Reference of sensation at the spinal level.

After the spino-thalamic tract has been cut in man, loss of sensation of pain and temperature caudal to the lesion is to be expected. In a small proportion of patients, although analgesia-in the usual sense of the term-is present, painful or thermal stimuli applied to parts of the body caudal to the lesion arouse a sensation, which is felt, not at the place actually stimulated, but in a normally innervated part of the body. Thus, a pin applied to the analgesic left leg, for instance, may cause a sensation referred to the normally innervated right leg. This form of reference of sensation following the cutting of the spino-thalamic tract on one side of the cord was described by Ray and Wolff in 1945. A somewhat similar phenomenon had previously been described by Obersteiner in 1881, and named