A sprain occurs when one or more ligaments have been stretched, twisted or torn, usually as a result of excessive force being applied to a joint. Ligaments are strong bands of tissue around joints that connect bones to one another.

There may be swelling soon after the injury but the bruising may not show until later or it may not show at all.

Bruising sometimes develops away from the affected joint, as blood seeps along the muscles before surfacing to the skin.