termed {perone}, being of the brooch-pin order.

If the young horse in walking bends his knees flexibly, you may safely
conjecture that when he comes to be ridden he will have flexible legs,
since the quality of suppleness invariably increases with age.[15]
Supple knees are highly esteemed and with good reason, rendering as
they do the horse less liable to stumble or break down from fatigue
than those of stiffer build.

[15] Lit. "all horses bend their legs more flexibly as time advances."

Coming to the thighs below the shoulder-blades,[16] or arms, these if
thick and muscular present a stronger and handsomer appearance, just
as in the case of a human being. Again, a comparatively broad chest is
better alike for strength and beauty, and better adapted to carry the
legs well asunder, so that they will not overlap and interfere with
one another. Again, the neck should not be set on dropping forward
from the chest, like a boar's, but, like that of a game-cock rather,
it should shoot upwards to the crest, and be slack[17] along the
curvature; whilst the head should be bony and the jawbone small. In
this way the neck will be well in front of the rider, and the eye will
command what lies before the horse's feet. A horse, moreover, of this
build, however spirited, will be least capable of overmastering the
rider,[18] since it is not by arching but by stretching out his neck
and head that a horse endeavours to assert his power.[19]

[16] Lit. "the thighs below the shoulder-blades" are distinguished
from "the thighs below the tail." They correspond respectively to
our "arms" (i.e. forearms) and "gaskins," and anatomically
speaking = the radius (os brachii) and the tibia.