Base of posterior horn

The base of posterior horn is the region of the spinal cord situated ventral to the neck of the posterior horn. From a cytoarchitectural perspective, it corresponds to Rexed lamina VII, or with the lateral intermediate substance of the spinal cord.

Key nuclei located in the base of posterior horn include the posterior thoracic nucleus or the Dorsal nucleus of Clarke (a.k.a. Clarke’s column), and the visceral afferent nucleus. These nuclei are predominantly found in the thoracic and upper lumbar spinal segments and do not span the entire length of the spinal cord.

The posterior thoracic nucleus or the Dorsal nucleus of Clarke, present from C8 to L3/L4 spinal segments, plays a crucial role in receiving subconscious proprioceptive input from muscle spindles and Golgi tendon organs. It gives rise to axons that contribute to the dorsal and ventral spinocerebellar tracts, which relay proprioceptive information to the cerebellum for unconscious processing.

The visceral afferent nucleus is located just lateral to the Clarke’s column and is primarily involved in receiving visceral afferent signals.

In the T1 to L2 spinal segments, the base of posterior horn, which constitutes the lateral intermediate substance of spinal cord, extends laterally, forming a distinct structure known as the lateral horn. This lateral horn is noteworthy for housing sympathetic preganglionic neurons within these spinal segments.