Thermotherapy can be applied as superficial or deep.

• A. Superficial only
• B. Deep only
• C. Superficial or deep
• D. It depends on device

Answer: (C)

Thermotherapy can target different tissue depths depending on how it is delivered. Conduction-based methods like hot packs or moist heat heat chiefly the superficial layers—the skin and just beneath it—while modalities that transmit energy into the body, such as ultrasound or diathermy, can reach deeper structures like muscle and joint tissues. The depth of heating is governed by the modality’s physics (frequency, wavelength, intensity) and the application time, so the same idea can be applied to either superficial or deep tissues. That’s why the best answer is that thermotherapy can be superficial or deep.