Author Duane E. Haines Ph.D. Professor and Chairman Department of Anatomy and Professor of Neurology and Professor of Neurosurgery at the University of Mississippi Medical Center Special Contribution By John A. Lancon M.D., F.A.A.P., F.A.C.S. Neurosurgeon St. Dominic Jackson Memorial Hospital; Clinical Associate Professor of Neurosurgery and Pediatrics The Blair E. Batson Hospital for Children, UMMC, Jackson, Mississippi M. P. Schenk BS, MSMI, CMI, FAMI Illustrator W. K. Cunningham BA, MSMI Illustrator W. A. Buhner BS Computer Graphics G. W. Armstrong RBP Photographer L. K. Boyd Typist Secondary Editors