and crepitus elicited. In oblique fractures, the pointed
lower end of the proximal fragment may transfix the quadriceps
extensor muscle and may be felt under the skin, or it may perforate
the skin and thus render the fracture compound. It should be
disengaged by fully flexing and making traction on the knee. The thigh
is shortened to the extent of from 1/2 to 1 inch.

The popliteal vessels lie so close to the bone that they are liable to
be torn by the displaced distal fragment, giving rise to the usual
signs of ruptured artery. Sometimes, owing to the feeble state of the
circulation from shock, the bleeding does not take place at the time
of the accident, but ensues some hours later. The vessels may merely
be pressed upon by the displaced bone, but the nutrition of the limb
beyond is endangered and gangrene may ensue if early reduction be not
effected.

_Treatment._--The small size of the distal fragment, its depth from
the surface, and the accompanying effusion into and around the joint,
render its control difficult. In the majority of cases the two
fragments can only be brought into apposition when the knee is flexed
on the thigh and the thigh on the pelvis, and it is almost always
necessary to carry out the reduction under anaesthesia.

In the few cases in which the fragments can be accurately approximated
in the extended position of the limb, retention may be effected by
means of a box splint reaching well up the thigh (p. 180).

In the majority, however, flexion is necessary, and a Thomas' knee
splint with flexion attachment bent to an angle of 30 deg. (Fig. 81) and
extension by means of ice-tong callipers secures the best apposition.
If this apparatus is not available the limb must be fixed on a
double-inclined plane, so constructed that the angle of flexion can be
adjusted to meet the requirements of the individual case (Fig. 70).

[Illustration: FIG. 81.--Extension applied by means of ice-tong
callipers for Fracture of Femur.]

Hodgen's splint, bent nearly to a right angle, may also be employed.

A careful watch must be kept on the circulation of the limb during the
first few days, lest it be interfered with by the pressure of the
apparatus.

In a considerable number of cases these means of retaining the
fragments in apposition prove ineffectual, and it is necessary to have
recourse to operative measures for mechanical fixation. Division of
the tendo calcaneus (Achillis) is not to be recommended as a m