ARTICULATIONS OF THE LOWER EXTREMITIES. 303 



fascia is increased and thickened by an aponeurosis, which 

 springs from the inferior extremity of the extensor muscles on 

 the thigh. The membrane thus formed covers both the patella 

 and its ligament, and extends on each side to the lateral liga- 

 ments of the joint, to which it adheres; it may be traced even 

 behind them, but there it becomes indistinct, loose, and blended 

 with common cellular and adipose membrane. The involu- 

 crum adheres strongly to the internal and external condyle?, 

 and to the head of the tibia; it has oblique fibres on the patella, 

 transverse ones on the ligament of the latter, and longitudinal 

 ones on each side. It is in contact with ihe synovial mem- 

 brane of the joint, except in the middle portion, where it is se- 

 parated from it by the patella, and its tendon, and some adi- 

 pose matter. It may be dissected without difficulty from the 

 subjacent parts, by which the ligament of the patella, and the 

 synovial membrane are brought into view. 



The Ligament of the Patella being situated at the fore part 

 of the articulation, though separated from the extensor muscles 

 by the intervention of the patella, is, neverthless, their tendinous 

 insertion into the leg. It arises from the whole inferior margin 

 of the patella, and is inserted into the tubercle of the tibia. It 

 consists in longitudinal, closely compacted fibres, of a character 

 entirely tendinous; the more superficial of them give a layer to 

 the front of the patella, and in the fracture of the latter some- 

 times prevent a separation of its fragments. In front, as just 

 mentioned, it is in contact with the involucrum generale; behind, 

 is a large mass of fat placed between it and the synovial mem- 

 brane of the joint; and on the same surface, but lower down, it 

 is in contact with a bursa mucosa fixed between it and the tri- 

 angular flatness of the tibia above the tubercle'. 



A posterior ligament, an internal and an external lateral liga- 

 ment, two crucial ligaments, two semi-lunar cartilages, and a 

 synovial membrane, compose the remaining apparatus of the 

 joint. 



The Posterior Ligament (Lig. Posticum,} is a fibrous expan- 

 sion on the back of the knee joint, which may be considered as 

 the proper capsular ligament at this point, and has its fibres ex- 



