Which of the following is NOT a type of superficial heat?

• A. Hot packs
• B. Paraffin wax
• C. Ultrasound
• D. Fluidotherapy

Answer: (C)

Superficial heat modalities raise temperature mainly in the skin and just beneath it, using conduction or convection to warm the surface. Hot packs and paraffin wax contact the skin directly, transferring heat to superficial layers. Fluidotherapy delivers heat through warm air and suspended particles, affecting the superficial tissues of the area treated. Ultrasound, on the other hand, uses high-frequency sound waves that are absorbed by deeper tissues and converted to heat within those tissues; its depth of heating can reach muscle and other deeper structures, making it a deep heating modality rather than a superficial one.