CHAPTER III

PROPORTIONS AND MECHANICS OF THE

HORSE

By proportions of the horse are meant the correlation and the agreement of the various parts with each other and with the body as a whole. The parts of the horse when studied in the light of proportions show us relations of length, width, thickness, direction, development and the like. This detailed study of the relationship of the various parts is very efficient in developing the "eye" and the judgment.

The proportions of the horse are considered from two points of view. First, the relations existing between the length, width and thickness of the various parts of the horse; and second, the relations of the directions possessed by the bones superposed one upon the other, thus forming angles. These relations tend to make the legs long or short and have an influence upon the production of speed or power.

Dimensions of the parts.-To study the relation existing between the various parts of the horse, we must first obtain the dimensions of the parts. The lengths, widths, thicknesses, and the like, are taken with a measuring! staff of parallel bars, the circumference with a tape and the angles and inclinations with a compass and plumb line, although for accurate results in measuring the angles an arthrogoniometer should be used. This is an instrument somewhat similar to a compass. The following list includes the more important parts useful in a study of the proportions of the horse:

Measurements of horse.-Accurate measurements are stremely difficult to obtain: First, because the horse is ›ntinually shifting his position, which alters the meas

urement; and, second, because some of the parts are not well defined and it is often difficult to know just where to begin the measurement. Where reliable information

is desired, the measurements should be carefully checked. The following table gives an idea of the measurements of some of the more important parts in both heavy and light horses:

MEASUREMENTS FOR DRAFT AND SPEED HORSES

The unit of proportions. In a study of the proportions of the horse, the length of the head is taken as the unit. This is because the head varies less, perhaps, than any other part and its length is easily obtained, as the boundaries are clearly defined. It is interesting to note that the total height of the horse from the crest of head to the ground is equal to about three head lengths; that the height from the withers and from the croup to the ground,

as well as the total length of the horse from the point of the shoulders to the buttocks, is about 22 head lengths; and that the length of the neck from poll to withers, the length of the shoulder from the withers to the point at the elbow, the thickness of the body from side to side, and the depth of the body from back to the abdomen, is equal to about one head length.

Dimensions of articular angles.-Besides the relations

of length, width and thickness which exists between the different parts of the body, it is also important to know the relations of directions possessed by the different bony regions, superposed one upon the other, to form the fore and hindquarters. From the manner in which the bones are arranged angles are produced. The inclination of the bones and the dimensions of the angles have an influence upon the draft and speed. Such measurements as these, however, are exceedingly difficult to obtain, as the bones are so deeply imbedded in muscle that their direction cannot be located with exactness. The following table includes the more important parts useful in a study of the proportions of the horse.

STUDENT'S CARD FOR THE ARTICULAR ANGLES OF THE HORSE.

Scapular*.

Humeral..

Iliac.

Femoral...

Tibial.

INCLINATION UPON THE HORIZON

ARTICULAR ANGLES IN STATION

Scapular-humeral.

Humero-radial.....

Metacarpo-phalangal..

Ilio-femoral

Femoro-tibial.

Tibio-metatarsal.

Metatarso-phalangal..

ATTITUDES IN STATION

Anterior members viewed in profile.

Anterior members viewed in front..

Posterior members viewed in profile....

Posterior members viewed from behind.

*For location of parts see page 35.

Degrees Degrees