216 



DISSECTION OF THE LEG. 



thrown into 

 folds named 

 ligaments, 

 mucous, 



and alar. 



Synovial 

 pouches : 

 two behind 



and one 

 before. 



Articular 

 fat; 



below 

 patella, 



use; 



above the 

 patella. 



Dissect 

 internal 

 ligaments. 



Ligaments 

 within the 

 capsule. 



of serous membranes, and sends a pouch between the tendon of the 

 popliteus and the external fibro-cartilage and the head of the tibia ; 

 it is also reflected over the strong crucial ligaments at the back of 

 the joint. 



There are three named folds of the synovial membrane. One in 

 the centre of the joint is the mucous ligament (a), which contains 

 small vessels and some fat, and extends from the interval between 

 the condyles to the fat below the patella. Below and on each side 

 of the patella is another fold alar ligament (b and c), which is 

 continuous with the former below the patella, and is placed over a 

 mass of fat : the inner (6) is prolonged farther than the outer by a 

 semilunar piece of the synovial membrane. 



At the back and front the articulation pouches are prolonged 

 beneath the tendons of muscles. Behind there are two, one on each 

 side, between the condyle of the femur and the tendinous head of 

 the gastrocnemius. On the front, the sac projects under the extensor 

 muscle one inch above the articular surface ; and if it communicates 

 with the bursa in that situation, as is usually the case, it will reach 

 two inches above the joint-surface of the femur. When the joint is 

 bent there is a still greater length of the serous sac above the patella. 



Fat around the joint. Two large masses are placed above and 

 below the patella, and a smaller quantity of fat surrounds the 

 crucial ligaments. 



The infrapatellar mass, the largest of all, fills the interval between 

 the patella with its ligament and the head of the tibia, and gives 

 origin to the ridges of the synovial membrane. From it a piece is 

 continued round the patella ; but it is larger at the inner margin 

 than at the outer, and overhangs the inner perpendicular facet of 

 that bone. This infrapatellar pad adapts itself to the varying shape 

 and extent of the angular interspace between the bones and the liga- 

 mentum patellae in the movements of the joint. 



The suprapatellar pad is interposed between the common extensor 

 tendon and the femur round the top of the synovial sac, and is 

 larger on the outer than the inner side. 



Dissection (fig. 83). The ligamentous structures within the 

 capsule will be brought into view, while the limb is still in the 

 same position, by throwing down the patella and its ligament, and 

 clearing away the fat behind it. In this step the student must be 

 careful of a small transverse band which connects anteriorly the 

 interarticular fibro-cartilages. 



The remains of the capsule and other ligaments, and the synovial 

 membrane, are next to be cleared away from the front and back of 

 the crucial ligaments, and from the fibro-cartllages. While cleaning 

 the posterior crucial ligament, the limb is to be placed flat on the 

 table with the patella down, and the student is to be careful of a 

 band in front of the ligament from the external fibro-cartilage, or 

 of two bands, one before and the other behind it. 



Ligaments within the capsule. The ligamentous structures within 

 the capsule consist of the central crucial ligaments, and of two plates 

 of fibro-cartilage on the head of the tibia. 



