e necessary nutriment from the surrounding fluid. The size
and number of the bodies vary widely. Single specimens have been known
to attain the size of the patella. The smaller varieties may number
considerably over a hundred.

[Illustration: FIG. 167.--Loose Body from Knee-joint of man aet. 25.
Natural size.

a = Convex surface. b = Concave surface.]

In arthritis deformans a rarer type of loose body is met with, a portion
of the lipping of one of the articular margins being detached by injury.
In Charcot's disease, bodies composed of bone are formed in relation to
the capsular and other ligaments, and may be made to grate upon one
another.

The _clinical features_ in this group are mainly those of the disease
which has given rise to the loose bodies, and it is exceptional to meet
with symptoms from impaction of the body between the articular surfaces.
Treatment is to be directed towards the primary disease in the joint, as
well as to the removal of the loose bodies.

[Illustration: FIG. 168.--Multiple partially ossified Chondromas of
Synovial Membrane, from Shoulder-joint, the seat of arthritis deformans,
from a man aet. 35.]

_Loose Bodies in Joints which are otherwise healthy._--It is in joints
otherwise healthy that loose bodies causing the classical symptoms and
calling for operative treatment are most frequently met with. They occur
chiefly in the knee and elbow of healthy males under the age of thirty.
The complaint may be of vague pains, of occasional cracking on moving
the joint, or of impairment of function--usually an inability to extend
or flex the joint completely. In many cases a clear account is given of
the symptoms which arise when the body is impacted between the articular
surfaces, namely, sudden onset of intense sickening pain, loss of power
in the limb and locking of the joint, followed by effusion and other
accompaniments of a severe sprain. On some particular movement, the
body is disengaged, the locking disappears, and recovery takes place.
Attacks of this kind may recur at irregular intervals, during a period
of many years. On examining the joint, it is usually found to contain
fluid, and there may be points of special tenderness corresponding to
the ligaments that have been overstretched. In cases in which there has
been recurrent attacks of locking, the ligaments become slack, the joint
is wobbly, and the quadriceps is wasted. The patient himself, or the
surgeon, may discover the loo