Outer spino-thalamic conduction path

Tractus spino-thalamicus lateralis

Conduction pathway, outer spino-thalamic, Pain pathway

Ascending conduction pathway that conveys pain and temperature impulses from the whole body apart from the face with its cavities, i.e. the eye socket, nasal cavity and oral cavity.

The orbit starts from nuclei (nucleus postero-marginalis, nucleus proprius) in the back horn of the spinal cord. The nerve fibre bundles within one half of the spinal cord cross directly, at the level of the original segment, over to the opposite half of the spinal cord. The crossover occurs in front of the central canal and then, together with the wires from the opposite side, forms the anterior transverse connection of the spinal cord. After the crossover, the nerve fibre bundles make their way out towards the surface of the lateral cord and gather into the outer spino-thalamic conduction pathway.
The path becomes increasingly extensive the higher up in the spinal cord you go. It then continues up through the brain sacrum and ends in several different thalamus nuclei. The thalamus nuclei, in turn, transmit the pain signals to different parts of the cerebral cortex.