March fractures are a subtype of fatigue/stress fractures. They occur due to repeated concentrated trauma to a normal bone, classically the 2metatarsal of the foot but can occur in other weight-bearing bones of the lower limb and pelvis.
Please see the article on stress fractures.
History and etymology
The name arises from its prevalence in soldiers who often undertake repeated and lengthy periods of marching as part of training or work .