Evidence limiting the time of inception of intrauterine digital amputations.

Abstract

Evidence is derived from epidermal ridge configurations, in four subjects admitting diagnosis of congenital amputations (as opposed to agenesia), which points to the existence of the affection probably prior to the eleventh week of gestation. Three of the cases are considered in another publication, 1 where they are recorded as numbers 20, 508, and 509; a fourth, a still-born infant presenting multiple digital amputations in varied degrees, is comparable to 509.

It has been shown 1 that the alignment of epidermal ridges, hence their fashioning of patterns and of patternless series of ridges, is accomplished through the medium of growth forces obtaining in early fetal development. Such forces in growth vary locally, in accordance with the irregular molding of palmar and plantar reliefs. The influence on alignment hardly can be effective after ridges are initially elaborated (eleventh week), although it is possible that the regulation through growth may manifest its effect before the ridge anlagen actually appear. There is no evidence to show that a ridge arrangement, once effected, can be altered, barring, of course, its participation in the generalized increase of size. With this premise of permanence, coupled with the demonstrated genetic relation existing between the form of a part and the character of its ridge configuration, it is warranted to assume that a congenitally defective hand or foot will display configurations conforming to its particularized molding if the abnormality existed during the critical period of ridge determination. Such conformity is invariable in abnormalities which are initially present in the member (such as syndactylism, ectrodactylism, etc.). The conformity occurs also in the examples of amputation here reported, to the extent that the configurations are individually unique, being so far modified from the normal.