EXTREME LUXATION OF THE PATELLA IN A FOAL. 44 5 
be fully extended by the application of moderate force, while 
the two fore limbs tended to bend forward at the carpal joints, 
rendering difficult the maintenance of even the crouching po¬ 
sition mentioned for a sufficient period for the foal to suck. The 
hydrarthroses had extended far beyond the normal outline of the 
bnrs 3 e, especially outwards, extending over the external surfaces 
of the lower ends of femora and upper ends of tibiae, the definite 
outline of the bursae being lost externally and interiorly in the 
general swelling and thickening of the parts. The enlarge¬ 
ments were free from abnormal heat or tenderness. 
The patellae were displaced outwards and backwards and 
could be readily felt opposite the posterior border of external 
femoral condyles in immediate proximity to the posterior border 
of the tibiae at a distance from the heads of these bones corre¬ 
sponding to the tibial points of attachment of the tibio-patellar 
ligaments. 
The femoral trochleae appeared to be normal, but the patel¬ 
lae could not be replaced in them by ordinary manipulation. 
Bed sores were present on the anterior faces of the fetlock joints. 
The attitude of the foal when attempting to stand and the 
positions of the crural triceps group of muscles, especially the 
outlines of the rectus femoris and vastus externus and the loca¬ 
tion of the patella of left leg, are shown in Fig. i. The muscles 
of the posterior limbs appeared normal in size and form, but the 
extreme displacement of the patellae destroyed completely their 
power to extend the femoro-tibial articulations and to a great 
degree the extension of the coxo-femoral and tibio-tarsal joints. 
The foal was destroyed on July 3d by bleeding and the 
autopsy revealed the following abnormalties : 
The extensor pedis tendon of the left anterior limb was 
ruptured between its communication with the lateral extensor 
of the phalanges and the annular carpal ligament within the 
bursa through which it glides over the carpus, the muscular 
end of the tendon being indirectly adherent to the carpal liga¬ 
ment through its fibrous sheath, while the distal end was free 
in the bursa, haemorrhagic, smooth and enlarged. The direct or 
