s broken off, it may give rise to a loose body. In advanced cases
with destruction of the cartilages, there may be movement from side to
side, with grating of the articular surfaces.

In the early stages, treatment consists in limiting the movements of
extension by means of a splint provided with a hinge that locks at
thirty degrees from full extension and vigorous massage of the
quadriceps. In the dry, creaking forms of arthritis, the symptoms are
relieved by introducing liquid vaseline into the joint. When the
symptoms are due to the presence of fringes and loose bodies, these
may be removed by operation. When the disease is of a severe type, and
is confined to one knee, the question of excising the joint may be
considered.

_Bleeder's knee_, _Charcot's disease_, _hysterical knee_, and _loose
bodies_ in the joint have already been described.

THE ANKLE-JOINT

There is a common synovial cavity for the ankle and the inferior
tibio-fibular joints. The epiphysial cartilage of the tibia lies above
the level of this synovial cavity, but that of the fibula is included
within its limits (Fig. 93). The talus is related to three
articulations--the ankle above, the talo-navicular joint in front, and
the calcaneo-taloid joint below. The tendon sheaths, especially those
of the peronei and of the tibialis posterior, are liable to be
infected by the spread of infective disease from the joint.

#Tuberculous Disease.#--Tuberculous disease at the ankle is met with
at all ages. In the majority of cases the disease affects both bone
and synovial membrane. Gross lesions in the bones are comparatively
rare, and are chiefly met with in the head or neck of the talus.

_Primary synovial disease_ usually exhibits the features of white
swelling, projecting beneath the extensor tendons on the dorsum, and,
posteriorly, filling up the hollows on either side of the tendo
Achillis and below the malleoli (Fig. 126). The foot may retain its
normal attitude, or the toes may be pointed and adducted. The calf
muscles are wasted, there is little complaint of pain, and the
movements of the joint may be so little interfered with that the
patient can walk without a limp. When the disease involves the
articular surfaces, there is pain and sensitiveness, the movements are
restricted or abolished, and the patient is unable to put the foot on
the ground.

[Illustration: FIG. 126.--Tuberculous Disease in a man aet. 35, of six
weeks' duration.]

_A pr