What are the two broad categories of thermal agents?

What are the two broad categories of thermal agents?

• A. Internal and external
• B. Local and systemic
• C. Deep and superficial
• D. Primary and secondary

Answer: (C)

Thermal agents are categorized by how deeply they heat tissues. Superficial heating raises temperature in the skin and the layer just beneath it, useful for addressing surface structures and for increasing tissue extensibility or blood flow in nearby tissues. Deep heating, on the other hand, targets tissues farther below the surface—like muscles and joints—requiring modalities that penetrate deeper, such as ultrasound or diathermy. The other options don’t describe depth of heating and thus don’t fit as broad categories of thermal agents.

Thermal agents are categorized by how deeply they heat tissues. Superficial heating raises temperature in the skin and the layer just beneath it, useful for addressing surface structures and for increasing tissue extensibility or blood flow in nearby tissues. Deep heating, on the other hand, targets tissues farther below the surface—like muscles and joints—requiring modalities that penetrate deeper, such as ultrasound or diathermy. The other options don’t describe depth of heating and thus don’t fit as broad categories of thermal agents.