Motor nerves are bundles of nerve cells that control muscles. They originate in the spinal column and end at the muscles that they control. One motor nerve often controls several muscles.
There are three types of motor nerves. Somatic motor nerves control skeletal muscles, which cause movement. Special visceral motor nerves control muscles in the face and neck. General visceral motor nerves control the smooth muscles that lack voluntary control, such as the heart. Another term for a motor nerve is "motor neuron." Motor nerves work by sending chemicals, known as neurotransmitters, across a gap between the nerve and the muscle. The neurotransmitters bind to receptors in the muscle fiber and trigger movement.