Spinal cord: Cross section (Gray matter) (English)

Neurons of the posterior gray horn can be subdivided into four groups (nuclei): the marginal nucleus (Rexed lamina I), gelatinous substance (Rexed lamina II), nucleus proprius (Rexed laminae III, IV, V), and posterior thoracic nucleus (Rexed lamina VII). These nuclei function to receive and process sensory information carried by the posterior root of the spinal nerve. The lateral (intermediate) gray horn contains the intermediolateral nuclei (Rexed lamina VII), ​​which is a group of preganglionic sympathetic neurons. The intermediolateral nucleus is present only at the level of T1-L3 segments and functions to provide sympathetic innervation, which is transported to the sympathetic trunk via the white rami communicantes. Between S2-S4 is a sacral parasympathetic nucleus which is also considered to belong to Rexed lamina VII.The neurons of the anterior gray horn are responsible for motor innervation, carried by the anterior root of the spinal nerve. These neurons are divided into three groups: medial (Rexed lamina IX), central (Rexed lamina IX) and lateral groups (Rexed lamina IX). The medial group extends almost entirely throughout the length of the spinal cord, while the central and lateral groups are only present in some segments. The central group is found at the cervical and lumbosacral segments of the spinal cord and the lateral group is present only in the regions of the spinal cord responsible for motor innervation to the upper and lower limbs (C4 to T1 and L2 to S3). Rexed lamina X is located around the central canal at the gray commissure and is associated with the autonomic nervous system.