1448 



CLINICAL AND TOPOGRAPHICAL ANATOMY 



part of the medial femoral epicondyle the adductor tubercle and the vertical tendon of the ad- 

 ductor magnus can be felt during flexion. This bony point is a guide to the lower epiphysis, 

 the ossification of which and its occasional exostosis have been mentioned at p. 1442. The 

 medial aspect of this epicondyle faces practically in the same direction as the head of the femur. 



Ligamentum patellae and tuberosity of tibia. — These, in a well-formed leg, 

 should, with the centre of the ankle-joint, be all in the same straight line, a useful 

 point in the adjustment of fractures. (Holden.) Behind the upper half of the 

 ligament is the infrapatellar pad of fat; below, the lower half is separated from the 

 tibia by a deep bursa. The tuberosity (tubercle) of the tibia is on a level with the 

 head of the fibula. 



[Prepatellar bursa. — This usually protects the lower part of the patella and upper part of 

 the ligamentum patellae. It is liable to be enlarged in those who habitually kneel much, the 

 enlargement being either fluid or solid, and occasionally, in tertiary syphilis. Its close connec- 

 tion with the patella and, at the sides, with the joint itself, is to be remembered in infective 

 inflammations of the bursa. Usually the deep fascia, passing off from the sides of the patella 

 upward to the thigh and downward to the leg, serves to conduct inflammation away from the 

 joint. 



S3movial membrane (fig. 1167). — This, the largest of the synovial membranes, 

 forms a short cul-de-sac above the patella, between the quadriceps extensor and the 

 front of the femur, this process reaching about 2.5 cm. (1 in.) above the trochlear 

 surface of the femur. At its highest point this cul-de-sac communicates with an- 



FiG. 1166. 



-Horizontal Section of the Knee-joint. 

 Prepatellar bursa 



Patella 



(One-half.) (Braune.) 



Fibular collateral lig. 



Lateral condyle of femur 



Biceps 

 Gastrocnemius, lateral head 



Peroneal n. 



Tibial n. 

 Semimembranosus 



Tibial collateral lig. 

 Medial condyle of femur 

 M. sartorius 



Great saphenous vein 

 Gastrocnemius, medial head 

 Tendon of gracilis 



Tendon of Semite ndinosus 



\ 



other synovial, bursa-like sac lying between the quadriceps and front of the femur. 

 Thus, synovial membrane will usually be met with 6.2 cm. (2| in.) or more above 

 the trochlear surface or the upper border of the patella when the limb is extended. 

 Flexing the joint draws the membrane down very slightly. During extension, the 

 above pouch is supported by the articularis genu (subcrureus). Traced down- 

 ward, the membrane reaches the level of the head of the tibia, being separated in 

 the middle line from the upper part of the ligamentum patellae by fat. It here 

 gives off to the intcrcondyloid notch the patellar synovial fold (ligamentum mu- 

 cosum), with its free lateral prolongations, the alar folds (ligamenta alaria). 

 These three so-called ligaments contain fat, the processes not only padding gaps, 

 but also meeting concussions. 



The enlargement of these processes, under conditions not yet understood, may certainly 

 be a cause of 'internal derangement,' and simulate a loosened meniscus. But the synovial 

 membrane of this joint is not only the largest: it is also the most complicated, a fact accounting 

 for the grave peril of infective arthritis, and the well-known difiiculty of effective drainage and 

 cleaiising this joint. Thus 'it pusses over the greater portion of the crucial ligaments, but the 

 posterior surface of the posterior crucial, which is connected by means of fibro-areolar tissue 

 to the front of the ligamentum posticum, and the lower portions of both crucial ligaments, where 

 they arc united togetlier, of course cannot receive a complete covering from the membrane., 

 (Morris.) 



From the above ligaments the membrane is conducted, lining the lower part 

 of tlie capsule and other ligaments, to the semilunar cartilages, first over their 



