Nissl staining shows location of cell somata. The dark spots are neurons of the groups. Note the ventral horn neurons for the foot. Dorsally, the substantia gelatinosa is formed of small neurons.

• Nissl staining shows location of cell somata. The dark spots are neurons of the groups. Note the ventral horn neurons for the foot. Dorsally, the substantia gelatinosa is formed of small neurons.

• Roots descending to vertebral foramen form the cauda equina that surrounds the cord and extends below the cord termination.