Differences in Temperature of Skin and Muscles of the Lower Extremities Following Various Procedures. ∗

During the past 2 years we have been investigating the regulation of the circulation in the muscles of the lower extremities. Variations in the temperature of tissues were accepted as indicating variations in the blood flow to those tissues. Thermocouples were used to determine skin surface temperatures, and the temperatures of the muscles were established by thermocouple needles inserted deep into these structures. Associated changes in body temperature were noted by means of a continuous registering rectal thermometer. In each experiment stabilization of skin, muscle, and room temperatures were obtained before any procedure was begun. Temperature observations were continued for a period of from 2 to 5 hours in each instance.

The application of heat to the upper extremities (Landis test) produced striking elevation in the surface temperature of the skin of the feet, but the muscle temperature of the legs remained unchanged. Paravertebral injections of novocaine were followed by a marked rise in skin surface temperature but no change occurred in the temperature of the muscles. Paravertebral injections of alcohol, which produce a more prolonged effect than novocaine, likewise failed to cause any elevation in calf muscle temperature although the skin surface temperature rose. Following spinal anesthesia the calf muscle temperature remained unchanged, while the temperature of the surface of the skin became markedly elevated. Intravenous injections of hypertonic sodium chloride solution were followed by elevation of both skin and muscle temperatures.