The five metatarsals in the foot act as a unit to help with sharing the load of the body and move position to cope with uneven ground.
Injuries usually occur as a result of a direct blow onto the foot, a twisting injury or over-use.
These bones can be fractured through impact (eg: someone stamping on your foot), through twisting and over-use (stress fractures).
The middle metatarsals are usually injured as a result of this over-use.
In other words, it is caused by an ongoing process - and not one single occurrence. This is common with athletes or ballet dancers.
The first, second and fifth metatarsals are the most commonly injured in sport.
Recovery/Treatment:
The cure is rest. If the cause is over-use then treatment can vary hugely. Training habits, equipment used and athletic technique should all be investigated.
With a bone fracture the bone can often have a pin or screw inserted to speed up the recovery.
It all depends on the damage and which metatarsal bone is involved.
It is impossible to put a time scale on recovery from a stress injury.
After initial rest, the training techniques or body mechanics may need minor tweaking or a major haul to avoid a repeat injury.
With an impact fracture, after the plaster and protective boot is not needed (usually after 4-6 weeks), it will be a case of exercise and increasing weight-bearing activities.
Full return to action can be anything from another four weeks and upwards - depending on the extent of initial damage.