Nerve fiber = multicellular, containing both an axon and surrounding myelin sheath. The axon comes from a single neuron, but the myelin sheath is made by a train of many myelinating Schwann cells. In the case of unmyelinated axons, the unmyelinated fiber shares each Schwann cell with several other unmyelinated axons.
Flat feet (pes planus) occur when a child has no arch in their foot. Because an arch does not form, the foot appears to turn to the outside. Children with out-toeing due to flatfeet will rarely experience pain symptoms will not require treatment.
These hip muscles control the alignment of the leg, and this determines how weight is transferred from the hip to the foot. If the line of force points down toward the inside of the foot instead of over the center then the joints of the foot and ankle are under pressure to roll inward. This is how hip weakness contributes to flat feet. Hip Muscles