with slight forward angulation at the seat of fracture. By
the end of a month sufficient callus has formed to prevent
re-displacement, and if the counter-weight is gradually diminished the
two fragments sag back together into a normal alignment (J. N. J.
Hartley). A double-inclined plane (Fig. 70), with extension applied in
the axis of the thigh, gives satisfactory results.

[Illustration: FIG. 70.--Adjustable Double-inclined Plane.]

DISLOCATION OF THE HIP

It is unnecessary for our present purpose to attempt a comprehensive
classification of the numerous varieties of dislocation that have been
met with at the hip-joint. It will suffice if we divide them into
those in which the head of the femur passes backward, and comes to
rest on the dorsum ilii, or in the vicinity of the great sciatic
notch; and those in which it passes forward and comes to rest in the
obturator foramen, or on the pubes (Fig. 71).

[Illustration: FIG. 71.--Diagram of the most common Dislocations of
the Hip.]

The backward are much more common than the forward dislocations, in
contrast to what obtains at the shoulder, where the forward varieties
predominate.

On account of the great strength of the hip-joint, dislocation is by
no means a common injury. It occurs most frequently in strong adults
after the epiphyses have ossified, and before the bones have commenced
to become brittle; and it is much more common in men than in women. It
is invariably the result of severe violence, the limb at the moment
being in such a position that the ligaments are on the stretch and the
muscles taken at a disadvantage. The head of the femur usually leaves
the joint at the lower and back part, where the socket is most shallow
and the ligaments weakest. The ligamentum teres is almost always torn
from its femoral attachment, and one or more of the muscles inserted
in the region of the trochanters may be ruptured. The [inverted
Y]-shaped ligament, on the other hand, is seldom torn, and so long as
it remains intact the dislocation belongs to one or other of the types
above named. All atypical dislocations, such as the supra-cotyloid,
infra-cotyloid, ilio-pectineal, are due to rupture of some part of the
[inverted Y]-ligament, and are so rare as not to call for individual
description. The central dislocation of German authors, in which the
head is driven through the floor of the acetabulum, is described on
page 126.

Like other dislocations, those of the hip m