238 A MANUAL OF ANATOMY 



upper border is therefore sloped inwards and slightly downwards. The 

 greater forward prominence of the outer part of the surface explains 

 why the patella is inclined inwards in extension of the knee-joint. 



The condyles are convex from before backwards and from 

 side to side. Posteriorly they become prominent, and on this 

 aspect the external condyle extends a little higher than the internal. 

 As viewed from below the external condyle is broad and short, 

 the internal being long and narrow. When the femur is held 

 vertically the internal condyle projects lower down than the 

 external, and this brings the two condyles upon the same horizontal 

 plane when the bone occupies its natural sloping position. The 

 outer border of the external condyle is very nearly in the same line 

 with the outer border of the patellar surface, and the outer border 

 of the internal condyle is in the same line with the inner border of 

 the patellar surface. The inner border of the internal condyle has 

 a convex outline, and at its anterior part it turns outwards to the 

 patellar surface. For the most part the condyles are parallel, 

 the exception being the front part of the internal condyle, which 

 inclines outwards to meet the patellar surface. 



The demarcation between the condylar surfaces and the patellar 

 surface is clearly marked at either side. The external condyle 

 is separated from the patellar surface by a slightly elevated line 

 and groove, extending outwards and slightly forwards from the 

 front and outer part of the intercondylar fossa to the outer border 

 of the cartilaginous surface, where there is a depression which 

 receives the anterior part of the external semilunar fibro-cartilage 

 during extension of the knee-joint. The internal condyle is separated 

 from the patellar surface by a line and groove, extending from 

 near the front and inner part of the intercondylar fossa forwards and 

 slightly inwards to the inner border of the cartilaginous surface, 

 at a point about i inch below the inner end of the upper border of 

 the patellar surface. At this latter point there is a depression which 

 receives the anterior part of the internal semilunar fibro-cartilage 

 during extension of the knee-joint. The line and groove just 

 referred to do not extend quite close to the intercondylar fossa. 

 The groove subsides, but the line sweeps backwards in a curved 

 manner along the outer part of the inner condylar surface, thus 

 marking off a narrow semilunar zone from the general tibial surface. 

 This zone lies close to the inner part of the intercondylar fossa, and 

 is known as the patellar facet. In extreme flexion of the knee- 

 joint, as in the position assumed by the miner when at work, the 

 patella by its inner vertical zone articulates with this facet, which 

 may be called the miner's facet. 



The outer surface of the external condyle towards the back part 

 presents the external tuberosity, which gives attachment to the long 

 external lateral ligament of the knee-joint. Immediately above 

 and behind the tuberosity is an impression ^r the outer head of the 

 gastrocnemius, and behind and below it there is a groove, called 

 the popliteal groove^ which is directed downwards and forwards. 



