Also found in: Medical.
in anatomy and physiology, a fundamental principle of the distribution of motor and sensory fibers in the nerve roots of the spinal cord. The Bell-Magendie law was established in 1822 by the French physiologist F. Magendie. At its base lay, in part, the observations of the English anatomist and physiologist C. Bell, published in 1811. According to the Bell-Magendie law, efferent (motor) nerve fibers emerge from the spinal cord as part of the anterior roots, and the afferent (sensory) fibers enter the spinal cord as part of the posterior roots. The efferent nerve fibers that innervate the smooth muscles, blood vessels, and glands also emerge from the anterior roots.