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.
Symptoms of flat feet and fallen arches. Many people have flat feet-and notice no problems and require no treatment. However, others may experience the following symptoms: 1  Feet tire easily. 2  Painful or achy feet, especially in the areas of the arches and heels. 3  The inside bottom of your feet becomes swollen.