Chap, xix.] THE UPPER END OF FEMUR. 407 



part very rarely indeed unite by bone. Blood is brought 

 to the head of the bone by the cervix, the reflected 

 parts of the capsule, and the ligamentum teres. When 

 the first two sources of blood supply are cut off by 

 the fracture the third does not appear to be sufficient 

 to allow of great reparative changes taking place 

 in the upper fragment. The fractures that heal by 

 bone are probably either impacted, or subperiosteal, 

 or not wholly intracapsular. 



2. With regard to fractures at the base of the 

 neck, it must be remembered that a wholly extra- 

 capsular fracture of the neck of the femur is an 

 anatomical impossibility. If the fracture is wholly 

 without the capsule, then it must involve a part 

 of the femoral shaft, and cannot be entirely through 

 the cervix. In the front of the bone the capsule is 

 attached to the femur along a part of the inter- 

 trochanteric line, and strictly follows the line of 

 junction between the cervix and the shaft. Behind, 

 the capsule is inserted into the neck some half of an 

 inch in front of the posterior inter- trochanteric 

 line. It is therefore possible for a fracture of 

 the neck to be extracapsular behind, but not in 

 front, and many of these lesions at the base of the 

 neck have this relation to the capsule. The Y ligament 

 is so thick, being in one place about a quarter of 

 an inch in thickness, that a fracture involving the 

 base of the cervix may run between its fibres at their 

 attachment, and be neither extra- nor intra-capsular. 

 When fractures at the junction of the neck and shaft 

 are impacted, the upper fragment, represented by the 

 compact and relatively small cervix, is driven into the 

 cancellous tissue about the great trochaiiter and upper 

 end of the shaft. As a result of this impaction the 

 trochanter may be split up, and the bones may 

 become free again through the extent of thiy 

 splintering. 



