Differences in spatial acuity between digits

The spatial acuity of the index, middle, and ring distal finger pads of eig ht right-handed men, aged 22 to 57 years, was measured by using gratings an d raised letters. Acuity declined significantly from the index to the middl e finger and from the middle to the ring finger. There were no significant differences between homologous fingers of tbe two hands. Letter recognition and grating orientation threshold measures were highly correlated.