An EMG (Electromyography) and Nerve Conduction Study (NCS) are combined diagnostic tests that evaluate the health of your muscles and the nerves controlling them, identifying problems like nerve damage (neuropathies, carpal tunnel) or muscle disorders (muscular dystrophy, ALS) by measuring electrical signals in muscles (EMG) and how fast signals travel along nerves (NCS). The NCS part uses surface electrodes to stimulate nerves, while the needle EMG involves inserting a fine needle directly into muscles to record electrical activity at rest and during contraction, revealing nerve or muscle disease.