We can divide both the gray and white matter of the spinal cord into regions, and more specifically nuclei and laminae (gray mater laminae or Laminae of Rexed).
The internal organization of the gray matter
These laminae are defined on the basis of neuronal size, shape, cytological features and density, and are numbered in a dorsoventral sequence.
Gray matter laminae of the spinal cord -- Polarlys -- CC BY-SA 4.0
- Lamina I (posteromarginal nucleus) – Contains small neuronal cells (Waldeyer’s neurons), the region of pain (nociceptive)
- Lamina II (substantia gelatinosa) – Contains small neurons, primary afferent fibers, also for pain