448 A MANUAL OF ANATOMY 



patellar surface of the femur may be felt when the knee-joint is 

 flexed, but it is somewhat obscured by the tendon of the quadriceps 

 extensor cruris. It is oblique in direction, and rises higher externally 

 than internally. The adductor tubercle is on the same level as the 

 outer part of the upper border of the patellar surface. A line 

 connecting these two points, and at the same time cutting the ad- 

 ductor tubercle into two, indicates the line of junction of the lower 

 epiphysis of the femur with the shaft at the twentieth year. The 

 external condyle of the femur, though not very prominent, may 

 be felt. The external tuberosity of the tibia forms a marked pro- 

 minence at the outer and anterior part of the knee-joint, and it here 

 presents a tubercle, or ridge, for the ilio- tibial band of the fascia 

 lata. The head of the fibula is easily felt below and behind the 

 external tuberosity of the tibia. The tubercle of the tibia is felt at 

 the upper end of the sharp anterior border or crest of the bone. 

 Its upper border is on the same level as the upper part of the head 

 of the fibula. It is to be noted that the internal tuberosity of the 

 tibia has a slight inclination backwards as well as inwards. 



The lower limit of the synovial membrane of the knee-joint 

 corresponds with the level of the tubercle, or ridge, on the anterior 

 and outer part of the external tuberosity of the tibia for the attach- 

 ment of the ilio-tibial band of the fascia lata. If this tubercle 

 cannot be felt, a transverse line just above the head of the fibula 

 indicates the lower limit of the membrane. In this direction the 

 membrane clothes the deep or posterior surface of the ligamentum 

 patellae in its upper half. Behind the lower end of this ligament 

 there is a bursa separating it from the upper smooth part of the 

 tubercle of the tibia. Superiorly the synovial membrane extends 

 upwards above the patella in the form of a large pouch upon the 

 front of the femur for about 2 inches above the upper border of 

 the patellar surface of the bone. This pouch lies beneath the tendon 

 of the quadriceps extensor cruris, and communicates with a bursa 

 which is situated immediately above it, and which extends upwards 

 for about another inch beneath the tendon. 



In extension of the knee-joint the patella is situated above the 

 level of the condyles of the femur. In flexion it lies over the inter- 

 condylar fossa. In extreme flexion the patella articulates chiefly 

 with the semilunar impression on the outer part of the tibial surface 

 of the internal condyle of the femur, close to the intercondylar fossa. 

 The particular part of the patella which so articulates is the inner 

 vertical zone on its posterior surface, immediately adjoining its 

 internal border. In flexion of the joint there is a depression on 

 either side of the ligamentum patellae, and also on either side of the 

 patella itself, the latter depression being greater on the inner than 

 on the outer side. In this position of the joint the anterior margin 

 of each tibial tuberosity is readily felt, and, above each, there is a 

 hollow which separates it from the corresponding femoral condyle. 

 In extension of the joint the depression on either side of the patella 

 is also manifest, being, as in flexion, greater on its inner side. The 



