442 



SURGICAL APPLIED ANA TOMY. [Chap. xxi. 



is shown in the diagram (Fig. 47), where it will be 

 seen that the enlargement of the internal condyle 

 is due almost entirely to increased growth in the 

 diaphysis. 



The patella. Fractures. This bone is more 

 often broken by muscular violence than is any other 

 in the body. Although the patella may be fractured 



Fig 1 . 47. A, Normal femur ; B, femur in an advanced case of knock-knee, 

 showing the enlargement of the internal condyle. The dotted line 

 in each case represents the line of the epiphysis. 



by both muscular and direct violence, it would appear 

 that the former is the agent that most often pro- 

 duces the lesion. Thus, in 127 cases of simple trans- 

 verse fracture collected by Hamilton, he considers that 

 muscular action was the cause of the injury in 106 in- 

 stances. The form of fracture due to muscular violence 

 is very uniform. It is nearly always transverse, simple, 

 and through the centre of the bone, or just above that 

 point or just below it. Fractures due to direct violence 

 may present the same appearance, but they are more 

 often starred, or oblique, or even longitudinal. Ex- 

 periments upon the cadaver show that a simple trans- 

 verse fracture about the centre of the bone cannot be 

 produced with any degree of certainty by a direct 

 blow. The position of the knee that most favours 



