Sensory functions in limbs of normal persons and leprosy patients with peripheral trunk damage

The threshold to touch was tested in hands and feet of normal persons using Semmes-Weinstein graded monofilament nylons. The minimum stimulus to which response could be elicited was nylon number 3.61 in palms and 4.31 in soles. These numbers relate to the logarithm of the force applied, 3.61 corresponding to 0.217 gm force and 4.31 to 2.35 gm force respectively. The area of pain insensitivity complained by the patient more or less corresponds to that revealed by objective testing. It was interesting to observe that loss of pain sensitivity was confined to a smaller area compared to touch and thermal insensibility in the part innervated by the same nerve trunk.