way similar to that of the sesamoids and when fractured,
complete recovery is improbable in the average instance. When complete,
transverse fractures permit of separation of the parts of bone. Tension
on the straight ligaments below and contraction of the quadriceps above
usually cause insuperable difficulty in the handling of this type of
fracture in the horse.

Compound fractures as well as multiple or comminuted fractures
occasionally occur and these constitute injuries which are generally
considered fatal, although Andrien, according to Cadiot and Almy,
succeeded in obtaining complete recovery in a case of compound fracture
of the patella and the horse was in service and almost free from
lameness two months after treatment was begun.

No difficulty is encountered in recognizing the fracture of the patella
because of the exposed position of the bone. Crepitation, and in some
cases fissures, may be easily detected.

Treatment.--In simple fracture, when treatment is thought advisable,
the subject is put in a sling and kept as nearly comfortable as
possible. If little inflammation exists, the application of a vesicant
two or three weeks after the injury has been inflicted will be helpful
and serve to hasten repair.

Bandages or mechanical appliances are of no practical use in the
handling of these cases.

Luxation of the Patella.

Etiology and Occurrence.--This, the most common luxation met with in
the equine subject, has been described by writers as existing in many
forms. Patellar disarticulation may be more practically considered as
_momentary_ and _fixed_, regardless of the position taken by the
patella. Described under the title of false luxation are recorded cases
wherein the quadriceps (crural) muscles become contracted in such manner
that a condition simulating true disarticulation of the patella obtains.
Also, some practictioners report cases of patellar luxation and refer to
pseudo-luxations, without clearly defining the conditions which
constitute pseudo-luxation. This has contributed to the extant cause of
misconception as to actual differences between luxation and conditions
simulating dislocation.

Luxation of the patella is a condition wherein the articular portions of
the femur and patella assume abnormal relations whether such
displacement of the patella be momentary and capable of spontaneous
reduction, or fixed and requiring corrective manipulation. Spasmodic
contraction of the crural muscl