Ill 



Description of the Bones of the Posterior Extremity. ■ 



Femur*. — The femur is a short, broad and very strong bone, flattened from 

 before backwards, with a subquadrilateral outline, but having the parallelism of 

 the two longest sides affected by the concavity of the inner one. The proximal 

 outline is nearly horizontal and at right angles to the lateral ones, but with the 

 inner angle rounded ofl^ and slightly expanded to form the head of the bone : 

 the distal outline runs parallel with the proximal one, the condyles being of equal 

 length, but the angles dividing it from the outer and inner borders are obliquely 

 truncated. The transverse diameter of the proximal end, taken across the head 

 and great trochanter, exceeds that of the distal end. 



The head, supporting the smooth surface presented to the acetabulum, is in form 

 hemispherical ; the articular hemisphere is directed obliquely upwards and in- 

 wards, encroached upon at the middle of its posterior margin by an oblong and 

 moderately deep depression for the round ligament ; the rest of its circumference 

 is shghtly sinuous, and anteriorly overhangs the shaft. The upper part of the 

 neck of the femur expands, as it passes obMquely from behind forwards to the 

 great trochanter, which scarcely rises above the horizontal line of the neck, and is 

 on a lower level than the head. This trochanter is flattened at its summit and 

 outer side, these surfaces meeting at a right angle : it is produced both forwards 

 and backwards, but chiefly in the latter direction, where it descends, like a 

 strong round column or buttress, along the outside of a large and deep cavity, be- 

 fore it subsides into the level of the shaftf . Viewed from the outer side, the broad 

 external rugged surface of the great trochanter hides the rest of the proximal 

 tliird of the femur from view, so much does it surpass that and every other part 

 of the bone in antero-posterior diameter. It gradually contracts to form the 

 strong external ridge, which descends, interrupted by only a slight emargination, 

 to be continued into that which surmounts the external condyle. The anterior 

 production of the great trochanter is narrower, and more rugged than the pos- 

 terior one : it is also flattened and separated by a ridge from the outer convex 

 surface of the process, with which it is placed nearly at right angles : the external 

 border of the shaft of the femur seems to be more immediately continued from 

 the lower angle of the anterior surface of the trochanter, and is slightly bent for- 

 * Plates XVII., XVIII., XIX. fig. 1. f Plate XVIII. 



