B. Vijaya Bhanu Simian Crease in Man: Some Methodological Considerations

Department of Anthropology, Deccan College Post-Graduate and Research Institute, Poona-6, India

Received 9 August 1972

There is no agreement among worken in defining the Simian crease, thus making it difficult to compile or compare their works. The Simian crease, invariably present among anthropoid apes and frequent among mongoloid idiots, is also present in varying degrees among normal populations. Mode of inheritance of this trait is not yet established. This paper attempts to examine critically the definitions and classifica- tions forwarded by various authorities. A new definition has been suggested considering the course of both the distal and the proximal creases. A new classification, to include all transitional variations has also been proposed. A progressive transition from the typical Simian crease to the normal crease configuration is recognized. Further investigation to assess the hereditability of Simian as well as normal creases is emphasized.

1. Introduction

For a long time the Simian crease, a single transverse crease on the human palm, has been a source of considerable interest for palmists, primatologists and physical anthropologists. The palmist views its presence as an indication of strong will power. Some societies attribute criminality and other anti-social stigmas to the occurrence of the Simian line on the human hand. It is invariably present among anthropoid apes; though uncommon in normal persons, it occurs quite frequently in mongoloid idiots (Bettman, 1932). The anthropological significance of this trait was drawn by Paul Broca (1877) when he first noticed the crease in varying frequencies among normal individuals of different racial origin. Langdon-Down (1909) recognized the trait as being associated with mongolian imbecility, (also called Down’s Syndrome) characterized by certain bodily defects and an overall retardation of growth; chromosomal aberration (Penrose, 1963) is considered to be the cause for this syndrome. Brachymesophalangia-5 is more frequent among Down’s syndrome patients (Garn, Gall & Nagy, 1972).

A large number of ethnic and genetic studies on the Simian crease are now available (note, among others: Chakravartti & Basu, 1960; Beckman, Gustavson & Norring, 1962 ; Papp, 1964; Rashad, Morton & Scally, 1964; Achs, Harper & Harrick, 1966 ; Lestrange, 1966 ; Plato, 1970).

Unfortunately, various workers followed different nomenclatures, definitions and classifications in describing this trait. This has lead to enormous confusion and rendered several outstanding contributions uncomparable. It is felt desirable to have a proper terminology, definition and an adequate method of classification which would include, and at the same time recognize all the phenotypic variations of this trait, so as to avoid further confusion. The aim of this paper, therefore, is to examine critically various definitions and classifications offered by previous workers in order to achieve a certain amount of standardization in techniques. A modified definition has been suggested. A new classification has also been offered, keeping in view the various transitional types presented by the distal and the proximal flexion creases. It is hoped that the present classification will not only minimize the error of subjective judgement in analysing this qualitative trait, but will also faithfully record the various manifestation of Simian crease, which might have evolutionary implications.

Journal of Human Evolution (1973) 2, 153- 160

154 B. V. BHANU

2. Definition

The definition of Simian crease varies from author to author. Paul Broca (1877) defined it as “a perfectly transversal crease continuous for the entire width of the palmar region”. Langdon-Down ( 1909) described it as “the tendency of the principal fold line to be two in number only instead of three as was most commonly the case”, A similar definition “ . . . instead of a distinct line of heart and a distinct line of head one transverse line only” was suggested by Crookshank (1924). Penrose (1949) defined it as “a single transverse crease”. Definitions forwarded by Wiirth (1937), Tillner (1953) and Weninger & Navratil (1957) are alike. The Simian line has been described by Cummins & Midlo (1961) as “a modified distal transverse flexion crease coursing continuously from radial to ulnar margins of the palm”. Lestrange (1969) recognized a transverse crease “when the normal creases 2 and 3 (proximal and distal creases) are replaced by a single crease which crosses the palm from the radial to the ulnar edge, whether other vestigial portions of crease 2 and 3 remain or not”.

Sarkar (1961) critically examined and compared the works done by various authorities who studied and recorded the morphological variations of the flexion creases on the palms of anthropoid apes and some monkeys. Details presented in Table 1, shows the type,

Table I* Number, type and side of origin of various creases among anthropoid apes

Species

Sarkar Number (1961) of Flexion Side Fig. creases crease (s) of IlO involved involved origin Observer

Orang Orang Orang Young Gorilla

Gorilla Gorilla

Chimpanzee Chimpanzee

D.F.C. Ulnar Crookshank (1924) P.F.C. Radial Sontang (1924) P.F.C. Radial Wood Jones (1929) D.F.C; P.F.C. Ulnar; Radial Duckworth (1915) D.F.C; P.F.C. Ulnar; Radial Sontang D.F.C; P.F.C. Ulnar; Radial Wood Jones P.F.C. Radial Wood Jones P.F.C. Radial Sontang

D.F.C. Distal Flexion Crease; P.F.C. Proximal Flexion Crease. * Table prepared after Sarkar (1961).

number, point of origin and course of the major flexion creases. A great deal of pheno- typic variation has been observed on the course of these creases even among the individuals of the same species of the anthropoid apes. The number of flexion creases also varies from a single line across the palm to as many as four creases running parallel to one another or in combination. In some cases both the proximal and the distal creases combine to form a single crease running across the palm. Sarkar (1961) had posed a question as to which of the creases on the human hand may be called the Simian crease. None of the definitions mentioned above provides an answer to this. No author seem.s to have picked out any flexion crease to be called a Simian crease, except Cummins & Midlo (1961) who mention a “modified distal transverse flexion crease” and go on to say that it “courses continuously from radial to ulnar margin of the palm”. We know that the distal flexion crease on the human palm usually originates from the ulnar margin and traverses to the distal margin, i.e. II interdigital area of the palm. This crease peculiarity has also been observed among the anthropoid apes by various workers.

SIMIAN CREASE METHODOLOGY 155

Table 1, prepared after Sarkar (1961) shows that the distal flexion creases among all the anthropoid apes invariably originate from the ulnar margin of the palm and traverse across to the radial margin. The proximal flexion crease, on the other hand, develops from the radial margin and traverses across to the ulnar side. Bfichi (1954) considers that the distal flexion crease originates from the ulnar margin and runs towards the interstitium between fingers II and III.

Nevertheless, all the definitions cited and examined above invariably consider a single transverse crease (typical Simian crease) which is supposed to be the product of a union of both the distal and the proximal transverse creases and either ignored the transitional types or paid little attention to them. In many of the palm prints examined, the present author has observed either a distal crease or proximal crease alone extending both the margins of the palm, and according to the existing definitions and classification this condition would not be considered as a Simian crease. Thus it is very necessary to modify the definition so that any of these two creases traversing the palm is also taken into account, without altering the basic concept implied in the Simian crease. The modified definition is as follows: either of the two flexion creases distal and proximal, independently or in combination, traversing both radial and ulnar margins of the palm, may be called a Simian or Transverse crease (s).

This definition would thus take care, not only of the typical Simian crease, but various transitional forms, so vital in understanding the evolutionary significance of the Simian crease, would also be known. Usually three major flexion creases, are present on the human palm (Figure 1). The radial longitudinal crease curves and covers the thenar eminence, the portion occupied by interdigital pad I. The proximal flexion crease originates from the interdigital area I and traverses down to a proximo ulnar direction.

Figure. 1 Human palm showing the normal crease arrangement.

D~stol

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156 B. V. BHANU

The distal flexion crease emerges from the distal ulnar margin of the palm and taking a slight transverse course runs distally toward the interdigital area II. Students of palm- istry recognize these creases as lines of life, head and heart, respectively.

3. Classification

Portius (1937) for the first time classified various types of Simian creases into four types (Figure 2) a transitional type and two incomplete types in addition to the typical com- plete form. Weninger & Navratil (1957) added one more incomplete type (Type IIa). Biichi (1954) offered a better classification. His type II (incomplete) was an addition to the classification of the previous worker. Instead of types III and IV of Portius, and Ia and Ib of Weninger & Navratil, Biichi had only one type i.e. Type V. Kimura (1968) classified the transverse creases into 16 types (nine complete and seven incomplete) based on the collation of the fundamental palmar creases. However, his consideration of the position of the crease bases is of little help if not absolutely unnecessary in the diagnosis of the Simian crease types. The main components of the Simian crease are the distal crease and the proximal crease only. The longitudinal crease neither contributes to the formation nor decides the course of the two former creases. Kimura’s attempt to classify the Simian crease types with reference to the placing of the longitudinal crease (point of origin at the first inter digital margin) is therefore not justified. Barring the longitudinal crease position Kimura’s classification of transverse creases into 16 types can be effectively reduced to 10 types (five complete and five incomplete). However, Kimura’s classifica- tion recognized some more types which were not considered by the previous workers. His types C, D and E and a, b, d and e were additions to the previous classification. Unfortunately, the type III of Portius and type Ib of Weninger & Navratil were not included either in Btichi’s (1954) or in Kimura’s (1968) classification.

Lestrange (1969) forwarded a classification (Figure 2) incorporating 11 types of Transverse creases. He included three more type variations. These are 3 -+ 2 + f, 2 -+ 3 + f and 3t. His type 2t, though it differs slightly from Kimuras type D, may be considered as the same. Lestrange’s type 3 --f 2 and Kimura’s type b were not considered by any of the previous workers. Lestrange’s type Pts has not been accounted by any other worker. The types B, C, E and a of Kimura, have been wisely replaced by a single type, PTR by Lestrange. The replacement is also justifiable from a practical viewpoint. The minor crease course variations, if taken into consideration for the purpose of type recognition, however, would account for innumerable “type” variations of the course of these two creases alone. Lestrange’s classification no doubt would record most of the major type variations. However, there is no provision in his classification for recording the typical transitional type, which has been recorded by all other workers (Type 1 of Portius and of Buchi and incomplete type c of Kimura) except by Weninger & Navratil. The transitional type should be considered as an important stage where both the proximal and the distal flexion creases diverge and subsequently lose the “bond” (connecting bridge between both the creases) to transform it into a normal crease configuration on the human hand. A high incidence of this transitional type is observed among all populations studied by the present author and a plea is made that this type should in- variably be recorded by all workers. This would be of help in understanding the evolu- tionary significance of the Simian crease. Lestrange’s type “Pant”, another type variation recognized by all other workers, does resemble the typical transitional type; but is distinguishable by the course of both the proximal and the distal creases and also by the absence of a slanting bond. Lestrange’s type 3t and Pts are but variations in the

SIMIAN CREASE METHODOLOGY 157

Figure 2. Dia grammatic presentation of various classifications of Simian crease types. (In Kimura’s classification palms with broken outline represent “incomplete” types.)

Kunum (1966) Lestrange (1969)

EZ Ia P A:Aa PT 13

nature of course of the same crease. Similarly type 3 -+ 2 and PtR are but two variations

of the same crease types, and thus the types Pts and 3 -+ 2 could very well be eliminated without any disadvantage to the accuracy of classification, reducing the total types to nine instead of eleven.

Thus a close examination and a subsequent attempt of classification of Simian crease types from any series of palmar prints would easily prove the inadequacy of the existing classification. A modified classification, considering the course and subsequent union of the proximal and the distal flexion creases, has been proposed (Figure 2). In all, there are 13 different ways in which the proximal and distal creases arrange themselves. These

main types are named and described below: Type 1. Transitional type

Both the proximal and the distal flexion creases take their normal courses, but con- nected by an oblique bridge, both ends of which if extended would traverse and con- verge to the points of origin of both the creases. Type 2. The distal crease bpe

The distal flexion crease crosses from the ulnar margin to the radial margin of the palm. The proximal crease takes its normal course. Type 3. The proximal crease @pe

The proximal flexion crease courses from the radial margin to the ulnar margin across the palm, while the distal crease takes its usual course. Type 4. The parallel crease ape

Both the distal and the proximal flexion creases run parallel to each other, extending completely over the breadth of the palm.

158 B. V. BHANU

Type 5. Complementary bicrease &pe

The distal parts of both the proximal and the distal creases are recognizable as branches of a more or less straight crease across the palm. Type 6. Complementary proximal crease gpe

The distal crease traverses across the palm and fuses with the proximal crease, the distal part of which is still recognized as a branch of a straight crease. Type 7. Complementary distal crease ppe

The proximal crease runs across the palm joined by the distal crease, the distal part of which is still recognized as a branch of a straight crease. Type 8. Complementary-vestigial (Proximal) type

Complementary proximal type, with the distal end of the distal crease separated from the transverse crease. Type 9. Complementary-vestigial (distal) gpe

Complementary distal type with the distal end of the proximal crease separated from the transverse crease. Type 10. Vestigial bicrease bpe

The distal ends of both the distal and proximal creases, though visible, are completely separated from the single transverse crease. Type 11. Vestigial proximal crease &pe

The distal end of the proximal crease, though visible, is separated from the complete transverse crease. Type 12. Vestigial distal crease Qpe

The distal end of the distal crease is visible as separated from the complete transverse

crease. Type 13. Typical Simian (transverse) crease ape

A single complete transverse crease. Neither the proximal crease nor the distal crease

or any part thereof is identifiable. It is hoped that the proposed classification will cover within its 13 types, not less than

99% of the variations shown by the Transverse creases. Recently, the present author examined palmar prints, of about 400 people belonging to four endogamous groups, of different origin, Out of the 800 palms examined, only nine palms were left as “un- classified”. However, out of these nine palms seven could be “classified” since they presented some sort of combination of two types. Three out of these seven palms showed a condition in which types 3 and 6 were involved. Two palms showed a combination of types 3 and 11. The remaining two palms presented a pattern combination of the types 2 and 12. Only two palms, showing complicated crease formations, were thus left out as unclassified. In dual formulation, distal crease type was first recorded followed by the proximal crease type-both the type numbers being separated by a slant line, i.e. 316; 3/l 1; and 2/12. Detailed analysis of these 800 palms will be presented in a separate paper.

4. 6cFamily Tree?

It is interesting to note that all the workers, classifying various types of Transverse creases invariably recognized a transitional type which occurs quite frequently in all the series of palm prints. The exact significance of such transitions is yet to be understood and the underlying causes for type differences and affinities are yet to be worked out. An attempt

has been made in the proposed classification to arrange different Simian crease types

SIMIAN CREASE METHODOLOGY 159

making a “family tree” illustrating a progressive transition from a typical Simian crease (Type 13) to a transitional type (Type 1) and then to the normal condition, on the human hand. The successive connecting steps are shown in Figure 3. Does this sequence

Figure 3. Schematic arrangement of Simian crease type numbers showing successive connecting steps from Typical Simian crease to normal crease arrangement.

6~2-4

of crease types correspond to an actual evolutionary order from the anthropoids to hominids ? It is premature to draw any vast conclusion on the available material due to lack of evidence for the exact mode of inheritance of Simian crease. While Portius ( 1937) considers its inheritance as a recessive trait, Steffens (1953) holds that it is transmitted as a Mendelian dominant. Thus it is suggested that urgent attempts should be made to assess the hereditability not only of the Simian crease but also other normal crease con- figurations among the anthropoids and Man.

I am greatly indebted to Dr K. C. Malhotra, Director, Dhangar Project, Deccan College for his valuable suggestions and help in preparing this paper. Thanks are also due to Mr Patric F. Dasson for typing the manuscript.

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