Shortened fifth middle phalanges, defined as being less than half the length of the fourth middle phalanx, were found in 12 of 96 Philadelphia Chinese and none of 200 Philadelphia Negro children. At least nine of these can be characterized as having stunted cratered diaphyses, with precocious cone epiphyses, which underwent very early epiphyseal union.
The possible extension of a current vascular hypothesis for cone epiphyses, to include inherited osseous variation in this region of the little finger, is discussed.
A classification of metacarpal brachydactyly is presented, with the intention of investigating the syndrome of pseudopseudohypoparathyroidism. Reports of cases which have been held to negate the theory that Albright's hereditary osteodystrophy is sex linked were found to have the pattern of phalangeal shortening exhibited by one of the forms of metacarpal brachydactyly. This finding lends support to the contention of others that these reported cases are not pseudo-pseudohypoparathyroidism.
