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.
Flat feet, also known as acquired flat foot disorder, result from your collapsed arch. When standing, the sole of your foot should not touch the ground completely. However, a fallen arch causes your foot to roll inwards and your entire sole comes close to touching the ground. Because your feet are the foundation for your body, flat feet can cause problems throughout your skeletal structure and can even bring your joints out of alignment.