Posterior column—medial lemniscus pathway

Somatic sensory pathways carry information from somatic sensory receptors to the primary somatosensory area in the cerebral cortex and to the cerebellum. The pathways to the cortex consist of thousands of sets of three neurons classified as first, second and third-order neurons.

First-order neurons: impulses from somatic receptors to the brain stem or spinal cord.
Second-order neurons: impulses from the brain stem and spinal cord to the thalamus.
Third-order neurons: impulses from the thalamus to the primary somatosensory area of the cortex on the same side.

Somatic sensory impulses ascend to the cerebral cortex along three general pathways:

The posterior column-medial lemniscus pathway (impulses from the limbs, trunk, neck and posterior head).