252 ANATOMY OF THE LOWER EXTREMITY 



tibia and the inter-articular cartilages, and is lined inter- 

 nally by the synovial membrane. 



The external lateral ligament is a rounded bundle of 

 fibres, extending between the external condyle and the head 

 of the fibula ; a second bundle is sometimes found posterior 

 to this, and called the short external lateral ligament. 



The internal lateral ligament is attached to the internal 

 condyle above, and the inner tuberosity of the tibia below ; 

 its limits are not distinctly marked ; the inferior internal 

 articular artery, and the tendon of the semi-membraiiosus, 

 pass beneath it. 



The anterior ligament, or ligamentum patellse, is attached 

 to the lower border of the patella above, and the tubercle 

 of the tibia below ; a bursa will be found beneath its in- 

 sertion into the tubercle. 



The posterior ligament, or ligamentum posticum Wins- 

 lowii, is formed chiefly by fibres of the tendon of the semi- 

 membranosus muscles, which pass across the joint to the 

 outer condyle ; a deeper set of fibres is continuous with the 

 general capsule. 



The knee-joint is to be opened by an incision along each side and 

 across the front, above the patella ; the patella and its ligament are 

 to be turned downward ; this exposes the synovial membrane and 

 inter-articular ligaments. 



The synovial membrane, coextensive with the capsule, 

 covers the cartilages of the bones, and all the inter-articu- 

 lar structures ; it forms a pouch on each side of the patella, 

 extending above and below it a distance sometimes as 

 great as two inches ; posteriorly it sends a pouch between 

 the head of the popliteus muscle and the tibia. A fold of 

 the synovial membrane, called the mucous ligament, ex- 

 tends from between the condyles to the fat below the 

 patella ; this is continued outward to the sides of the 

 patella, under the name of the alar ligaments. 



The crucial ligaments are two strong bands, the anterior 

 of which, arising from the depression in front of the spine 

 of the tibia, goes to the inner surface of the external con- 

 dyle, and the posterior from the depression behind the 

 spine to the inner surface of the internal condyle ; the in- 

 ternal ligament is larger than the external. The respective 

 insertions of the crucial ligaments are difficult to remem- 

 ber; the initial letters of the words, anterior external, 



