Transverse Section of Spinal Cord

i. The spinal cord is dorso-ventrally flattened due to the presence of deep, narrow posterior fissure and shallow, broad anterior fissure. The fissures divide the spinal cord incompletely into a right and left side.

ii. The fissures divide the grey matter into six horns, namely dorsal, lateral and ventral horns while the white matter is divisible into 6 columns or funiculi, namely dorsal, lateral and ventral funiculi.

iii. The H-shaped or butterfly shaped grey matter is on the inner side, while the white matter is on the outer side.

iv. The dorsal and ventral horns extend out of the spinal cord as dorsal root and ventral root of spinal cord respectively.

V. The dorsal root is connected to the dorsal root ganglion (lies just outside and lateral to the spinal cord). It has an aggregation/collection of unipolar sensory neurons.

vi. A central canal can be seen in the centre.

vii. The association or inter-neurons lie inside the grey matter. They receive signal from the sensory nerve, integrate it and direct the response towards the motor neurons lying towards the ventral horn. The lateral horns have neurons of autonomic nervous system (ANS). The nerves arising from these neurons emerge out from the ventral root of spinal nerve.

viii.The white matter consists mainly of bundles of myelinated nerve fibre called ascending and descending tracts. The ascending tracts conduct sensory impulses from spinal cord to the brain and these lie in the dorsal column/funiculi. The descending tracts conduct motor impulses from brain to the lateral and ventral funiculi of spinal cord.