FEMUR. 



241 



prominent, and prolonged further upwards upon the front of the outer condyle. 

 The intercondyloid notch lodges the crucial ligaments ; it is bounded laterally 

 by the opposed surfaces of the two condyles, and in front by the lower end of 

 the shaft. 



Outer Condyle. The outer surface of the external condyle presents, a little 

 behind its centre, an eminence, the outer tuberosity ; it is less prominent than the 

 inner tuberosity, and gives attachment to the external lateral ligament of the 

 knee. Immediately beneath it is a groove, which commences at a depression a 

 little behind the centre of the lower border of this surface. The depression is 

 for the tendon of origin of the Popliteus muscle ; the groove in which this 

 tendon is contained is smooth, covered with cartilage in the recent state, and 

 runs upwards and backwards to the posterior extremity of the condyle. The 

 inner surface of the outer condyle forms one of the lateral boundaries of the 

 intercondyloid notch, and gives attachment, by its posterior part, to the ante- 

 rior crucial ligament. The inferior surface is convex, smooth, and broader than 

 that of the internal condyle. The posterior extremity is convex and smooth ; 

 just above the articular surface is a depression for the tendon of the outer head 

 of the Gastrocnemius, above which is the origin of the Plantaris. 



Inner Condyle. The inner surface of the inner condyle presents a convex 

 eminence, the inner tuberosity, rough, for the attachment of the internal lateral 

 ligament. Above this tuberosity, at the termination of the inner bifurcation 

 of the linea aspera, is a tubercle, for the insertion of the tendon of the Adductor 

 Magnus ; and behind and beneath the tubercle a depression, for the tendon 

 of the inner head of the Gastrocnemius. The outer side of the inner condyle 

 forms one of the lateral boundaries of the intercondyloid notch, and gives 

 attachment, by its anterior part, to the posterior crucial ligament. Its inferior 

 or articular surface is convex, and presents a less extensive surface than the 

 external condyle. 



Structure. The shaft of the femur is a cylinder of compact tissue, hollowed 

 by a large medullary canal. The cylinder is of great thickness and density in 

 the middle third of the shaft, where the bone is narrowest, and the medullary 

 canal well formed ; but above and below this, the cylinder gradually becomes 

 thinner, owing to a separation of the layers of the bone into cancelli, which 

 project into the medullary canal and finally obliterate it, so that the upper and 

 lower ends of the shaft, and the articular ex- 

 tremities more especially, consist of cancel- 

 lated tissue invested by a thin compact layer. 



The arrangement of the cancelli in the 

 ends of the femur is remarkable. In the 

 upper end (Fig. 172), they run in parallel 

 columns a a from the summit of the head to 

 the thick under wall of the neck, while a 

 series of transverse fibres b b cross the 

 parallel columns, and connect them to the 

 thin upper wall of the neck. Another series 

 of plates c c springs from the whole interior 

 of the cylinder above the lesser trochanter ; 

 these pass upwards and converge to form a 

 series of arches beneath the upper wall of the 

 neck, near its junction with the great tro- 

 chanter. This structure is admirably adapted 

 to sustain, with the greatest mechanical ad- 

 vantage, concussion or weight transmitted 



from above, and serves an important office in strengthening a part especially 

 liable to fracture. 



In the lower end, the cancelli spring on all sides from the inner surface of 

 the cylinder, and descend in a perpendicular direction to the articular surface, 

 16 



Fig. 172. - Diagram showing the 

 Structure of the Neck of the Femur. 



