On the left is the spinal cord with the fore roots and spinal ganglia seen from the front. The green crossbars indicate the position of the cross-sectional levels on the right side of the image. Notice how the spinal ganglia are gradually displaced, counted from above, downwards relative to the spinal cord segments to which they are connected by their hind roots. As a result, the spinal ganglia are located at the level of the respective spinal cord segments only within the upper part of the vertebral column. Also notice that the segment C1 usually lacks ganglion and hind root and is equipped only with a front root pair.