What does electromyography measure?

Electromyography measures the electrical activity of muscle fibers when they are activated. This technique involves placing electrodes on the skin over the muscle or inserting a fine needle electrode directly into the muscle. The resulting electrical signals from the muscle are captured and displayed as waveforms, allowing healthcare professionals to assess the muscle's health and function.

Understanding this activity is crucial in diagnosing conditions that affect muscle function, such as nerve damage, muscle disorders, and neuromuscular junction issues. The other options relate to different physiological measurements; for instance, heart rates are measured using an electrocardiogram, blood pressure is assessed using a sphygmomanometer, and joint mobility typically involves physical examination techniques measuring the range of motion. Each of these options tests different bodily functions that are unrelated to the muscle activity assessed by electromyography.