Demyelinating disease. A demyelinating disease is any disease of the nervous system in which the myelin sheath of neurons is damaged. This damage impairs the conduction of signals in the affected nerves. In turn, the reduction in conduction ability causes deficiency in sensation, movement, cognition, or other functions depending on which nerves are involved.
For other uses, see Reamer (disambiguation). A reamer is a type of rotary cutting tool used in metalworking. Precision reamers are designed to enlarge the size of a previously formed hole by a small amount but with a high degree of accuracy to leave smooth sides.
Orthodontic spacer. Orthodontic separators (commonly known as spacers) are rubber bands or metal appliances used in orthodontics. Spacers are placed between the molars at the second orthodontic appointment, before molar bands are applied. Spacers are either circular rubber bands about a centimeter in diameter placed between top and bottom molars; there may be 1-12 spacers applied or small metal spring clips (spring separators) that push the molars apart.