The inside of the ears and the muzzle are black, and the feet are black to the fetlock joint.
In colour the sides of the face are puce, and the neck and most of the body purplish, but the buttocks and upper part of both fore and hind limbs are transversely barred with black and white, while their lower portion is mainly white with black fetlock-rings, and in the front pair a vertical black stripe on the anterior surface.
This is called in veterinary anatomy the " suspensory ligament of the sesamoids," or of the " fetlock " (io in fig.
The carpal joint, corresponding to the wrist of man, is commonly called the " knee " of the horse, the joint between the metacarpal and the first phalanx the " fetlock," that between the first and second phalanges the " pastern," and that between the second and third phalanges the " coffin joint."
The withers may be moderately high and thin; the chest well developed, but not too wide or deep; the shoulder should lie well on the chest, and be oblique and well covered with muscle, so as to reduce concussion in galloping; the upper and lower arms should be long and muscular; the knees broad and strong; legs short, flat and broad; fetlock joints large; pasterns strong and of moderate length; the feet should be moderately large, with the heels open and frogs sound - with no signs of contraction.
The hackney should also possess good hock action, as distinguished from mere fetlock action, the propelling power depending upon the efficiency of the former.
A white fetlock-gland with a black centre is also distinctive of this species.