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.
Flexible flat feet generally do not require any treatment at all. Special shoes, shoe inserts and exercises do not lead to flat foot correction. For children younger than eight, physicians tend to recommend observation only. Doctors may recommend orthotics (shoe inserts) for middle- or high school-aged children with pain which seems to be due to flat feet.