Intermediolateral nucleus

The intermediolateral nucleus is an aggregation of neuronal cell bodies located in the lateral horn of the spinal cord. It spans the T1 to L2 segments and plays a critical role in the autonomic nervous system. This nucleus gives rise to preganglionic sympathetic efferent neurons, which project to the sympathetic chain ganglia situated on either side of the vertebral column. Within the sympathetic chain, these preganglionic neurons either synapse immediately at a ganglion or travel up or down the chain to synapse with cervical or sacral ganglia, thereby innervating the cervical or pelvic regions, respectively.

It is important to highlight that the lateral horn of the spinal cord represents a lateral protrusion of the lateral intermediate substance, also known as Lamina VII. This structure is found specifically in the thoracic and upper lumbar spinal segments (T1 to L2). Consequently, the intermediolateral nucleus does not extend throughout the entire length of the spinal cord, as the lateral horn is absent outside of these regions.