14^ ARTHROLOGY. 



arises from the external condyle of the femur, and. passes over 

 the head of the tibia to the fibula; a synovial bursa lies between 

 it and the tibia. It is separated from the capsular ligament by 

 the tendon of origin of the popliteus. The internal lateral arises 

 from the internal condyle of the femur, and is attached to the 

 intero-lateral aspect of the head of the tibia. 



Capsular Ligament. — This name is usually applied to a mem- 

 braiious ligament enclosing the joint posteriorly, and attached to 

 the femur, tibia, lateral ligaments, and menisci. It is hj some 

 called tho posterior ligament. Anterior to this there is a pair 

 of membranes enclosing the joint antero- laterally. These are 

 generally described as the synovial membranes; bat as they are 

 considerably strengthened, and help to play the part of a capsular 

 lig-ament, it may be convenient to describe them as such. There 

 is therefore a complete capsular ligament investing the joint, 

 thickened posteriorly. 



The synovial apparatus is double, each side having its own 

 membrane, and. between the two are the crucial ligaments of 

 the joint.' Anteriorly, the synovial membranes contact that of the- 

 femoro-patellar joint, and it is found that sometimes the 

 synovial cavities are continuous with that of the latter. A large 

 quantity of fat fills up the space between the capsules and the 

 straight ligaments of the patella. The motions of this joint are 

 flexion and extension, and a certain amount of rotation, 

 permitted by the presence of the disss. 



TIBIO-FIBULAR ARTICULATION. 



This small articulation is formed by the facets on the adjacent 

 surfaces of the tibia and fibula, and is a diarthrodial joint. The 

 ligaments are a strong capsular one and the interossei, which 

 divide into superior and Inferior ; the former being a small 

 bundle at the upper third of the fibula ; the latter consists of a 

 membranous expansion, extending from the middle to the distal 

 extremity of the fibula. Between the two interosseous parts 

 pass the chief artery and vein of the region, the anterior tibial. 

 A ligamentous cord extends downwards from the fibula to the 

 external malleolus of the tibia, " where this cord bifurcates and 

 unites witli the two exter-iuil Literal ligaments of the tarsal joint" 

 (Bigot). Motion in tliis joint can hardly be said to exist. 



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