splaying
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Forefoot Splaying
 
Splaying of the forefoot is a condition where the intermetatarsal ligament is soft and loose, allowing the foot to spread.  In some cases the splaying can be a direct result of over pronation.  As the foot pronates and the longitudinal arch collapses, the transverse arch of the foot also will collapse.  Once this happens an the metatarsal heads are aligned and this causes them to spread to make room.  Now that all the metatarsal heads are on the ground, as the foot pushes off during gait, the stress of body weight and propulsion is put onto the metatarsal heads.  This will cause damage to the metatarsal heads and tendons associated with them.
See Metatarsalgia