The horse's skeleton is composed (among others) of so-called "short bones" as the vertebrae, the bones of the Carpus and Tarsus (knee and hock) and so-called long bones as those constituting the “radius” (see Chapter 14) canon bones (metacarpals) or even the ribs.
The evaluation of the skeleton in terms of "lightness" or "heaviness" is done regarding the ratio between the size and the section of the long bones.
The same exercise addressing short bones will determine if the horse is "weak" or "strong" at the level of the joints.
As there is no other way to measure the diameter of most of the long bones than the naked eyes, except for the canon bone, this is by comparing the diameter or the circumference of the canon bone in relation to the horse’s silhouette, that the observer will have the filling of a “heavy” or “light” horse.
We have no objective method of characterization to propose to the extent where the diameter of most of long bones is not significant to the naked eye, except those of the guns. It is so by comparing the diameter or circumference of the barrel from the silhouette of the horse that the observer will have the feeling of a horse "heavy" or "light" in the legs.
In the same way, it is by visually rating the size and shape of the knees, hocks and 4 fetlocks, the diameter of the canon bone and the silhouette of the horse that the observer will have an impression of lightness or strength.
The forms and measures of short and long bones play a role in the strength of the skeleton. The concept of lightness or strength, which is commonly used and that we have taken, is a little improper insofar as it is attributed by the human eye without taking account of bone density, the solidity of the anchor points of the ligaments between all these bones (short bones between themselves, the short with the long, and the long between themselves).
Fetlock and hocks with protruding relief joints will be pledges of more resistant attachment of ligaments and tendons. The strength of a skeleton appreciates by its ability over the time to allow athletic performance. It assesses, for the older performers, by the state of conservation of their joints at the end of their career.
The diameter of the long bones is related to the total weight of the horse and a “heavy” skeleton, giving an impression of solidity, will also request more energy to move it.
Effort fractures of long bones are extremely rare and there is no evidence that they are correlated with their diameter. Without any exaggeration in lightness, it will be preferred to avoid too heavy skeleton requiring additional efforts to move.
The joints must be proportionate to the rest of the skeleton. Large, well designed and protruding joints were once considered 'power points' but for one use other than jumping.
The strength of joints and skeleton remain desirable qualities; the volume of the joints and the diameter of long bones must be judged "visually", likely to enable performance. It is not certain that the maximum is the best, but until evidence to the contrary, i.e. until science complete our information on this subject, it remains an appreciated feature by buyers, therefore, important to take into consideration.