FRACTURES.—Broken bones or fractures are not uncommon in domestic animals. In the horse, the bones of the leg, forearm, foot, and spine are the most commonly broken. In the dog the largest percentage of fractures occurs in the superior regions of the limbs.

Fractures may be classified as simple and compound, complete and incomplete, comminuted or splinter. In the simple fracture the skin over the region escapes injury, but in the compound fracture the skin is broken and the ends of the broken bone may protrude through it. The terms complete and incomplete are used in describing fractures in which the ends of the bones are not attached to each other, or partially so. In the comminuted fracture the bone is broken into a number of pieces. There are a number of other terms that may be used in designating the different kinds of fractures, such as double, when both bones in the region are broken, and oblique, transverse and longitudinal, depending on the direction of the break.

The causes of fractures may be divided into external or mechanical, and internal. Fractures may result from kicks, blows, muscular strain and contusions. Abnormal fragility due to disease, extreme youth and old age are the internal predisposing factors.

The symptoms are crepitation, abnormal movement and deformity of the part. Abnormal movement of the part and inability to support weight occur in fractures of the bones of the limbs. Crepitation or a grinding, rubbing sound due to the movement of the ends of the broken bones on one another occurs when the part is moved or manipulated with the hands. Pain, swelling and injury to the skin are other local symptoms. The new tissue or bone callus is formed by the bone-forming cells in the deeper layer of the periosteum and bone-marrow.

The prognosis is unfavorable. The larger percentage of fractures in domestic animals are incurable, or make an unsatisfactory recovery. This is due to careless treatment, the character of the fracture and the inability to fix the ends of the broken bone. Fractures in young and small animals usually heal quickly. Individuals that are healthy and vigorous usually make a speedy recovery. Fractures heal very slowly in the aged. Compound and comminuted fractures are impossible to treat in the larger percentage of cases.

The treatment consists in fixing the broken bone or bones in a normal position by means of bandages and splints. If this is not practised, the surrounding tissues become injured by the broken ends of the bone, and the fracture may become so complicated as to render treatment useless. Motion retards or prevents the repair of the break.

However, fractures of the ribs, pelvic bones and sometimes long bones that are well covered by heavy muscles heal naturally or in the absence of any means of retention.

Bandaging.—The attendant must use good judgment in devising means of fixing the broken bone, and in holding it in its natural position. Whenever possible, a plaster bandage should be used. This must not be made too heavy, and it is very necessary to adjust it properly, so that it will stay in place and not become too tight or too loose. When applied to the limb, the bandage should extend as far down as the hoof, and some distance above the break. This is necessary in order to keep it from slipping down and becoming too loose. A soft bandage should be applied first in order to equalize the pressure from the plaster cast and protect the skin. Wooden splints are not very satisfactory agents for the treatment of fractures. Thick leather that has been made soft by soaking in warm water and then shaping it to the part makes a more satisfactory splint. In all cases a soft bandage should be applied under the splint. The adjustment of the plaster bandage or splint should be noticed daily, and whenever necessary it should be removed and readjusted. Injuries to the skin must be carefully cleaned, disinfected and bandaged before applying the plaster bandage. If evidence of wound infection occurs later, the bandage must be removed and the wound treated. Large animals suffering with a fracture of any of the bones of the limb should be placed in slings. Incomplete fracture should receive the same treatment as simple fracture. If this is practised, the danger of its becoming complete is avoided.

[Illustration: FIG. 61.—Shoulder abscess caused by loose-fitting harness.]

HARNESS INJURIES.—This class of injuries is common in horses that are given steady, hard work, or that are not accustomed to work. Young horses, when first put to hard work, are especially prone to injuries from the collar. A large proportion of these injuries are due to an ill-fitting harness or saddle.

When the harness is not adjusted or fitted properly, there is severe pressure on certain parts. This is the common cause of shoulder abscesses (Fig. 61), sore necks and sit-fasts. Rough, uneven surfaces on the faces of the collar and saddle are the common causes of galling. The character of the work is an important factor. Work that requires the animal to support weight on the top surface of the neck is productive of sore neck. Heavy work over rough, uneven ground frequently causes shoulder abscesses and strained muscles.

The simplest and most common harness injuries are galling, sore shoulders and sore neck. Harness galls first appear as flat, painful swellings. On raising the collar from the skin the inflamed area appears dry and the surrounding hair is wet with sweat. Later, the skin becomes hard and its outer layer, and sometimes the deeper layer as well, slough, or is rubbed off by friction of the harness. The surface then appears red and moist. Fluctuating swellings due to small collections of blood and lymph sometimes form. Sometimes, small areas on the face of the shoulder and that portion of the back pressed on by the saddle become swollen, indurated and hard and give the shoulder a rough appearance. Continuous irritation from the collar may cause an inflammatory thickening of the subcutaneous tissue in the shoulder region, and the skin appears loose and somewhat folded. This uneven surface is productive of chronic collar galls.

A sit-fast is characterized by a large swelling at the top of the neck, followed by a deep sloughing of the tissues. A slightly swollen, wrinkled condition of the skin over the top of the neck is sometimes present in horses that resist the attendant, when he attempts to handle the part or harness the animal. This form of sore neck is evidently very painful, although little evidence of inflammation is present.

Strain of shoulder muscles and shoulder abscesses have been discussed under their separate heads.

The treatment is very largely preventive. Too little attention is given to the proper fitting of the harness and saddle. A well-fitted collar that properly distributes the weight on the shoulder, and is neither too small or too large at the top of the neck, is the best preventive for shoulder and neck injuries. Old, ill-fitting, lumpy collars should not be used. Neither should the same collar be used for different horses. Farmers should avoid using sweat pads that are lumpy or soaked with sweat. If soft and dry, such pads are useful in preventing galling. The surfaces of the collar or saddle that come in contact with the skin should be kept smooth and clean. In the spring of the year, it is advisable to bathe the shoulders of work horses with cold water twice a day. Bathing the shoulders with the following preparation is a useful preventive measure: lead acetate four ounces, zinc sulfate three ounces and water one gallon. Smooth leather pads for the top of the collar and saddle are useful preventive and curative agents.

Galls are lest treated by rest. Ointments or "gall cures" are usually applied. The following dry dressing dusted over the red, moist, abraded surfaces is quite healing: tannic acid one ounce, boric acid four ounces, and calomel two ounces. This may be dusted over the part two or three times daily. Dry, abraded surfaces may be treated by applying a mixture of glycerine four ounces, tannic acid one-half ounce and carbolic acid one dram. In operating for the removal of fibrous enlargements, thickened skin and abscesses on the front of the shoulder, it is advisable to make the incision in the skin well to the side of the face of the shoulder in order to avoid scarring the surface that comes in contact with the collar.

QUESTIONS

1. Name and describe the different kinds of fractures.

2. What are the symptoms of fracture?

3. Describe the treatment of fractures.

4. What are the causes of harness injuries?

5. Describe the treatment of the different harness injuries.