Sprains are partial tears to a ligament( a strong band of connective tissue that connects the bones) around a joint.
Ankle Sprains are caused when the ankle rolls over out of the range of motion. There are three grades of sprains, the bigger the tear the higher the grade.
Wrist sprains are caused by a fall onto an outstretched hand. The severeness ranges from mild to severe( Grade 1-3). A mild sprain consists of a stretched ligament but not torn ( Grade 1). A grade 2 sprain is when the ligaments are partially torn. A severe sprain is a completely torn ligament (Grade 3). Severe sprains need medical attention.
Finger sprains occur when a finger is bent in a way that damages the ligaments. Hypertension can also cause a finger sprain. Finger sprains are common in sports with a ball.
Knee sprains are caused by sudden turns. As well as direct hits to the knee caused by falling or running into another player.