SPRAINS. — A joint is said to be sprained when it is twisted violently so that its ligaments are either over stretched or partially torn, with or with out displacement of the osseous surfaces. Sprains of the wrists and ankle-joints are most common.
Symptoms. — The first symptom of sprain is a very severe, often sickening pain, which is rapidly followed by swell ing (most noticed in those parts where there is least pressure from ligaments and tendons) and inflammation of the joints and its investing tissues, which is often chronic and tedious. As the in flammatory symptoms subside, the joint becomes stiff, and, when moved, pain ap pears and persists for some time. In some cases rigidity and wasting of the limb follow the disappearance of the in flammatory symptoms. If the ankle or the knee is sprained, the patient cannot walk at all or at best only with a limping gait.
Diagnosis.—The diagnosis of sprain is usually easy. If in a hinge-joint a lateral ligament has been entirely torn across, the gap may usually be felt, and an increased mobility of the joint will be present. Touch will detect a lacera tion of a muscle or a fracture with or without separation of the fragments as through the malleolus or in the lower end of the radius. "Sprain-fracture" (fracture of a portion of the articular surface), as pointed out by Callendar, may occur in the ankle, and may not be detected by touch, thus explaining many cases of ankylosis of the ankle following an apparently simple sprain.
Etiology. — Sprains are usually pro duced by a sudden wrench or twist of the joint, and occur in the ankle as the result of a misstep or fall upon the foot, and in the wrist as a result of a fall upon the hand. They occur more commonly in young and middle-aged adults, in joints that have previously suffered similar in jury, in deformed limbs, and in subjects having underdeveloped muscles and re laxed ligaments, as in weak-ankled per sons.
Pathology.—A sprain may be so slight that its effect quickly subsides, or it may be associated with dislocation or fract ure or both. The line of displacement • usually passes through that part in which there is normally the least motion; so that in the hinge-joints it is lateral.
Through this unnatural movement the synovial membrane is unfolded upon one side and compressed on the other and is usually crushed and torn. The liga ments are at first slightly stretched, but, being quite inelastic, may give way, if sufficient force be exerted upon them, resulting in various degrees of injury, from the rupture of a few fibres to that of the entire ligament, to its detachment from the bone, a fracture or dislocation, or a rupture of distant muscles. The blood-vessels about the joint are lacer ated, and more or less extensive rhage into the joint-cavity, into the in terstices of the articular structures, and into the surrounding connective tissue occurs. When the haemorrhage into the joint-cavity is large, it indicates severe injury and increases the gravity of the case; the fullness resulting from such extravasation may appear within a very short time, but usually after a few hours, being then formed partly by the extrava sation, but principally by effusion into the joint-cavity and the structures about the joint. After several days discolora tion of the skin is noticed, which is caused by subcutaneous capillary extra v asation. When the haemorrhage into the joint-cavity has been large. blood-clots often persist for some time. and, by be coming organized and adherent to the synovial membrane, result in the forma tion of adhesions which limit the move ments of the joint; if they do not, in deed, cause ankylosis.
Prognosis.—The prognosis varies with the joint involved, the extent of the injury, the habit of the patient, the promptness of attention, and the effi ciency of the treatment. When haemor rhage into the joint-cavity has been large, there is more interference with the action of the joint. In persons of gouty or rheumatic habit the inflammation of the joint is generally tedious and chronic , in character, and will only yield to suit- , able constitutional treatment (colchi cum, iodides. etc.). In strumous subjects destructive disease of the joint often follows this injury.