COMEDK 2007 MCQ Answer 87

The correct answer is B

The anterior spinal nerve roots contain only motor fibres and posterior roots only sensory fibres.

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 physiologie expérimentale et de pathologie, Magendie gave experimental proof of the Bell-Magendie law.

Magendie proved Bell’s law by severing the anterior and posterior roots of spinal nerves in a litter of puppies. Stimulation of the posterior roots caused pain.