Which lies in the dorsal column of spinal cord:September 2007
Ans. A: Fasciculus gracilisFasciculus gracilis and fasciculus cuneatus lies in the dorsal column.It is pa of an ascending pathway that is impoant 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 pa 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.
Fasciculus gracilis
Anterior spinothalmic tract
Dorsal spinocerebellar tract
Ventral spinocerebellar tract