THE KNEE-JOINT 



28- 



Some fibres of the peroneus longus occasionally arise from the lower end of the ligament. The 

 posterior portion is 8 mm. (^ in.) behind the anterior. It is broader and less defined; fixed below 

 to the apex of the fibula, it inclines upward and somewhat backward, and ties down the popliteus 

 against the lateral condyle of the tibia, blending beneath the lateral head of the gastrocnemius 

 with the oblique popliteal ligament of the knee, of which it is really a portion. 



The oblique popliteal ligament or ligamentum Winslowii (fig. 317) is a broad 

 dense structure of interlacing fibres, with large orifices for vessels and nerves. 

 It is attached above to the femur close to the articular margins of the condyles, 

 stretching across the upper margin of the intercondyloid fossa, to which it is 

 connected by fibro-fatty tissue; it thus reaches across from the tibial to the 

 fibular collateral ligaments. Below, it is fixed to the border of the lateral condyle 

 of the tibia, to the bone just below the posterior intercondyloid notch, and to the 

 shaft of the tibia below the medial condyle, blending with the descending slip of 

 the semimembranosus and tibial collateral ligament. 



Superficially, an oblique fasciculus from the semimembranosus runs across the centre, passing 

 upward and laterally from near the back part of the medial condyle of the tibia to the lateral 



Fig. 318. — The Lower Extremity of the Femur (Anterior View) to show- the Rela- 

 tion OP the Articular Capsule op the Knee-joint (in red) to the Epiphysial Line. 



epicondyle of the femur, where it joins the lateral head of the gastrocnemius, a sesamoid plate 

 being sometimes developed at the point of junction. This slip greatly strengthens the obhque 

 popHteal ligament, of which, if not the chief constituent, it is at least a very important part. 



Its deep surface is closely connected with the semilunar menisci (especially the medial) and 

 coronary ligaments, and in the interval between the cartilages with the posterior crucial ligament 

 and fibro-fatty tissue within the joint. Superficially it forms part of the floor of the popliteal 

 space. A special band, the arcuate ligament, is sometimes found extending from the lateral 

 epicondyle to the oblique ligament. 



The articular capsule (fig. 319) is thin but strong, covering the synovial 

 membrane, and looking like a loose sac. It is attached to the femur near the 

 articular margin on the mecUal side, but further away on the lateral; it passes 

 beneath the fibular collateral ligament to join the sheath of the popliteus. Medi- 

 ally it joins the tibial collateral ligament. Below, it is fixed to the upper as well 

 as the medial and lateral borders of the patella and the anterior border of the 

 head of the tibia. It is strengthened superficially between the femur and patella 

 by an expansion from the articularis genu (suh-crureus) and is separated from 



