Chapter 3 The Different Parts of the Nervous System 73 Figure 3.3 The spinal cord. To the left, the cord from the ventral side. Note the cervical and lumbar enlargements. To the right, the cord and the vertebral column from the side, but the right halves of the vertebrae have been removed to expose the vertebral canal with its contents. Below the first-second lumbar vertebrae, the vertebral canal contains only nerve roots (the cauda equina). Note that the roots unite to form the spinal nerves. upper margin of the second 1umbar vertebra (L2). Here the cord has a wedgeshaped end ca11ed the medullary conus (or simp1y conus). In children the spinal cord extends more cauda11y, however, and reaches to the third 1umbar vertebra in the newborn. This difference between the position of the lower end of the spinal cord in adu1ts and infants is caused by the vertebral => page 74    start page