A strain is an overstretching of a muscle, its fascial sheath, or a tendon. Most commonly, strains occur in larger muscles such as low back, calf and hamstrings.
A sprain, also known as a torn ligament, is damage to one or more ligaments in a joint. Sprains can occur in any joint but are most common in the ankle and wrist. The severity of sprain ranges from a minor injury which resolves in a few days to a major rupture of one or more ligaments requiring surgical fixation and a period of immobilization. Sprains are caused by trauma or the joint being taken beyond its functional range of motion.
Signs and symptoms are similar for both strains and sprains. They include pain, edema, decrease in range of motion and contusion.