Dorsal column lesions are associated with loss of:
Ans: C (Proprioception) Ref: Harrison's Principles of Internal Medicine, 18th ed.Explanation:The posterior column (dorsal column)It 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 cuneatusIt 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 oi completely abolish tactile sensations and movement or position sense below the lesionTests of sensationModalityPathwayLight touchLarge fast-conducting axonsProprioceptionDorsal columnsVibrationMedial lemniscusTwo-point discrimination Pinprick (superficial pain)Smaller slower-conducting axonsSpinothalamic tracts Deep painTemperature StereognosisParietal cortex (only valid if peripheral sensory function intact)GraphaesthesiaTwo-point discrimination
Ankle jerk
Knee jerk
Proprioception
Superficial abdominal reflexes
C.N.S.