Hand, foot, and mouth disease can occur in pre-kindergartens.
  The neural machinery underlying hand movements is a major contributing factor; primates have evolved direct connections between neurons in cortical motor areas and spinal motoneurons, giving the cerebral cortex monosynaptic control over the motoneurons of the hand muscles; placing the hands "closer" to the brain
 This is the commonest carpal bone fracture and can be slow to heal due to a limited blood flow to the bone

