ease, and
do not figure in the clinical features of these affections; Caird has
observed a case in which the cavity of the joint and the bursa beneath
the psoas were filled with loose bodies, many of which had undergone
ossification and gave a characteristic picture with the X-rays.

_Hysterical affections_ of the hip resemble those in other joints.

THE KNEE-JOINT

The knee is more often the seat of disease than any other joint in the
body.

The synovial membrane extends beneath the quadriceps extensor as a
cul-de-sac, which either communicates with the sub-crural bursa, or
forms with it one continuous cavity. When the joint is distended with
fluid, this upper pouch bulges above and on either side of the
patella, and this bone is "floated" off the condyles of the femur.
When there is only a small amount of fluid, it is most easily
recognised while the patient stands with his feet together and the
trunk bent forwards at the hip-joints, and the quadriceps completely
relaxed; the fluid then bulges above and on each side of the patella,
and its presence is readily detected, especially on comparison with
the joint of the other side.

On account of the great extent of the synovial membrane, a large
quantity of serous effusion may accumulate in the joint in a
comparatively short time, as a result either of injury or disease. The
villous processes and fringes may take on an exaggerated growth, and
give rise to pedunculated and other forms of loose body.

The bursae in the popliteal space, especially that between the
semi-membranosus and the medial head of the gastrocnemius, as well as
the sub-crural bursa, frequently communicate with the synovial cavity
of the knee and may share in its diseases.

As the epiphyses at the knee are mainly responsible for the growth in
length of the lower extremity, and are late in uniting with their
respective shafts--twenty-one to twenty-five years--serious shortening
of the limb may result if their functions are interfered with, whether
by disease or injury. The epiphysial cartilages lie beyond the limits
of the synovial cavity, so that infective lesions at the ossifying
junctions are less likely to spread to the joint than is the case at
the hip or shoulder, where the upper epiphysis lies partly or wholly
within the joint; disease in the lower end of the femur is more likely
to implicate the knee-joint than disease in the upper end of the
tibia.

One of the commonest causes of pro