Metatarsalgia
Nature
Metatarsalgia, literally metatarsal pain and colloquially known as a stone bruise, is any painful foot condition affecting the metatarsal region of the foot. This is a common problem that can affect the joints and bones of the metatarsals.
Metatarsalgia is most often localized to the first metatarsal head – the ball of the foot just behind the big toe. There are two small sesamoid bones under the first metatarsal head. The next most frequent site of metatarsal head pain is under the second metatarsal. This can be due to either too short a first metatarsal bone or to "hypermobility of the first ray" – metatarsal bone and medial cuneiform bone behind it – both of which result in excess pressure being transmitted into the second metatarsal head.
Source: Wikipedia
Type
(G) Very specific problems