A typical depth of penetration for thermotherapy is

• A. 0-0.5 cm
• B. 1-2 cm
• C. 3-5 cm
• D. 5-6 cm

Answer: (B)

Thermotherapy typically heats superficial tissues, with energy penetrating only a limited distance into the body. For common superficial heating methods, the warmth reaches about one to two centimeters beneath the skin. This depth effectively warms skin, subcutaneous tissue, and superficial muscle to help alleviate stiffness or spasm, without targeting deeper structures. Shallow ranges like 0-0.5 cm would mostly affect the surface and not produce meaningful therapeutic warming of deeper tissues, while deeper ranges such as 3-5 cm or 5-6 cm would require more powerful or different energy delivery and are not considered typical for standard thermotherapy. If deeper heating is needed, other modalities designed for deeper penetration would be used.