Development of the spinal nerves. A, Formation of nerve roots. B, Formation of nerve trunk (N).C, Formation of nerves. D, E, Formation of subordinate branches. F, Formation of nerve trunks in relation to the limb: dorsal and ventral trunks corresponding to lateral and anterior trunks in D and E. Labels: D.R., dorsal root; A1.C., alimentary canal; V.R., ventral root; Ao, aorta; N.T., neural tube; V., cardinal vein; No., notochord, M.P., muscle plate; D.G., dorsal ganglion; Sy., sympathetic cord; W.D., wolffian duct; Co., coelom; So., somatic division; V1, visceral branch; P, posterior primary division; Lat, lateral branches; Ant., anterior branches.

Development of the Spinal Nerve

Development of the spinal nerves. A, Formation of nerve roots. B, Formation of nerve trunk (N).C, Formation…