A. Coronal section of the vertebral canal from the posterior view. B A. Coronal section of the vertebral canal from the posterior view. B. Cross-section through the back showing spinal roots, nerves, and rami. Spinal nerves branch into a posterior ramus (mixed), which transports sensory neurons from the skin of the back to the spinal cord and motor neurons from the spinal cord to the erector spinae muscles. C. Caudal end of the vertebral canal revealing spinal roots forming the cauda equina before exiting the vertebral canal through the intervertebral and sacral foramina. Source: Chapter 1. Back, The Big Picture: Gross Anatomy Citation: Morton DA, Foreman K, Albertine KH. The Big Picture: Gross Anatomy; 2011 Available at: http://accessanesthesiology.mhmedical.com/DownloadImage.aspx?image=/data/books/mort/mort_c001f007.gif&sec=40140157&BookID=381&ChapterSecID=40140006&imagename= Accessed: November 02, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved