What is a primary indication for thermal ultrasound?

Thermal ultrasound is primarily indicated for its ability to create heat in tissues, which can lead to increased tissue extensibility and reduced muscle spasm. The application of heat facilitates the stretching of connective tissues, helping to improve mobility and flexibility. This is particularly beneficial when inflammation is not present, as it allows for better manipulation of the tissues without the risk of exacerbating any inflammatory conditions.

The process of using thermal ultrasound in this context involves using the heat generated to relax and elongate collagen fibers in tendons and ligaments, making them more pliable. This reduced stiffness can be crucial for rehabilitation in cases where the tissues are otherwise tight or limited in their range of motion.

Other options provided, while associated with ultrasound therapy, do not align as closely with the primary use of thermal ultrasound. For instance, while promoting blood flow and reducing pain are important therapeutic goals, they may not require the specific thermal effects of ultrasound or might serve different therapeutic modalities. In cases of active inflammation, the application of heat could potentially worsen the condition, thereby making it contraindicated.