Myelitis, inflammation of the spinal marrow (Greek myelos, "marrow"), is a disease which sometimes results from exposure to cold, and may supervene upon caries of the vertebra, the spinal cord from its position in the spinal canal being particularly liable to involvement in cases of vertebral disease. The symptoms vary according to the part of the spinal cord which is affected. Both sensation and power of movement are, as a rule, implicated, and these symptoms are generally especially manifested in the lower limbs, producing paraplegia (q.v.), though the arms may be also attacked; when one side of the spinal cord is especially involved, the symptoms are particularly developed on one side of the body. Pain is not usually a marked symptom; there is rather loss of sensibility as a rule; there may be, however, a feeling of constriction as of a band drawn tightly round the body in the situation corresponding to the superior limit of the portion of spinal cord which is affected. Bedsores are apt to develop, and trouble in connection with the bladder not infrequently arises. Acute myelitis is a serious disease, which frequently terminates fatally. In the milder form of the malady recovery may occur, but some degree of paralysis is usually left behind.