What is Hypermobility of the First Metatarsal Bone?
Hypermobility refers to the excessive motion present at the first metatarsal bone. In the normal foot, there would be very little motion at this area. But in a foot with hypermobility of the first metatarsal bone, there is an excessive amount of motion that takes place. According to Dr. Dudley J. Morton, the reason for the excessive motion is due to an abnormal laxity (looseness) of the plantar ligament that runs under the metatarsal bone. This laxity is normally inherited. Because the ligament is abnormally loose, the first metatarsal bone is not as stable as it should be, resulting in many foot problems. In a 1928 paper in the Journal of Bone & Joint Surgery Dr. Morton wrote that the hypermobility of the First Metatarsal Bone may not be as famous as the short first metatarsal bone, but it “is responsible for the widest range of foot problems.” How Important Is This? Hypermobility of the first metatarsal bone is the real cause of the granddaddy of all foot problems, “fallen arches.” A
