Fetlock, pastern and coffin joints of the hind leg are so closely allied to those of the fore leg that it is not worth while discriminating between them.
CHAPTER III.
MYOLOGY.
The branch of anatomy which treats of the muscular system is called Myology.
Muscles are the active organs of motion, or locomotion, each being separated from the other by a thin delicate membrane made up of connective tissue, which forms a sheath for the muscle. A muscle is divided into two parts, viz.: muscular and tendinous. The muscular part is the larger of the two. It is sometimes called the belly of the muscle or flesh. This part is known as muscular tissue, and has a reddish, meaty color. At both ends of the muscle there is a tendinous part, or the hard, white portion of the muscle which becomes attached to the bone. All muscles are attached to two or more places of different bones, and when contracted, the joints of the body are moved. They are well supplied with nerves, which give strength and feeling, and also well supplied with small blood vessels, from which the muscle is fed. Muscles are found in separate groups, all of which have different actions to perform. There are two kinds of muscles—voluntary and involuntary. The voluntary muscles are under the control of the will of the animal; example—the muscles of the head, neck, back, hip and legs. The involuntary muscles are beyond control of the animal, and will act even though the animal were asleep—such as those of the heart, the large muscular curtain which separates the chest cavity from the abdominal cavity, which is one of the great muscles of breathing; also the muscles around the chest which assist in breathing.
MUSCLES OF THE HORSE—SUPERFICIAL LAYER—AFTER MEGNIN.