_The causes_ of this unsoundness are hereditary and accidental. Weak knees due to faulty conformation seldom escape becoming sprung in animals that are given hard work. Severe and continuous driving is a common factor in the production of this condition. Strains of the flexor muscles of the region may cause it. The retraction of the flexor muscles and their tendons and the aponeurosis of the antibrachial region occurs in this disorder and prevents the animal from extending the knee. The region is greatly weakened by this condition and the animal may be unfitted for active work. For this reason the value of the animal is greatly diminished. _Treatment_ is unsatisfactory. The preventive treatment consists in not breeding animals that have poorly conformed knees and using the proper judgment in working young horses and when driving or riding horses. Certain cases may be greatly benefited by sectioning the tendons of the external and middle flexors of the metacarpi. To insure a successful outcome in any case that is operated on, a long period of rest is required. [Illustration: FIG. 33.--Sprung knees.] [Illustration: FIG. 34.--Splints.] SPLINTS.--A splint is a bony enlargement situated along the line of articulation between the splint and cannon bones (Fig. 34). This blemish is due to an inflammation of the periosteum. It is a very common blemish and is generally located along the splint bones of the forefeet, especially the internal ones. _Splints are caused_ by strains and rupture of the ligament that binds the splint bone to the cannon bone. The result is an inflammation of the periosteum. Slipping, or an unbalanced condition of the foot, may cause this injury by distributing the weight unequally on the splint bones. Faulty action and bad shoeing may cause the horse to strike and bruise the region. _Symptoms of lameness_ are not always present. A high splint involving the articulation between the lower row of carpal, splint and cannon bones may be considered an unsoundness, because of the persistent character of the lameness. The animal may show little or no lameness when walked, but if moved at a trot, especially over a hard roadway, it may show marked lameness. The local inflammation is characterized by a small swelling lying along the splint bone, that feels hot and may pit on pressure. After a time the inflammation disappears and is replaced by a hard, bony enlargement. When this occurs the lameness disappears. _The preventive treatment_ consists in keeping the feet of young horses in proper balance by frequent trimming and proper shoeing. This attention is very necessary in young colts that are running in pasture. It is very advisable to rest the animal during the period of inflammation. Cold bandages should be applied. As soon as the inflammation has subsided mild counterirritants and absorbents may be used. In. case the lameness persists, more severe counterirritation is indicated.