Introduction Electromyography (EMG) devices are considered important medical technologies in the field of Biomedical Engineering. They are used to record and analyze the electrical activity generated by muscle function, helping physicians evaluate the efficiency of the nervous and muscular systems and detect disorders that may affect their functions. Working Principle of the Device Electromyography devices operate by using electrodes placed on the surface of the skin or inserted into the muscle using fine needles to detect the electrical signals generated during muscle contraction. The device then amplifies, processes, and displays these signals in the form of waves and graphs, allowing the analysis of muscle activity and the identification of any abnormal changes. Medical Applications Electromyography is used in the diagnosis and monitoring of many neurological and muscular conditions, including: Neuropathies: Detecting peripheral nerve damage and disorders in nerve signal transmission. Muscle Weakness: Evaluating the electrical activity of muscles and identifying the causes of muscle weakness. Carpal Tunnel Syndrome: Assisting in the diagnosis of compression of the median nerve at the wrist. Neuromuscular Diseases: Contributing to the assessment of conditions such as Amyotrophic Lateral Sclerosis (ALS) and Myasthenia Gravis, depending on the type of examination. Nerve Injuries: Monitoring the effects of nerve injuries on muscle activity. Role of Biomedical Engineering Biomedical Engineering contributes to the development of electromyography devices by improving electrode design, developing digital signal processing techniques, reducing electrical interference, and increasing the accuracy of biological signal recordings. Modern technologies also allow these devices to be integrated with rehabilitation systems and intelligent prosthetic limbs. Conclusion Electromyography devices represent one of the important diagnostic tools that combine engineering and medicine. They provide accurate information about the electrical activity of muscles and nerves, helping detect neurological and muscular disorders and monitor their progression. With continuous technological advancements, these devices are becoming increasingly important in improving diagnostic accuracy and developing medical treatment and rehabilitation methods.