PTA Physical Therapy Assistant

Answer: B - Usually a cold- related injury occurs when a skin temperature is 55 degree F.

When the skin temperature is at 32 degree F, the intracellular fluids begin to freeze and results in frostbite.

When the skin temperature drops to 9 degree F, neurological changes begin to appear. Muscle spindles are activated.

When the skin temperature drops to 13.3 degree F, the motor nerve conduction velocity is reduced by 14%. Sensory nerve conduction velocity is reduced by 33%.