formed and that these interfere with the recovery of
function. The condition may be overcome by graduated movements or by a
sudden forcible movement under an anaesthetic. These cases afford a
fruitful field for the bone-setter.

#Rupture of Muscle or Tendon.#--A muscle or a tendon may be ruptured in
its continuity or torn from its attachment to bone. The site of rupture
in individual muscles is remarkably constant, and is usually at the
junction of the muscular and tendinous portions. When rupture takes
place through the belly of a muscle, the ends retract, the amount of
retraction depending on the length of the muscle, and the extent of its
attachment to adjacent aponeurosis or bone. The biceps in the arm, and
the sartorius in the thigh, furnish examples of muscles in which the
separation between the ends may be considerable.

The gap in the muscle becomes filled with blood, and this in time is
replaced by connective tissue, which forms a bond of union between the
ends. When the space is considerable the connecting medium consists of
fibrous tissue, but when the ends are in contact it contains a number of
newly formed muscle fibres. In the process of repair, one or both ends
of the muscle or tendon may become fixed by adhesions to adjacent
structures, and if the distal portion of a muscle is deprived of its
nerve supply it may undergo degeneration and so have its function
impaired.

Rupture of a muscle or tendon is usually the result of a sudden, and
often involuntary, movement. As examples may be cited the rupture of
the quadriceps extensor in attempting to regain the balance when falling
backwards; of the gastrocnemius, plantaris, or tendo-calcaneus in
jumping or dancing; of the adductors of the thigh in gripping a horse
when it swerves--"rider's sprain"; of the abdominal muscles in vomiting,
and of the biceps in sudden movements of the arm. Sometimes the effort
is one that would scarcely be thought likely to rupture a muscle, as in
the case recorded by Pagenstecher, where a professional athlete, while
sitting at table, ruptured his biceps in a sudden effort to catch a
falling glass. It would appear that the rupture is brought about not so
much by the contraction of the muscle concerned, as by the contraction
of the antagonistic muscles taking place before that of the muscle which
undergoes rupture is completed. The violent muscular contractions of
epilepsy, tetanus, or delirium rarely cause rupture.

The _clini