Sprains and strains include laceration, rupture or tear of muscles, ligaments (which connect bones) or cartilage (which lines many joints). Most joints can suffer strain, including: the shoulder (scapula), the elbow (radius and ulna), the wrist (carpometacarpal joint), fingers, hip, knee, ankle, foot, neck, back, lumbosacral joint, jaw, pelvis, sternum and ribs.
A sprain is specifically a stretching or tearing of the elastic ligaments that connect bones. Studies show up to 40 percent of sprained ankles lead to recurring sprains, unstable joints, arthritis-like pain or other complications.
US orthopaedists estimate that 27,000 Americans a day sprain an ankle. It is the top orthopaedic complaint and most common sports injury.