Various levels of the spinal cord are shown in cross-sectional views - cervical (at the level of the enlargement), thoracic, lumbar (at the level of the enlargement), and sacral.

The interior of the spinal cord has the grey matter - composed of neurons, positioned in the interior and forming an "H" or butterfly-shape. Surrounding this is the white matter, consisting of tracts (pathways) of the spinal cord, both ascending (sensory) and descending (motor). {These pathways are seen and discussed in the next section of this Neuroanatomical Review.}