A course in dissecting and the diffferent branches of medicine will not furnish the principles of chiropractic, reason out its philosophy, nor educate one in vertebral adjusting. Bones give rigidity and shape to the body, form a case around the brain and spinal cord, protect delicate organs in the body cavities, constitute a frame-work of which individual bones are used as levers by muscles and nerves. In many invertebrate animals the muscles are attached to the exoskeleton. In man they are connected to the endoskeleton. Nearly half of the body weight is of muscle.
Movements are performed by means of muscles, leverage is obtained by their attachment to bones.
Displaced bones cause muscles and nerves to become stretched or relaxed. Traumatism is a diseased condition of the system due to an injury or a wound. Luxated joints, more especially those of the vertebral column, cause traumatism, a diseased condition. Poisons affect nerves, cause their relaxation or contraction. Loss of tension produces atony, enervation, a diminution of muscular power.