Knuckle walking signal in the manual digits of Pan and Gorilla

This article examines the curvature of the manual proximal and middle phalanges of species belonging to Pan, Gorilla, Ateles, Macaca, Pongo, Hylobates, and Cebus to determine whether middle phalangeal curvature, when considered in conjunction with proximal phalangeal curvature, yields a locomotor signal. Prior studies have demonstrated the discriminatory power of proximal phalanges for separating suspensory species (including knuckle walkers) from pronograde quadrupedal species, but less emphasis has been placed on the distinguishing phalangeal characteristics of taxa within the suspensory category. This study demonstrates, first, that middle phalanges discriminate suspensory from nonsuspensory species, although not as cleanly as proximal phalanges. Finer discrimination of locomotor signals, including subtle differences among animals employing different modes of suspension, is possible through a comparison of the curvatures of the proximal phalanges and corresponding middle phalanges. Their relative curvature differs in quadrupeds, brachiators, and knuckle walkers. Knuckle walkers (Pan and Gorilla) have relatively little curvature of the middle phalanges coupled with marked curvature of the proximal phalanges, whereas brachiators (Ateles and Hylobates) display marked curvature of both proximal and middle phalanges, and pronograde quadrupeds (Cebus and Macaca) have relatively straight proximal and moderately curved middle phalanges. Quadrumanous climbers (Pongo) have a unique combination of traits, whereby curvature is high in both proximal and middle phalanges, but less so in the latter than the former. These differences, predictable on the basis of the biomechanical forces to which digits are subjected, may open a new venue for future research on the locomotor repertoire of prebipedal ancestors of hominins.     

从中指骨长度推算身高的研究

作者对近年在华南地区收集的,已知生前身高的汉族成年男性骨骼的中指骨近节、中节进行了测量。用直线回归方程、多元回归方程对从中指骨长度推算身高进行了研究。并用50例国人骨骼标本对这些推算身高的方法作了检验。结果表明,中指骨与四肢大型长骨,以及从中指骨长度推算身高的直线回归方程与多元回归方程,对推算身高的价值都是相同的。     

Trabecular Architecture of the Manual Elements Reflects Locomotor Patterns in Primates

The morphology of trabecular bone has proven sensitive to loading patterns in the long bones and metacarpal heads of primates. It is expected that we should also see differences in the manual digits of primates that practice different methods of locomotion. Primate proximal and middle phalanges are load-bearing elements that are held in different postures and experience different mechanical strains during suspension, quadrupedalism, and knuckle walking. Micro CT scans of the middle phalanx, proximal phalanx and the metacarpal head of the third ray were used to examine the pattern of trabecular orientation in Pan, Gorilla, Pongo, Hylobates and Macaca. Several zones, i.e., the proximal ends of both phalanges and the metacarpal heads, were capable of distinguishing between knuckle-walking, quadrupedal, and suspensory primates. Orientation and shape seem to be the primary distinguishing factors but differences in bone volume, isotropy index, and degree of anisotropy were seen across included taxa. Suspensory primates show primarily proximodistal alignment in all zones, and quadrupeds more palmar-dorsal orientation in several zones. Knuckle walkers are characterized by having proximodistal alignment in the proximal ends of the phalanges and a palmar-dorsal alignment in the distal ends and metacarpal heads. These structural differences may be used to infer locmotor propensities of extinct primate taxa.     

Hominoid phalanges from the middle Miocene site of Paşalar, Turkey

Eleven proximal and ten intermediate partial or complete hominoid phalanges have been recovered from the middle Miocene site of Pa?alar in Turkey. Based on species representation at Pa?alar, it is likely that most or all of the phalanges belong to Griphopithecus alpani rather than Kenyapithecus kizili, but both species may be represented. All of the complete or nearly complete phalanges appear to be manual, so comparisons to extant and other fossil primate species were limited to manual phalanges. Comparisons were made to extant hominoid and cercopithecoid primate genera expressing a variety of positional repertoires and varying degrees of arboreality and terrestriality. The comparisons consisted of a series of bivariate indices derived from previous publications on Miocene catarrhine phalangeal morphology. The proximal phalanges have dorsally expanded proximal articular surfaces, which is characteristic of cercopithecoids and most other Miocene hominoids, and indicates that the predominant positional behaviors involved pronograde quadrupedalism. Among the extant primates, many of the proximal and intermediate phalangeal indices clearly distinguish more habitually terrestrial taxa from those that are predominantly arboreal, and especially from taxa that commonly engage in suspensory activities. For nearly every index, the values of the Pa?alar phalanges occupy an intermediate position-most similar to values for Pan and, to a lesser extent, Macaca-indicating a generalized morphology and probably the use of both arboreal and terrestrial substrates. At least some terrestrial activity is also compatible with reconstructions of the Pa?alar habitat. Most proximal and intermediate phalanges of other middle and late Miocene hominoids have similar index values to those of the Pa?alar specimens, revealing broadly similar manual phalangeal morphology among many Miocene hominoids.     

Functional and morphological affinities of the subadult hand (O.H. 7) from Olduvai Gorge.

Study of the O.H. 7 hand was based primarily on morphological comparisons with a large series of hand skeletons of extant hominoid primates. Most of the hand elements are fragmentary or have missing epiphyses and only comparisons based on qualitative morphological observations are possible. The distal phalanges are complete, however, and were analyzed metrically utilizing univariate and multivariate statistical techniques. To compensate for size differences among the Hominoidea a number of size adjustments were employed. None of the adjustments were totally satisfactory from theoretical and practical standpoints and none completely eliminated the influence of size. There is no entirely satisfactory procedure to eliminate size and it is advisable to use several techniques that are not closely related, to compare the results and interpret them with caution. In certain features the wrist and fingers resemble those of African apes; in others they are more like modern human hands; in still others they are unique. The scaphoid and the proximal articular surface of the trapezium retain ape-like features, as do the proximal and middle phalanges. The pollical carpometacarpal joint and the distal phalanges are closer in morphology to those of modern humans. The scaphoid, proximal phalanges and middle phalanges of rays II-V indicate a hand capable of a strong power grip. A number of features of the thumb and the distal phalanges suggest that the O.H. 7 individual was capable of more precise manipulation that extant apes. FLK NN-A, a first distal phalanx, does not closely resemble the first distal phalanx of any of the living Hominoidea. Multivariate distance analysis indicates, however, that it is closest in overall morphology to the pollical distal phalanx of modern humans. In some features not included in the metric analysis, FLK NN-A also resembles the hallucial distal phalanx of modern humans.     

Metacarpophalangeal pattern profiles in Venezuelan and northern Caucasoid samples compared

Comparison of hand long-bone lengths and variances in published measurements of North American Caucasoid, Venezuelan, and English individuals, and of their metacarpophalangeal pattern profiles (MPP), revealed systematic differences between samples from infancy through adulthood. The variances of Venezuelan males tend to be larger than those of Americans, especially under 9 years of age. The same trend was observed for females, but to a lesser degree. The English sample showed variance similar to that of Venezuelans and Americans. Below 7 years of age, bones of Venezuelans were longer than those of Americans, except the distal phalanges, which always were longer in the latter, as were all bones after age 17. The index finger's middle and distal phalanges of Americans were relatively longer than the other bones at all ages. Females also showed this general trend, though not as clearly. Venezuelan adults had longer first and second metacarpals and proximal phalanges than the English adult homologs. American adults had all bones longer than those of English adults. The English adults showed a "typical" MPP, characterized by shorter proximal phalanges, both when compared with Venezuelan and with American adults. Genetic rather than environmental causes are likely as an explanation for these differences. This warned us against the indiscriminate use of any "standard" sample from a different population to establish objective profile patterns and sizes in abnormal cases, as illustrated with one example.     

Metacarpophalangeal length changes in humans during adulthood: a longitudinal study.

Total lengths of the 19 diaphyseal hand bones were measured from standardized radiographs of healthy American whites as young adults (ca. 21 years) and again at ca. 55 years of age. The four hand-bone rows exhibit distinctive length changes: Distal and middle phalanges continue to increase significantly in length, proximal phalanges constitute a transition zone of little change, and metacarpals uniformly decrease in length. Clear-cut sex differences are noteworthy: Males change more (lose more in some bone rows, gain more in others) than females. Progressive elongation was greatest in the distal phalanges where apposition around the distal aspect ("tufting") is not constrained by a joint or epiphysis. Loss of bone length in the metacarpals by subchondral resorption is consistent with documented reductions in activity levels and grip strength with age, as well as diminished joint spaces which alter loading of the joints.     

Ontogenetic and anatomic variation in mineralization of the wing skeleton of the Mexican free-tailed bat, Tadarida brasiliensis

We examined patterns of variation in the mineral content of the wing skeleton of the Mexican free-tailed bat, Tadarida brasiliensis. We ashed humeri, radii, metacarpals II-V, and phalanges of digit III, and quantified mineralization differences among elements at specific ages, and ontogenetically for each element. The most mineralized elements are the humerus and the radius, followed by the metacarpals, of which the third and fifth are the most mineralized. The proximal and middle phalanges of the third digit exhibit the lowest mineral content, and the distal phalanges have no mineral content according to our ashing protocol. Histological examination shows a thin (< 10 μm) shell of unmineralized osteoid surrounding a cartilaginous core in distal phalanges. Mineral content of each bone increases linearly with age during post-natal development, but there are differences in the rate and extent of this increase among the different elements.
The mineralizaton differences we observed parallel substantially different bone loading patterns found in different parts of the wing in other studies. The humerus and radius are subjected to large torsional loads during flight, while the metacarpals and phalanges experience dorsoventral bending. The high mineral content of the humerus and radius and the low mineral content of the metacarpals and phalanges may resist torsion proximally and promote bending distally. Furthermore, the decrease in mineral content along the wing's proximodistal axis decreases bone mass disproportionately at the wing tips, where the energetic cost of accelerating and decelerating limb mass is greatest.     

Phalangeal morphology of the Paromomyidae (?Primates,Plesiadapiformes): The evidence for gliding behavior reconsidered

A comparative morphometric analysis of isolated proximal and intermediate phalanges attributed to the paromomyids Ignacius graybullianus and Phenacolemur simonsi was undertaken to test the hypothesis that these fossil phalanges exhibit evidence of a dermopteran-like interdigital patagium. Linear dimensions were collected for the fossil phalanges and a comparative sample of associated proximal and intermediate phalanges representing extant tree squirrels, tree shrews, dermopterans (colugos), gliding rodents and marsupials, and prosimian primates. Quantitative data indicate that the proximal and intermediate phalanges of paromomyids are most similar in their overall shape to those of the dermopteran Cynocephalus. The proximal phalanges of paromomyids and colugos possess well-developed flexor sheath ridges and broad, high shafts, whereas the intermediate phalanges of these taxa are most similar to one another in their trochlear morphology. Discriminant analysis indicates that all of the paromomyid intermediate phalanges resemble those from colugo toes more so than those from colugo fingers. Moreover, the relative length and midshaft proportions of both the proximal and intermediate phalanges of paromomyids closely resemble those of several squirrels that lack an interdigital patagium. The following conclusions are drawn from this study: 1) paromomyids share a number of derived phalangeal features with modern dermopterans that may be indicative of a phylogenetic relationship between them, 2) existing intermediate phalanges of paromomyids are inconsistent with the “mitten gliding” hypothesis because they do not possess the distinctive length and midshaft proportions characteristic of colugo manual intermediate phalanges, and 3) paromomyids share with colugos and the scaly-tailed squirrel Anomalurus several aspects of phalangeal morphology functionally related to frequent vertical clinging and climbing on large-diameter arboreal supports. Am J Phys Anthropol 109:397–413, 1999. © 1999 Wiley-Liss, Inc.     

广西侗族手指指毛的分布

本文调查了广西三江侗族18至50岁农民和学生279人(男153、女126)的手指指毛分布。结果说明,近侧和中间指节除发现一例女性没有指毛以外,其余均有指毛,远侧指节无指毛。男女两性间指毛的出现率无明显差异,左右手指指毛分布基本上对称。     

Collateral ligaments of the distal sesamoid bone in the digit of Equus: re-evaluating midstance function

The distal forelimb of the horse has a complex array of ligaments that play a critical role in determining function of the digit and are often associated with the initiation of foot pathologies. The collateral ligaments of the distal sesamoid bone (CLDS) play an important role in digit stabilization near the end of foot contact and there is also limited evidence to suggest that the CLDS stabilize the proximal interphalangeal joint (PIPJ) during weight bearing. By virtue of their anatomical attachments where the ligaments pass dorsal to the axis of rotation of the PIPJ, it is reasonable to assume that the CLDS prevent flexion of the PIPJ during weight bearing or midstance in a moving horse. To test this functional hypothesis, forelimb specimens from three mixed-breed horses were loaded in compression in a materials testing frame. Limb loading was applied with the CLDS intact and following transection. Average PIPJ angle and metacarpophalangeal joint (MCPJ) angle at maximum load (approximately 3000 N) were calculated from angular changes of proximal and middle phalanges and the third metacarpal, which were compared between intact and transected trials. PIPJ angles were found to be the same (175 degrees) at maximum load for intact and transected trials. The proximal and middle phalanges rotated together remaining aligned, regardless of the CLDS condition. Contrary to expectation, however, the combined proximal and middle phalanges unit rotates less relative to the third metacarpal under load after transection, indicating less digit extension at the metacarpophalangeal (fetlock) joint without the influence of CLDS. Since the mechanical properties of the fetlock joint are unchanged by CLDS transection, observed proximal and middle phalanx motion is dependent on increased rotation of the distal phalanx after transection. The original hypothesis was not supported and the results suggest that at midstance the CLDS function primarily to stabilize the articulation of the middle phalanx about the distal phalanx to limit distal interphalangeal joint extension during weight bearing. Establishing the functional role of the CLDS may help to better understand the biomechanical consequences of ligament injuries and diseases of the pastern.     

Metric dimensions of the proximal phalanges of the human hand and their relationship to side, position, and asymmetry

The anatomy of the proximal phalanges of the human hand has been widely described. Nevertheless, when consulting osteology and anatomy publications, the general opinion of researchers is that siding and allocating the proximal phalanges with regard to finger position is difficult, if not impossible. We provide morphological criteria for determining the side of the proximal phalanges and a metric means of allocating a phalanx to a specific finger. This paper also quantifies the absolute and directional asymmetry found in phalanges within this sample. The sample studied consists of three groups, one modern and two archaeological. To investigate these, three measurements were taken—maximum length, maximum width at the base and maximum width at the head. It was found that phalanges could be assigned correctly to the side and finger of origin in 100% of the cases when the five phalanges of a given hand were present, and that this result dropped to 92% when allocating isolated phalanges. The means of the measurements taken were larger in the modern group and a constant relationship between the greater basal width of the second and the fourth proximal phalanges was found.     

Ecomorphology of the cervid intermediate phalanx and its implications for palaeoenvironmental reconstruction

This paper reports on newly developed ecomorphological models for the cervid intermediate phalanx. Using a geometric morphometric approach, we quantitatively assess the overall gracility of the bone, the depth and concavity of the proximal articulation and the roundness and symmetry of the distal articulation in the intermediate phalanx, to establish relationships between morphology, locomotor behavior and environment. The morphology of the phalanx was found to vary along a gradient from gracile phalanges with shallow proximal articulations in forms adapted to yielding substrate, to robust phalanges with deeper proximal articulations in taxa adapted to firm substrate. Phylogeny and allometry are accounted for using regressions and phylogenetic comparative methods. Although the results indicate phylogeny explains part of the morphological variation, overall the shape of the intermediate phalanx appears mainly driven by differences in function. Consequently, this element promises to be a useful palaeoenvironmental proxy that can be applied on fossil assemblages with cervid remains.     

Hand and foot remains from the Gran Dolina Early Pleistocene site (Sierra de Atapuerca, Spain).

We report here the study of the 22 hand and foot remains from the Early Pleistocene level TD6 of the Gran Dolina site at Sierra de Atapuerca (Burgos, Spain) recovered from 1994 to 1996. These remains are paratypes of Homo antecessor. All of the elements are briefly described and compared with other fossil hominids. The capitate has a constricted neck, well developed head, strong attachment for the ligamentum interosseum trapezoid-capitate, a palmarly placed trapezoid facet with a distinctive small dorsal trapezoid facet, a highly curved and oblique orientation of the second metacarpal facet, and a transversally oriented dorsodistal border. A hamate with a moderately projecting and lightly built hamulus; an inferred reduced styloid process on the third metacarpal base; a wide second metacarpal head; and middle phalanges with well marked insertions for the flexor digitorum superficialis muscle and wide heads. The morphology and dimensions of the pedal remains from TD6 are very similar to modern humans; but the base, proximal articular surface and shafts of the proximal hallucal phalanges are more rounded and the midshaft of the proximal toe phalanx is wider.     

Tubular hand bone growth during the latter half of the prenatal period: an allometric analysis

The growth of the 19 tubular hand bones from fetal months 5 to 9 was studied by the allometric method. The hand bones were carefully dissected under a low power stereoscopic microscope. The length and breadth of all bones was found to be monophasic in relation to crown-rump length. In general, maximum bone and ossified shaft lengths in the same row group demonstrate similar allometric coefficients. The specific growth rate of ossified shaft length for all fetal hand bones is greater than the growth rate of maximum length. The highest allometric coefficients for both maximum length and ossified shaft length were obtained from the middle phalanges. The shape of the metacarpals and distal phalanges becomes thinner, while the other bones become thicker or maintain their length-breadth ratio. The relative growth pattern of the first proximal phalanx differed from the middle phalangeal group of the other digits. This suggests that current nomenclatures for the three bones of the pollex is appropriate.     

Development of limbs in urodeles and the origin of tetrapod limbs

On the basis of studies on serial sections of larval Ranodon sibiricus limbs and published data, the hypothesis of the origin of tetrapod limbs from the biserial archipterygium is proposed. The mesomeres of the central axis of the biserial fin correspond (in proximodistal direction) to the humerus, ulna, ulnare, all carpalia distalia, metacarpale 1, and phalanges of the first digit in the forelimb of caudate amphibians and to the femur, fibula, fibulare, tarsalia distalia, metatarsale 1, and phalanges of the first digit in the hind limb. The preaxial elements of the zygopodium and autopodium, which are positioned proximal to the digital arch, correspond to the preaxial rays of the biserial fin, and digits 2–5 correspond to its postaxial rays. As the fin transformed into the limb, the central axis curved preaxially, forming the digital arch and resulting in partial reduction and fusion of preaxial rays.     

Mechanical advantages of the Neanderthal thumb in flexion: a test of an hypothesis

It has been proposed that the pollical phalangeal length proportions of the Neanderthals provided them with a greater mechanical advantage relative to recent humans for their pollical flexor muscles in power grips across the interphalangeal (IP) joint at the expense of the mechanical advantage of those pollical flexor muscles in precision grips at the finger tip. To test these related hypotheses, we compared the pollical load arm dimensions (phalanx lengths) to power arm dimensions (dorsopalmar articular heights) for the European and Near Eastern Neanderthals and for European and Amerindian samples of recent humans. It was found, initially, that the proximal articular height of the pollical distal phalanx is a poor predictor of the power arm at the IP articulation, even though the proximal articular height of the pollical proximal phalanx was an adequate indicator of the power arm size at the metacarpophalangeal (MCP) joint. In addition, differences in distal pollical ulnar deviation at the IP joint appeared to make little difference in the mechanical advantage comparisons. More importantly, the relative shortness of Neanderthal proximal pollical phalanges and the relative lengthening of their distal pollical phalanges was confirmed, and it was determined that, despite some minor differences in articular dimensions between Neanderthals and recent humans, these pollical phalangeal length contrasts translated into significant differences in mechanical advantages for the flexor muscles across the MCP and IP articulations.     

天津蓟州区桃花园墓地明清时期缠足女性的足骨形变

本文通过量化方法,对桃花园墓地明清时期101例女性足骨形变方式、程度、对称性等进行了系统分析。研究结果表明,双侧足骨形变总体上是对称的。缠足对跗骨的影响主要在于整体尺寸缩小和关节面改变。第1跖骨除整体尺寸缩小外,还存在诸多明显的骨体形态改变;第2、3跖骨头部和底部尺寸缩小,但形变不大。第3至第5近节趾骨骨体长度和高度的侧别差异明显,特别是第3近节趾骨双侧整体不对称。该群体至少在18岁时已经缠足,25岁以后足骨已发生形变,35岁之后形变较明显。部分个体足骨形变程度较轻,其生前可能仅束足纤直,未经裹弯。足骨形变程度与陪葬品多寡并无相关性,其形变差异很可能与身体疾病、劳作需要、缠足方法或缠足观念差异有关。     

Principal component analysis of the elongation of metacarpal and phalangeal bones

A hypothesis that the first principal component computed from the covariance matrix of logarithms reflected the specific growth rates of corresponding bones was taken to analyze the growth pattern of the tubular bones of the hand. The total length of 19 tubular bones of the right hand was measured on standardized radiographs of Japanese children (33 boys, 33 girls). Metacarpals in boys and bones of the fifth digit in girls showed higher growth coefficients. The second, third and fourth proximal, and the third and fourth middle phalanges showed lower coefficients for both sexes. These observations suggest the signs of proximal row dominance in boys and of fifth ray dominance in girls in the elongation of the hand bones. A marked sex difference was found in the fifth middle phalanx. In girls the growth coefficients of this bone was much larger than any other bones, but was moderate in boys.     

Notches in the non-epiphyseal ends of the metacarpals and phalanges in children of four South African populations

The incidence of notches in the non-epiphyseal ends of the shafts of the metacarpals and phalanges was determined from radiographs of the left hand of 1,303 Pretoria school-children aged 6 to 11 years. The group included White, Negro, Coloured and Indian children. The notches represent vestiges of supernumerary epiphyses or pseudo-epiphyses. Notching of one or more of the metacarpals or phalanges was found in 88.9% of White children, 77.1% of Negro children, 84.3% of Coloured children and 78.8% of Indian children. Notches were most common in metacarpal I followed in declining order of frequency by metacarpal II, metacarpal V, middle phalanx V and proximal phalanx I. Notches were rare in other sites. The mean number of notches per subject was significantly higher in males than in females in all four population groups. However, the sex differences appear to be due mainly to earlier obliteration of notches in females. The findings in White children suggest that there is no significant relationship between metacarpal and phalangeal notching and skeletal maturation rate. Notches are significantly more common in Pretoria Whites than in relatively poorly nourished Pretoria Negro children. It is concluded that the occurrence of notches is a normal phenomenon accompanying the ossification of the hand skeleton and that notching is related neither to retardation in skeletal development nor to undernutrition.