CAPPED HOCK. 
745 
(8) Of a swelling originating in the flexor pedis perforatus at the point 
where the latter covers the point of the hock, forming a cap. 
(4) Of hydrops of the bursa tendinea of this tendon; or, finally, 
(5) Of thickening of the point of the hock, due to disease of the tendon 
of the flexor pedis perforates. 
Causes. Capped hock results from external injuries produced by kicks 
or striking against hard objects, from slips, violent exertion, and occa¬ 
sionally as a sequel to purpura htemorrhagica. Confirmed kickers and 
irritable mares often have both hocks capped 
—an indication which it is well to note when 
handling such animals. The horses often 
strike themselves against the side of the truck 
or vessel when travelling by rail or water, and 
produce capped hock. At one time it was 
thought that in mares the condition was pro¬ 
duced by the urine. 
Symptoms. Though the swelling is recog¬ 
nised at a glance, especially if the hock be 
seen from the side, yet careful examination 
and palpation are required to determine the 
exact cause to which it is due. (Edema and 
inflammation of the skin are easily detected. 
Hygroma of the bursa subcutanea has an 
elastic character, and the swelling lies just 
under the skin, while hydrops of the tendon 
sheath is deeper seated, and is covered by 
the flexor pedis perforatus. Swelling of the 
tendon itself is characterised by greater hard¬ 
ness—a feature still more marked in exostoses 
on the tuber calcanei. 
In acute inflammation, increased warmth 
and pain can be detected. Purulent cellulitis 
and disease of the bursa subcutanea may lead to well-marked and widely- 
distributed swelling; the tumour on the point of the hock is then rounded 
in shape, and may attain the size of a child’s head. In aseptic inflam¬ 
mation, on the contrary, swelling is confined to the original spot. 
Lameness is rarely marked, and never occurs in simple injury of the 
skin or mucous bursa. Even when purulent inflammation sets in, it 
seldom produces lameness. On the other hand, inflammation of the 
flexor pedis perforatus, of its tendon sheath, or of the tuberosity of the 
os calcis, may produce great difficulty in movement; infectious conditions 
in these structures are generally accompanied by severe lameness; but in all 
aseptic processes lameness is absent, or only occurs during development. 
Fig. 276.—Capped hock. (dropsy 
of the subcutaneous bursa of 
the hock). 
