DISEASES OF THE BONES, JOINTS, AND TEETH 213 



Sprain of the fetlock joint results in momentary separation of 

 the joint surfaces and overstretching of the joint capsule and lig- 

 aments. The causes are traumatisms, like fast work on rough 

 ground and catching the foot between planks. When passively- 

 rotated pain is severe. Within a short time swelling, heat, and 

 lameness are noticeable. Treatment consists in rest and moist 

 heat. The application of a plaster-of-Paris bandage gives support 

 and at the same time compression, both of which hasten recovery. 



Deforming arthritis is seen in both young and old horses. Its 

 presence is shown by a deforming enlargement of the affected 

 joint. The causes may be infection through the navel while it is 

 yet raw; rheumatism; traumatisms. Lameness of a transitory 

 character that becomes gradually more persistent and permanent 

 is the first symptom. There soon develops a sensitive swelling 

 throughout the joint, and an effort is made to restrict joint move- 

 ment as much as possible. This may shortly result in a pecuhar 

 gait even when walking. Figure 61 is a photograph of one of the 

 author's cases. ^ It shows erosion of the articular cartilages, dis- 

 tention of the joint capsule, free joint bodies, and other degenera- 

 tive and proliferative changes. The probability of effecting a cure 

 in this class of joint troubles is very remote. 



Bog spavin is a serous inflammation of the sjnnovial layer of 

 the capsule of the hock-joint. It is accompanied with the forma- 

 tion of an abnormal amount of synovia which causes the soft tis- 

 sues around the joint to bulge outward. Horses of all ages are 

 subject to bog spavin, but it is more common in loose-jointed 

 draft colts. It rarely occasions lameness and may disappear 

 without treatment. The well-defined, puffy swelling is soft and 

 situated in front and to the inside of the hock (Fig. 62). Treat- 

 ment should aim at the absorption of the accumulated fluid. This 

 is best accomplished by applying a special bog-spavin truss, ar- 

 ranged so as to bring pressure over the swelling. Blisters afford 

 but httle relief in these cases. The fluid may be drawn off anti- 

 septically with a capillary trocar or aspirating syringe, but the sac 

 will fill again in a short time. Tincture of iodin, applied externally, 

 helps to absorb the fluid. Old cases do not respond to treatment 

 at all satisfactorily. 



Thoroughpin is found associated with bog spavin. If the latter 

 is not large, little or no evidence of a thoroughpin will be evident. 

 ' American Journal of Veterinary Medicine, vol. viii, May, 1913. 



