THE CONFIGURATIONS O F EPIDERMAL RIDGES I N A TIUMAN ACEPHALTC MONSTER, HAROLD (JUMMINS Depurtment of Anatonky, flw Tulane University of Louisiana SEVEN FIGURES TNTRODTT('TTON The accompanying description of epidermal ridge configurations in an Acephalus monobrachius is presented as the second contribution to a projected series of studies devoted to the configurations in developmental defects involving the hands, feet, and digits. This paper follows a report covering twenty cases of membranous and cutaneous syndactylism (zygodactyly ) of the second and third t0es.l F urther material now available comprises, especially, case6 of hyperdactylism, high-grade syndactylism, and ectrodactylism. A separate account of each variety i b desirable, in fact necessary, owing to the diversity and extent of the material. I n a final paper of the series the writer purposes to correlate the conclusions derived from the several defects, also to extend and amplify the survey of literature which was included in the introductory study. The observation of developmental defects provides a natural substitute f o r an experimental approach, which is not feasible, to the problem of what factors govern the disposition of ridges in patterns and patternless areas. It map be statad hew, briefly, that the varying interpretations of ridge direction a r e grouped into two classes. According to the one, emphasis is placed upon the facilitation of frictional and ' Cunimins, Harold, and Sicomo, Joseph. Plantar epidermal configurations in low-grade syndaetylism (7ygoll:ictyly) of the sccoud and third tors. vol. 25, no. 6 , 1923. .inat. Hec., -3 HAROLD CCMMINS tactual functions subserved by the ridge arrangements, and such arrangements a r e considered to be primary foci of evolution. An implication of a direct germinal provision for configurations, per se, is carried by this idea. On the otlicr hand, the second interpretation explains the direction of ridges simply on the basis of response to growth forces operating during the fetal period of ridge differentiation. The writpr's observations support the latter view. u ' r E 11I A1 1 The monster here reported was presented by Dr. I?. R. Towne, of Jackson, Michigan. I t was found, apparently after a preservation of years, in the course of renovating a hospital storage room. No label was attached to the specimen; therefore, its history cannot be stated. Since the specimen has not been dissected, identification as a n omphalosite is based upon external features only, and not upon the disclosure of an acardiac condition connoting a co-twin or the known existence of a co-twin. While it seems altogether probable that the idmtification is (.orrect, note should be made of the f a d ~ l i a l the purpose of the study does not require a diagnosis. Omphalosites furnish material wliich is singularly adapted to the rcyuirements of an investigation depending upon fortuitous and undesigned dcvelopmcntal abnormalities. A noteworthy advantage consists in their origin from germ plasm which probably is normal, and which if abnormal certainly cannot c a r q - specific gciininel deterniinants f o r tlie monstrous productions or for their aberrant configurations. Morcover, the diverse forms assumed by their estremities, when present, afford an excellent test of correspondence between contours and ridge directions. Another feature of patent value is their fetal nature. As is well known, the characteristic and distinctly prominent palmar and plantar eminences of the early normal human fetus become less and less prominent with advancing development. Postnatally, some of them are entirely obliterated, while thosc which persist do not retain C OXF IG CKh’I’IONS O F EPIDERMAL RIDGES 3 their original forms. It is not believed that the elevations described in this specimen have retained precisely their earlier form and relative prominence. To the contrary, the noriiial developmental history of such eminences probably is repeated here, although opportunely interrupted at a time when they still are distinguishable. 1)ES(‘ K I PTI 0s General The acephali, of which this specimen appears to be a representative example, are as a group characterized by the following external features? absence of head; usual absence of one o r both upper extremities, and these imperfect if present; fairly good development of trunk and lower extremities, although naturally imperfect ; frequent umbilical hernia ; ventral median thoracic fissure ; general edema. The specimen, a male, is shown in figure 1, which illustrates its conformity to the above characterization. The aspect chosen for the figure, a left-front view, fails to show the total absence of any superficial indication of a right upper extremity. Edema is indicated by numerous wrinkles, resulting from reduction of the edema in preservation. Left upper eictrewity The left upper extremity is represented by a n appendage 3 em. in length, showing both phoconiely anti ectrodactplism (fig. 1). Its outer and inner aspects are designated, respectively, as dorsal and palmar surfaces in conformity with the presence of a nail and ridge-bearing epidermis. Indicating tlic directions toward whicli they face, the remaining surfaces are named ‘front’ and ‘back.’ Distally, the extremity bears a short, bluntly rounded process 7 mm. wide (figs. 1 and 2), limited from the proximal and broader portion of the extremity by a slight constriction. A very small nail is present on the dorsal aspect of this ‘Hirst, B. C., am1 Picrsol. Grorge A., Human ~nonstrositics,P a r t ITT. (lclpliia, 1892. Phila- 4 HAROLD C U M M I N S process, which is the only digit present. Viewed from the distal end (fig. 4), the digit is almost round, but there is an asymmetry of contour which throws its maximum dorsopalmar dimension toward the front margin. A similar but less marked asymmetrv is evident dorsally, where a slight Fig. 1 Acephalus monobrachius, left-front view, x 1/2. Kotc the rudimentary left upper extremity, representing one digit and a palm attached directly to the shoulder, the maldevelopinent and talipes varus of the feet, umbilical hernia, ventral median thoracic fissure, absence of head (the irregular prominence sur mounting the thorax may represent a n abortive head formation). The numerous wrinklcs result from reduction of the edema in preservation. eminence is situated toward the back margin. The dorsal slope of the distal end of the digit shares a small part of this eminence, but the elevation diminishes in its distal extent. The digital configurations are to be described under the following heads: 1) apical pattern, 2) accessory distal configuration, and, 3) transverse ridges proximal to the apical pattern. CONFIGURATIOXS O F EPIDERMAL RIDGES 5 1. The apical pattern is a whorl, as shown in figure 2. No additional description is necessary. However, attention is called to its asymmetry in form and position. The core of the whorl is situated upon the greatest eminence of the ball, which, as noted above, deviates toward the front margin. Fig. 2 Palmar surface of the left upper extremity, showing eonfigurations of the single finger and palm. The head of the palmar loop, which extends upon the front margin and dorsum of the palm, is shown without the front boundary of the palm, in the conventional manner of representing patterns on upturned surfaces. This and the succeeding illustrations of configurations do not purport t o possess the precise accuracy which obtains in tracings from actual prints. The study of these configurations was made, necessarily, on the specimen itself, under low magnification. While precautions were followed, including repeated checking of the original drawings, to ensure as accurate a reproduction as possible, the lines do not represent the exact courses of individual ridges, but rather, the general courses of ridges within the area. Fig. 3 Dorsal aspect of the finger, showing atypical configurations. The nail bed is shown in solid black. Fig. 4 Outline of the ball of the finger, as viewed from the distal end. Note the asymmetry of the apical pad, displacement toward the front margin, left in the figure. Also observe the slight elevation of the dorsal surface, toward the back margin, right in the figure. The apical and accessory distal configurations are borne upon the respective elevations. Fig. 5 Outline of the mid-portion of the palm, as viewed from the distal end. Note that its greatest dorso-palmnr dimension is situated toward the front margin, left in the figure. The greatest elevation of the palmar surface marks the point, shown in figure 2, where arciform ridges of the palm course around the prmimal radiant of the p21ni:ir triradius. 2. I n figure 3 a r e shown the dispositions of ridges which occur upon the dorsum of the digit and the slope of its distal end. Especially notewortliy is the presence of a small loop, its core being situated upon the maximum elevation of the small dorsal eminence noted above. 3. Transverse ridges occupy the interval between the apical pattern and a triradius of tlic palm (fig. 2). Their ends C O U ~ S ( ' dorsally over the front and back surfaces, thus presenting no dcpartures from the normal. The remaining part of the extremity, the palm, is pad-like in shape, compressed in tlie dorso-palrnar dimension, and attached directly to the trunk by a constricted pedicle. There is marked asymmetry in its transverse outline (fig. 5), its iimsimum tliicdmc ss Iwiiig toward t l ~ efront margin. Located in about tlie mid-portion of the front margin, and extended upon tlie dorsum, tlwrci is a lorn hut extensive elevation, not shown in the figures. d conspicuous feature of the palmar configurations is a large loop. The head of the loop coincides with the front and dorsal cllcvation just mmtioned. The writer hesitates to Iiomologizc this pattei,i with any component of the normal palmar configurations. F o r this and other features of the palm see figure 2. The presence of a single (digitall) triradius is to be noted; it is determined distally by transverse tligital ridges and proximally b y arciform palmar ridges coursing in two directions. Thc most proximal of these arciform ridges form a complete arch, the apex of which marks tlic greatest elevatioii of the palmar surface. Lozuct. cxtl-ernities Both lower cstr~iiiitics cxliibit marked talipcs Tarus (fig. 1) and defective digital development (figs. 6 and 7). Since the identities of certain digits a r e questionable, reference will be made to them as A, B, C, and TI, in order, beginning on the tibia1 side. CONFIGURATIONS OF EPIDERMAL RIDGES -I Rigkt (fig. 6) Only four digits are present (ectrodactylism), and two of them are joined by skin bands (cutaneous syndactylism) . There is a possibility that C and D are not digits 4 and 5, as they appear to be, but are the result of duplication of either 4 or 5 with coexisting syndactylism. t A 6 7 Fig. 6 Plantar configmations of the right foot. Note the absence of one digit, the cutaneous syndactylism of C and D, and the nonnal contours of A .iiitl R The configurations of A and B, as well as the neighboring region of thc sole, are not atypical, while the ridge directions of C and D, also of the adjacent sole area, exhibit variants of a type previously found to be associated with lowgradc syndactylism. Fig. 7 Plantar eonfigurntions of the left foot. Observe the absence of one digit, the cutaneous syndactylism of A and B, and the atypical forms of C and D, especially the latter. Note the atypical ridge directions of C and D and of the sole. Compare thc digital configurations of A and B with those of C and D of the right foot; the variants are of the same fundamental typc, differing only in the degree of approximation of the apical patterns. A and B are typical in form, as compared with the toes of late normal fetuses, Each of these digits is bulbous distally, in that the plantar surface of each is decidedly swollen into an apical pad. Their configurations are not atypical. C and D show certain features which are worthy of especial mention. The apical pattern of D, a fibular loop, is displaced laterally and distally, lying upon a prominent elevation of the latero distal surface of the digit. Apart from this deviation, the 8 HAROLD C U M M I N S configurations are fundamentally like those of an adult syndactyl, case 202, described and illustrated in the previous paper. The sole is wrinkled, rendering a determination of its original contours impossible. Distally, the sole shows a hallucal pattern of a common type, an open field first interdigital pattern, also of a common type, and an open field related to C and D with ridges opening to the fibular margin. The lastnamed condition, associated with the absence of a critical digital triradius, is of syndactylous significance. The entire proximal portion of tlie sole is covered with parallel ridges which course approximately transversely,' except for a very small hypothenar loop lying upon the fibular border of the sole. Left (fig. 7 ) Only four digits are present (ectrodactylism) ; two of them are joined by skin bands (cutaneous syndactylism) ; and one is distinctly abnormal in form (perodactylism, in a strict sense). The skin bands which unite A and B are not so extensive as to fuse the digits to their very ends. Aside from their union, these digits are normal in form, and their configurations show only such departures as have been noted in digital fusions. C, while isolated, is rather atypical; its distal end is attenuated and bluntly pointed, with no suggestion of the bulbous appearance which arises from the presence of a normal apical pad. I t s apical configuration is a simple arch, only one limb of the arch being located on the plantar surface; the other limb is extended over the tibia1 side and dorsum. The apex of the arch is related to the bluntly pointed end of the digit. D, the only toe of either foot which does not bear a nail, is sharply pointed and thus has no resemblance to a normal digit at any stage of development. The ridges on its plantar surface course in a direction which is oblique t o the long axis of the digit. At the extreme distal end, and extend- CONFIGURATIONS O F E P I D E R M A L RIDGES 9 ing slightly upon tlie dorsum, there is the core of a whorl, not shown in figure 7. Ridges on the plantar surface are gently arciform, in accommodation t o tlie rounded surface. If these arcs were extended hypothetically around the dorsum the result would be a complete whorl, its core actually present upon the apex of this sharply conical elevation. The sole, which is not wrinkled as in the right foot, is subcylindrical, convex from side to side. Excepting for the loop which probably represents a hallucal pattern, the sole is covered with parallel ridges ; these ridges course practically transversely across the tread area and turn vertically upon the upturned ridge-bearing area of the tibia1 and fibular margins. The ridges which occupy the digital area region are wider apart, as if from distension. SUMMARY AND DISCUSSION The palmar and plantar surfaces of the monster exhibit structurally normal epidermal ridges, with rows of sweat pores. I n only one relatively small area, the digital area region of the left foot, do these ridges exhibit evidence of irregularities arising subsequent to their histological differentiation. Since the alteration consists of a widening of the intervals between ridges, it is suggested that the epidermis may have been extended in the long axis of the foot by subjacent edema, or perhaps by a localized overgrowth in this region. Elsewhere, the interrelationships of the ridges to each other and their adaptation to the surfaces are perfect. This circumstance indicates the existence, a s in the normal, of a mutual correlation in the growth of surfaces and the differentiation and growth of the ridges which they bear. In organizing the descriptive matter on the directions of ridges, two headings are suggested by the aim of the study: 1) ridge directions which can be correlated with contour, and, 2 ) ridge directions which cannot be so correlated. 1. The first head is divided naturally into: A) patterns which are typical, that is t o say, patterns which are similar 10 HAROLD CUBSMINS in forni and position t o those in the normal; B) atypical patterns of syndactylous significance, and, C) other atypical patterns. A. The digital configurations, including apical patterns and basal transverse ridges of the finger and digits A and B of the right foot, are typical. It will be recalled that each of these digits has an apical pad, upon which the apical pattern is situated. I n the case of the finger it is possible to further correlate an asymmetry of the pad with asymmetry of the pattern. In each case the basal transverse ridges are related to the more constrictcd part of the digit, the region whic~11 is convex from side t o side. It is apparent, then, that typical configurations in the instances cited are concurrent with normal form o r contour of the digits. B. Of the syndactyl variants, little need be said, inasmuch as they have been discussed previously. Attention is called to the fact that the adult material includes cases in which toes 2 and 3 are joined, with only occasional and slight involvement of 4. I n such cases there are pronounced ridge cleviations of the neighboring interdigital areas, when these arc open fields, together with the obliteration of critical digital triradii. Significantly, the right foot of the monster, with syndactyl toes C and D, shows a like ridge deviation and loss of a triradius in the axis of these digits. This finding verifies a conclusion previously stated, namely, that the variants of interdigital areas are a proximal expression of syndactylism. -\berrant configurations of the syndactyl digits, C' and 1) of the riglit foot and A and B of the left, require no particular niention, since they are essentially like those already described. Exception must be made, however, of the displaced apical pattern of D-a variation which is probably genetically independent of the digital union; this mill be noted under the nest heading. C. Other atypical patterns are of prime interest, since for each of them, as pointed o u t above, it is possible to distinquish a dcfinite correspondence between contonr and ridge C O N F I G U l L i T I O N S O F E P I D E R M A L RIDGES 11 direction. The following configurations are included : u ) the accessory distal configuration of the finger; b ) the palmar pattern; c ) the displaced apical pattern of digit D of the right foot; d and e) the generally abnormal configurations of digits C and I> of the left foot, and, f ) the transverse direction of ridges over the left sole, associated with total absence of three interdigital patterns. 2. No significance is attached to the failure to ascertain a correspondence between contours and configurations in two locations, namely, the entire right sole and the hallucal region of the left. I n explanation of the first instance it may be repeated that the riglit sole is extensively wrinkled; while this distortion does not prevent the observation of configurations, it serves t o obscure and even obliterate the original contours. The apparent lack of a pad related t o the hallucal pattern of the left sole may be due, possibly, to the diminution of a previously existing eminence to a degree where it has become indistinguishably elevated above the relatively large sole area with which comparison necessari1;- is made. The data assembled above admit tlic following propositions : 1) A monster possessing varied defects of the extremities exhibits typical ridge differentiation of the palmar and plantar epidermis. To surface inspection, these ridges are normal and are, moreover, arranged in configurations, inchiding loops, open fields, etc., all of them equivalent in their forms of surface sculpturing to configurations in the normal. 2) However (see ‘Other atypical patterns, ’ above), certain ones ( c and d ) which are apparently homologous t o particular configurations in the normal are displaced from the normal positions. Others (0,h l , and e ) appear to be supernumerary, n o t represented by any corresponding configurations in the normal. Yet another ( e ) shows a remarkable departure from the typical ridge directions in the region involved; no plantar surface hitherto recorded approaches so ncarly to a uniformly transverse ridge direction as does the left sole. I n each of the above instances thc atypical configuration is associated I:! HAROLD CUMMINS with abnormal contours of the area occupied. 3 ) Several variants (see ‘Atypical patterns of syndactylous significance, ’ above) a re attributed to the presence of digital fusions. 4) Typical configurations do occur, the criterion of such being the coincidence of normal situation and morphology. In three digits it has been possible to establish the existence of normal contours, coexistent with their typical configurations. Unfavorable circumstances at the sites of other typical configurations have prevented a determination of their contours. Upon passing to a consideration of the bearing of these findings upon the qnestion of what factors determine configurations, the two divergent views should be recalled. Are the several typical configurations present because certain specific germinal determinants were for some reason immune t o the developmental disturbance which involved the fetus as a whole; and do the aberrant configurations owe their origin to a vitiation of such determinants? O r are all the configurations, typical and atypical, elaborated through the operation of other factors, with no provision for configurations, as such, in the germ plasm? I t appears likely, f o r the fetus probably is a n omphalosite, that the germ was normal, the monstrous development being initiated by vicious circumstances manifesting themselves sonic time subsequent to fertilization. Granting normal germ plasm, an hereditary transmission of the bizarre patterns is precluded, since at least some of them have no known parallels in the normal configurations. Although the germ may have been abnormal, i t did not, naturally, carry predetermined factors for the atypical configurations any more than it bore detcirminants for the particular development of the monster. I n either event, epidermal variants must be explained by a disturbance of germinal configuration determinants or by the admission of an immediate control of ridge dirwtion which is not fisedly predetermined. Each of the atypical configurations has been correlated with variations of contour, and a definite correspondence between C O N F I G U R A T I O N S O F E P I D E R M A L RIDGES 13 the character of the contours and the type of configurations is apparent. Moreover, there is a correspondence of normal contours and typical configurations in three digits. These consistent correspondences between contours and configurations, whether typical or atypical, indicate an orderly relationship between the two. Since contours of the palmar and plantar surfaces, as elsewhere, are expressions of growth complexes which vary locally in accordance with the form being attained, the indication is that a control of ridge direction is exercised by phenomena of growth. It is to growth forces, presumably those existing during the fetal period of ridge differentiation, that the writer attributes the alignment of epidermal ridges. Accordingly, there is no specific provision in the germ plasm for configurations. The epidermis in its ridge-formative state is apparently plastic ; its potentialities of ridge direction are unlimited, although in the normal course of events restricted in their expression by the range of variation of growth forces. The atypical configurations here described result from a vicarious determination of ridge (direction. These configurations are elaborated through growth complexes which are altogether foreign to the homologous areas of the normal palmar and plantar surfaces. While the same mechanism of growth forces is immediately responsible also f or the normal configurations which occur, there is a directive element which must not be overlooked. I refer t o a possibly directly germinal regulation of contour, through which is mediated a domination of the epidermis, hence admitting a secondary r61e of the germ in the control of configurations. Such a control is palpably not rigid and infallible, but is limited by the labile nature of the mechanism.