1. The sensibility of a joint is primarily a periarticular sensibility, due to the abundance of nerve endings in the joint capsules and periarticular ligaments.
2. In sprains, pain is due primarily to trauma of the periarticular innervation. Reflex muscular rigidity, involving the injured joint, also has its origin in the traumatized nerves of the joint capsule and ligaments.
3. Periarticular injections of novocain have a definite therapeutic value in the treatment of sprains. The pain and reflex muscular rigidity abolished, almost normal function is possible. In some instances the improvement is more or less permanent; in other cases several injections are necessary.