Which of the following types of currents are included under High Frequency Currents?

High frequency currents refer to electrical currents with a frequency above the audible range, specifically those that are typically above 1 MHz. The inclusion of shortwave, microwave, and ultrasonic diathermy as high frequency currents is accurate because they all operate at frequencies that fall within the high frequency category and are commonly used in therapeutic applications.

Shortwave diathermy works by using radio frequency (RF) currents to produce heat in body tissues for pain relief and muscle relaxation. Microwave therapy also utilizes RF waves, producing deeper heating effects. Ultrasonic diathermy, on the other hand, uses high-frequency sound waves to create localized heat and promote healing in tissues. All three methods are effective modalities that leverage the benefits of high frequency currents in physical therapy and chiropractic settings, making this option the correct choice.

In contrast, direct current and alternating current don’t specifically fit in the high frequency category as they operate at lower frequencies. Low frequency modalities are used for different therapeutic purposes and are not classified under high frequency currents. Thus, options that mention frequencies outside the high frequency range do not align with the classification of currents defined by frequency in therapeutic contexts.