What is the difference between a sprain and a strain?
A sprain is an acute traumatic injury to a ligament. There are three grades of sprains:
- • First-degree—mild pain due to tearing less than one-third of ligamentous fibers, <5 mm laxity.
- • Second-degree—moderate pain and swelling, one-third to two-thirds of fibers of ligament torn, 5 to 10 mm laxity.
- • Third-degree—severe pain from a complete rupture of the ligament causing joint instability.
A strain is an acute traumatic injury to the muscle–tendon junction. It is commonly called a “pull.” Strains are also classified according to three grades:
- • First-degree—mild.
- • Second-degree—moderate injury associated with a weak and painful contraction of the involved muscle.
- • Third-degree—complete tear of the muscle–tendon junction resulting in severe pain and an inability to contract the involved muscle.