Posterior column or dorsal column refers to the area of white matter in the dorsomedial side of the spinal cord. It is made up of the fasciculus gracilis and fasciculus cuneatus and itself is part of the dorsal funiculus. It is part of an ascending pathway that is important for well-localized fine touch and conscious proprioception called the posterior column-medial lemniscus pathway.
Joint capsules, tactile and pressure receptors send a signal through the dorsal root ganglia up through the fasciculus gracilis for lower body sensory impulses and the fasciculus cuneatus for upper body impulses. Once the fasciculus gracilis reaches the nucleus gracilis and the fasciculus cuneatus reaches the nucleus cuneatus in the lower medulla, they begin to cross over the medulla as the internal arcuate fibers. When they reach the contralateral side, they become the medial lemniscus, which is the second part of the posterior column-medial lemniscus pathway.
Lesions in this pathway can diminish or completely abolish tactile sensations and movement or position sense below the lesion.
Famous quotes containing the word column:
“Averageness is a quality we must put up with. Men march toward civilization in column formation, and by the time the van has learned to admire the masters the rear is drawing reluctantly away from the totem pole.”
—Frank Moore Colby (1865–1925)