“…60 Nail pits, ridges and grooves result from psoriasis of the nail matrix, whereas onycholysis, subungual hyperkeratosis, and splinter hemorrhages are attributable to disease of the nail bed or hyponychium. 61 Circular discoloration of the nail bed and hyponychium may resemble an "oil drop" below the nail. This observation represents histologically psoriatic change in the hyponychium.…”