Fic. VILI.— Femoro-patellar articulation (gonitis), from Case IV. S. M., Synovial membrane, 
thickened and tufted. N, Calcified nodule in the walls of the articular capsule, from which sus- 
pended by a narrow neck, 1s a second nodule, N’, which might readily become a floating body. E. 
C, Diminutive and flattened external femoral condyle, between which and the enlarged internal 
condyle, I. C., the trochlear groove is practically wanting. P, Patella, showing at E, an extensive 
erosion, caused by friction in passing out and in over E. C, at E’, the result of ‘‘ floating disloca- 
tion of the patella.”’ 
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Fic. IX. — Gonitis and floating luxation of the patella in eighteen-months colt. . 
I. Normal femur. II. Diseased femur from Case IV, showing another view of the femur ir 
Fig. VIII. 
A, External condyle. B, Internal condyle. ai 
In I, the external condyle is sharply defined and well elevated above the sulcus, while in II the 
condyle is rotund, flattened with almost no depression or groove between it and the internal condyle. 
The differences between the two internal condyles is very much greater. The normal (I) is well- 
defined and sharp, while the diseased (II) is greatly enlarged, puffed up, and undulating at its 
upper part. There is in JI no trochlear groove in which the patella may glide, and no external 
trochlear ridge to guide it; hence patella slipped out and in position at each step. 
