Metatarsophalangeal joint sprain: An injury to the big toe due to forced hyperextension (bending back) of the toe. The damage is to the capsule of the first metatarsophalangeal joint and to the ligaments that connect the big toe to the foot. The big toe is painful, tender and swollen. Treatment is with icing, rest and anti-inflammatory medication. Taping of the big toe and a stiff insole insert in the shoe may help prevent recurrent hyperextension of the toe.
Shoes that are too flexible predispose to the injury. So do the artificial playing surfaces used today in American football and some other sports. This has led to the popular name for metatarsophalangeal joint sprain -- turf toe.