336 Anatomy Applied to Medicine and Surgery, 



are, in addition, branches ascending in the interior of the 

 neck, and others along the retinacula or reflected por- 

 tions of the capsular ligament, but, in a fracture of the 

 neck, the latter two sources are cut off from the head, 

 and hence, there is not sufficient blood brought to this 

 fragment to promote bony union. Another possible ex- 

 planation is, that, since the neck is surrounded by synovial 

 membrane, and, since there is always more or less syno- 

 vitis present in fracture of the neck, it is, therefore, possible 

 for the effused fluid to wash away the exudate necessary 

 for callus formation, and, lastly, the movement, more or 

 less permitted, between the fragments might prevent bony 

 union. 



Fracture of ~the Shaft. The shaft is most often broken 

 in the middle third and generally in the upper part of this 

 portion of the bone. According to Hamilton, out of 146 

 cases of fractured femur, thirty belonged to the upper 

 third, eighty to the middle and thirty-six to the lower 

 third. The direction of the obliquity varies, being, gener- 

 ally, downwards and inwards, in the upper and middle 

 thirds of the shaft, and downwards and forwards, in the 

 lower third, and when union occurs, there is, generally, a 

 shortening of from one-half to three-quarters of an inch, 

 excepting in children in whom very little shortening can, 

 as a rule, be detected. 



Displacement, when due to muscular action, in fracture 

 of the thigh, may be explained as follows : When the frac- 

 ture is near, or at the neck of the bone, the contraction of the 

 glutei, adductors and pectineus, the rectus, gracilis, sarto- 

 rius, biceps, semi-tendinosus and semi-membranosus draw 

 up the lower fragment and produce shortening of the limb. 

 When the fracture is situated immediately below the lesser 

 tro chanter, the upper fragment is flexed by the action of 

 the psoas and iliacus, rotated outwards by the external 



