond- rocytes) surrounded by the abundant extracellular matrix. The extracellula matrix is composed mainly of Type 1 collagen, with small quantities of proteoglycans, matrix glycoproteins and elastin. The appearance of the fibrochondrocyte is similar to chon- drocyte, yet they synthesize a fibrocartiagenous matrix. MOVEMENTS OF THE MENISCUS Flexion causes the meniscus to slide posteriorly in the tibial plateau. Because of its tight fixation to the joint capsule and medial collateral ligament, the medial meniscus is considerably less mobile fhan the lateral meniscus. With extreme flexion the posterior horn of the medial meniscus is compressed between femur and tibia and can be injured easily. A combination af sudden uncontrolled rotation and flexion-extension motion cause the injury of the meniscus, usually longitudinal tear in the medial meniscus and transverse or langitudinal tear in the lateral meniscus.