The principle in which the anterior spinal nerve roots contain only motor fibres and posterior roots only sensory fibres; nerve impulses are conducted in one direction is known as

(B) Bell-Megendie's Law # Bell-Megendie's Law: Anterior spinal nerve roots contain only motor fibres and posterior roots only sensory fibres and that nerve inpulses are conducted in only one direction.> Charles Bell's work of 1811 Contains the first reference to experimental work on the motor functions the ventral spinal nerve without, however, establishing the sensory functions of the dorsal roots.> In 1822 Magendie definitively discovered that the anterior root is motor and that the dorsal root is sensory. Magendie announced that "section of the dorsal root abolishes sensation, section of ventral roots abolishes motor activity, and section of both roots abolishes both sensation and motor activity". This discovery has been called "the most momentous single discovery in physiology after Harvey". In the same volume of Journal de physiologic experimental et de pathology, Magendie gave experimental proof of the Bell-Magendie law.