A foot sprain is a tear of ligaments, the tough bands of fibrous tissue that connect bones to one another inside a joint. Sprains range in severity from Grade I to Grade III.
Grade I — The injury is fairly mild, causing microscopic tears or stretching of the ligaments.
Grade II (moderate) — The ligaments may be partially torn, and the stretching is more severe.
Grade III (severe) — The ligaments are completely torn, so the foot may be unstable and no longer able to bear weight.
Because the foot bears the entire body's weight with each step and contains numerous bones and joints, you may expect the foot to be at high risk of sprains. However, sprains of the foot are fairly rare, except in people who participate in certain sports or occupations that subject the feet to abnormal twisting motions or bends.
When foot sprains occur, they usually involve one of two distinct areas:
Midfoot — The midfoot is the central area that includes the arch of the foot. In athletes, midfoot sprains usually occur because of a sports-related fall, a collision or an isolated twist of the midfoot, particularly during snowboarding, windsurfing, horseback riding or competitive diving. Among female ballet dancers, midfoot sprains typically happen when the dancer loses her balance while en pointe (on her toes) and spinning or when she lands with her foot abnormally flexed or rotated after a jump. Among people who do not compete in high-risk activities, about one-third of midfoot sprains happen by accident, simply because of an odd twist of the foot during an ordinary stumble or fall. Less often, severe midfoot sprains are the result of high-impact trauma, especially trauma caused by a motor vehicle collision or a fall from a high place. This type of injury is likely to produce not only Grade III sprains, but also foot fractures and open wounds.
First metatarsophalangeal joint — This is the joint at the base of the big toe. A sprain of this joint is called turf toe, and it is usually caused by hyperextension (extreme backward bending) of the big toe. The typical scenario involves either a football player or a ballet dancer who falls forward while the big toe is planted flat against the ground. In football, turf toe is most common in players who wear lightweight soccer-style shoes while competing on artificial playing surfaces. The relatively flexible soles of their shoes probably don't offer enough protection for the first metatarsophalangeal joint, increasing the risk of a turf toe injury. The situation is probably similar for ballet dancers, particularly males.