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1.
Various constructed ridge count phenotypes were studied in two endogamous populations from peninsular India. Heritabilities were estimated for five summed pattern ridge count traits: fingers and toes together; palms and soles together; fingers and palms together (manus); toes and soles together (pes); and fingers, palms, toes and soles together, defined as the total ridge count in man. In general, these phenotypes were found to he highly heritable, with the summed ridge counts for fingers and toes, and total ridge count showing almost Complete determination by additive polygenes. Total manus and pes pattern counts are less heritable. Little or no uterine environmental effects were detected for any of these phenotypes.  相似文献   

2.
The geometrical characteristics of the fore claw toes of mole rats Scaptochirus moschatus were analyzed. It was found that the middle three toes play the major role in soil-cutting performance. So the middle three toes were selected as the prototype for designing the biomimetic specimens. The biomimetic specimens were manufactured using reverse engineering and rapid prototype technology. The scales of the second toe (one of the middle three toes) and the angle between the back side and the palm side of the second toe were taken as the main geometrical structure parameters for designing the comparative specimen. The horizontal soil-cutting tests were conducted to examine the effects of the biomimetic geometrical structure on the soil-cutting resistance. The results show that the resistance of the biomimetic specimen is 12.80% smaller than the comparative specimen, which indicates that the toe geometry has a significant effect on its soil-cutting performance. The investigation into the effect of toe arrangement suggests that the tip positions of the middle three toes in arc curve arrangement is helpful to reduce soil-cutting resistance.  相似文献   

3.
Human hands and feet have longer, more robust first digits, and shorter lateral digits compared to African apes. These similarities are often assumed to be independently evolved adaptations for manipulative activities and bipedalism, respectively. However, hands and feet are serially homologous structures that share virtually identical developmental blueprints, raising the possibility that digital proportions coevolved in human hands and feet because of underlying developmental linkages that increase phenotypic covariation between them. Here we show that phenotypic covariation between serially homologous fingers and toes in Homo and Pan is not only higher than expected, it also causes these digits to evolve along highly parallel trajectories under episodes of simulated directional selection, even when selection pressures push their means in divergent directions. Further, our estimates of the selection pressures required to produce humanlike fingers and toes from an African ape‐like ancestor indicate that selection on the toes was substantially stronger, and likely led to parallel phenotypic changes in the hands. Our data support the hypothesis that human hands and feet coevolved, and suggest that the evolution of long robust big toes and short lateral toes for bipedalism led to changes in hominin fingers that may have facilitated the emergence of stone tool technology.  相似文献   

4.
As great morphological variability characterizes the phalanges of the human toes in adults, we hypothesized for a possible variability in the presence or absence of their secondary (= epiphyseal) centers of ossification linked to the unique morphology of the human foot within primates. The aim of this study was thus to provide original and detailed data on the occurrence of these centers. Classically, the big toe or hallux (I) presents two secondary centers and the lateral toes (II-V) three centers, and consequently the five toes present a total of 14 secondary centers. The material studied consisted of 261 foot radiographs from 261 young individuals of European origin (202 males and 59 females; 6-16 years). The presence (or absence) of the secondary centers of the phalanges of the toes was assessed for each foot. Feet presenting a biphalangeal variant in one or more lateral toes were studied separately. The theoretical possibilities of association of the three secondary centers in a given lateral toe (II-V) are eight in number; these eight patterns were studied and coded in the present study by types A-H. An exceptional variability in the occurrence of the secondary centers in lateral toes (II-V) was observed, and the classic pattern of phalangeal ossification was never observed. The absence of one or more secondary centers seems to be observed only in the human species, and we suggest that this could be a derived pattern specific to the human species, i.e., autapomorphic pattern. These results are of interest in the characterization and understanding of the reduction in size of the lateral toes which characterizes the specific evolution of the human foot.  相似文献   

5.
Age-related features of spinal inhibition in the regulation of voluntary movements in men were studied. It was found that presynaptic and nonreciprocal and reciprocal inhibitions of the flexor of toes during voluntary movements were less intense than inhibition during relative muscle rest in subjects of all age groups. This results from the age-related features of supraspinal excitatory and inhibitory effects on Ia and Ib spinal interneurons, which change the mechanism of spinal inhibition of voluntary movements as the organism develops. In boys 9–12 years of age, execution of voluntary movements is accompanied by the lowest presynaptic inhibition of Ia afferents and the most pronounced increase in nonreciprocal and reciprocal inhibition of α-motoneurons in the flexor of toes, compared to the other age groups. Execution of voluntary movements by boys 14–15 years of age leads to an increase in presynaptic inhibition of Ia afferents and the most pronounced decrease in reciprocal and nonreciprocal inhibition of spinal α-motoneurons of the flexor of toes. By the age of 17–18 years, the mechanism of nonreciprocal inhibition of α-motoneurons of the flexor of toes during voluntary movements is similar to that in adolescents aged 14–15 years. The definitive level of presynaptic inhibition of Ia afferents and reciprocal inhibition of α-motoneurons of the flexor of toes during voluntary movements is reached by 17–18 years.  相似文献   

6.
When quail or chick leg bud mesoderm was grafted to a chick wing bud, toes developed from grafts placed in direct contact with the wing apical ridge. The toes were primarily derived from quail leg cells, with variable participation of host wing cells. Donor cells also integrated into wing-specific structures, such as cartilage of the wing digits and the surrounding connective tissues. In addition to forming toes, the grafted leg mesoderm expressed its leg origin by enlarging skeletal elements in the host wing. In all cases, enlargements were derived of both quail donor and chick host cells, and were not the result of the addition of mass to the host bud. Grafts placed further than 162 microns from the ridge formed neither toes nor enlargements; rather, they integrated into wing-specific structures. Under the influence of the apical ridge, the grafted leg mesoderm cells are able to maintain their leg character and to form toes and skeletal enlargements. Grafts outside the range of ridge influence (162 microns) are affected by their surroundings to integrate into wing-specific structures. The formation of leg-specific structures by leg bud mesoderm grafted to the wing bud has been used to support the principle of nonequivalence, which states that, because of their different developmental histories, wing and leg cells are restricted to form structures specific for their respective limbs. However, we have shown that leg cells can form wing-specific structures, and therefore limb cells are not restricted in their development.  相似文献   

7.
The skin of the foot provides the interface between the bird and the substrate. The foot morphology involves the bone shape and the integument that is in contact with the substrate. The podotheca is a layer of keratinized epidermis forming scales that extends from the tarsometatarsus to the toe extremities. It varies in size, shape, amount of overlap and interacts with the degree of fusion of the toes (syndactyly). A study of toe shape and the podotheca provides insights on the adaptations of perching birds. Our analysis is based on micro‐CT scans and scanning electron microscopy images of 21 species from 17 families, and includes examples with different orientations of the toes: zygodactyl (toes II and III forward), anisodactyl (toes II, III, and IV forward), and heterodactyl (toes III and IV forward). We show that in these three groups, the skin forms part of a perching adaptation that involves syndactyly to different degrees. However, syndactyly does not occur in Psittacidae that use their toes also for food manipulation. The syndactyly increases the sole surface and may reinforce adherence with the substrate. Scale shape and toe orientation are involved in functional adaptations to perch. Thus, both bone and skin features combine to form a pincer‐like foot.  相似文献   

8.
Relative lengths of fingers and toes in human males and females   总被引:17,自引:0,他引:17  
Digital scans of the hands and feet were obtained from 62 heterosexual females and 60 heterosexual males. Scans only of the hands were obtained from 29 homosexual females and 35 homosexual males. The lengths of the individual fingers and toes were estimated from those images by two experienced judges, and length ratios were constructed for all possible pairs of fingers (or toes) on each hand (or foot). Thumbs were not measured, but the great toe was measured and used to construct length ratios. Past research had concentrated on the relative lengths of the index and ring fingers (the 2D:4D ratio). This ratio is close to 1.0 in females and smaller than 1.0 in males. Here 2D:4D did exhibit the largest sex difference, for both hands, followed by 2D:5D and 3D:4D. The sex differences were larger for the right hand than for the left. For both homosexual females and homosexual males, nearly all of the length ratios for fingers were intermediate to those for heterosexual females and heterosexual males; that is, the ratios of homosexual females were masculinized and those of homosexual males were hypomasculinized, but few of these differences were significant. Because many toes were substantially arched, acceptable estimates of length often could not be obtained from the two-dimensional scans, meaning that conclusions about toes are much less certain than those for fingers. Nevertheless, the length ratios were generally larger for toes than for fingers, and the sex differences were generally smaller for toes.  相似文献   

9.
Reconstruction for polysyndactyly of the toes aims at cosmetic improvement. A previous method that uses a skin graft has inherent disadvantages of mismatched pigmentation between the graft and the surrounding skin and scar formation at the donor site. The authors' new improved surgical technique for the treatment of polysyndactyly of the toes does not require a skin graft and therefore avoids these problems. The authors designed a subcutaneous flap from the distal portion of a rectangular flap of skin from the dorsal side of the interdigital webbing and moved the former flap to the sidewall of the base of a toe. Both flaps are the same size; therefore, an interdigital space had to be of sufficient size to accommodate both of them. To ensure an adequate blood supply to the flap, careful handling of the subcutaneous flap is essential for success. This procedure can apply to polysyndactyly of the fourth, fifth, and sixth toes when the fourth and fifth toes adhere over the distal side of the distal interphalangeal joint and when the skin on the dorsal side of the fifth toe, regarded as the excessive one, is at lease twice the size of the dorsal rectangular flap. Ten patients with polysyndactyly of the toe were treated with this method. Aesthetically good results were obtained.  相似文献   

10.
张雷  梁琍  冉辉  沈正雄 《动物学杂志》2012,47(4):135-138
报道了角蟾科一新亚种,该亚种具角蟾属特征,与峨眉角蟾种组中的炳灵角蟾(Megophrysbinlingensis)形态特征最为相近,但与该组成员又有明显区别,被命名为炳灵角蟾梵净山亚种(M.b.fanjingmontis subsp.nov.)。本亚种主要鉴别特征为犁骨棱较弱,后端无犁骨齿,上颌有细齿;第一、二指上婚刺细密,趾侧缘膜窄;体腹面斑少,两侧黑褐色长形斑明显;体型较大,雄性头体长大于60.00 mm;趾间具1/3蹼。  相似文献   

11.
P Ruthnum  J L Tolmie 《Teratology》1987,36(3):299-301
We report a dysmorphic female infant whose mother took warfarin in therapeutic doses during the first 6 weeks of pregnancy. At birth the infant was small for dates and had a triangular facial appearance, micrognathia, microglossia, short fingers and toes, and hypoplastic nails. A skeletal survey revealed hypoplastic distal phalanges in the fingers and toes; there was no epiphyseal stippling. The pattern of malformations present in this infant may either represent the earliest teratogenic effects of warfarin or the fortuitous association of exposure to warfarin and unexplained dysmorphic features.  相似文献   

12.
Some recommendations suggest keeping the shank as vertical as possible during the barbell squat, thus keeping the knees from moving past the toes. This study examined joint kinetics occurring when forward displacement of the knees is restricted vs. when such movement is not restricted. Seven weight-trained men (mean +/- SD; age = 27.9 +/- 5.2 years) were videotaped while performing 2 variations of parallel barbell squats (barbell load = body weight). Either the knees were permitted to move anteriorly past the toes (unrestricted) or a wooden barrier prevented the knees from moving anteriorly past the toes (restricted). Differences resulted between static knee and hip torques for both types of squat as well as when both squat variations were compared with each other (p < 0.05). For the unrestricted squat, knee torque (N.m; mean +/- SD) = 150.1 +/- 50.8 and hip torque = 28.2 +/- 65.0. For the restricted squat, knee torque = 117.3 +/- 34.2 and hip torque = 302.7 +/- 71.2. Restricted squats also produced more anterior lean of the trunk and shank and a greater internal angle at the knees and ankles. The squat technique used can affect the distribution of forces between the knees and hips and on the kinematic properties of the exercise. PRACTICAL APPLICATIONS: Although restricting forward movement of the knees may minimize stress on the knees, it is likely that forces are inappropriately transferred to the hips and low-back region. Thus, appropriate joint loading during this exercise may require the knees to move slightly past the toes.  相似文献   

13.
目的:探讨胎儿肢体畸形超声特征及诊断价值。方法:采用连续顺序追踪法对66342 例妊娠12-40 周孕妇行胎儿四肢畸形筛查。将产前超声诊断结果与引产或产后结果进行对比分析。结果:发生肢体畸形271 例,发生率为0.41 %(271/66342),包括四肢短小5 例,桡骨发育不全1 例,缺肢畸形5 例,足内翻17 例,手掌畸形3 例,指趾畸形222 例及骨骼多发畸形18 例。其中产前诊断胎儿肢体畸形49 例;漏诊222 例,包括:足内翻3 例、指趾畸形218 例、多发骨骼畸形1 例。胎儿肢体畸形的出现率和产前检出率分别为:四肢短小1.84 %(5/271)、100 %(5/5);桡骨发育不全0.36 %(1/271)、100 %(1/1);缺肢畸形1.84 %(5/271)、100 %(5/5);足内翻6.27 %(17/271)、82.35 %(14/17);手掌畸形1.10 %(3/271)、100 %(3/3);指趾畸形81.91 %(222/217)、1. 8%(4/222);多发骨骼畸形6.64 %(18/271)、94.44 %(17/18)。结论:超声对胎儿手掌、脚掌部位以上畸形的检出率较高。指趾畸形出现率最高,但检出率最低。  相似文献   

14.
Noting that some ground-dwelling passerine birds have remarkably long claws, reflected in such names as longclaw (Motacillidae) and longspur (Emberizidae), this comparative study assessed whether these features might aid movement over grassy ground vegetation. Using measurements of museum specimens, we found that, corrected for body size, larks (Alaudidae) living in grassy habitats ( n =31) had significantly longer toes and claws and hence larger footspans than species dwelling on bare substrates ( n =25). Using phylogenetically corrected contrasts, the claw result remained strongly significant, and the footspan result marginally significant, while there was no significant difference between the toes of the two groups. Among 15 matched pairs of other ground-dwelling passerines, where one member of the pair inhabits vegetated ground and the other inhabits bare ground, the former had significantly longer toes and claws and hence larger footspans. We conclude that ground-dwelling passerines living on vegetated, typically grassy ground, have larger feet, due to both longer toes and claws. This probably facilitates movement over uneven and unstable vegetation.  相似文献   

15.
The rotifer fauna has been investigated at three littoral brackish water localities in the Öresund, Denmark. Samples taken from plankton, periphyton and psammon yielded 14 rotifer species. Two of these are new to science and are described herein. Both species were found in psammon at the same locality. Erignatha longidentata n. sp. is characterised by having toes with swollen bases, convex outer margins and concave inner margins. The trophi have a pair of large subunci and relatively large unci. The other new species, Paradicranophorus wesenberglundi n. sp., is characterised by having two large red pigmented eyespots and large conical toes. The rami are lyrate, and intramallei and supramanubria are present in the mallei.  相似文献   

16.
K Fujikura  S Inoue 《Jikken dobutsu》1985,34(4):445-458
The regenerative capacity of hindlimb of Xenopus laevis was investigated by amputating the limbs at four levels in various developmental stages including younger postmetamorphosed froglets. Amputations of limbs were performed at the base of limb in stages 50, 51, 52, 53, 54, 55, 58, and 60 (Nieuwkoop and Faber's table), at the middle of limb bud in stages 50, 51, 52 and 54, and at mid-thigh and mid-shank in stages 58 and 60, and the froglets in 2 and 3 cm in snout-vent length. In the present experiments the regenerative capacity of limbs was expressed by the rate of regeneration and morphogenesis. Tadpoles in the stages after 55 failed to regenerate when the limbs were amputated at base level, but individuals in all the other experimental series exhibited regeneration in various rates irrespective of the level of amputation and the stage. The regenerative capacity increased distally along the proximo-distal axis of the limb when amputated at the same stage, while regeneration was better in younger stages than that in older stages when amputations were made at the same levels. The regenerates obtained by amputation of limbs in stages between 50 and 54, were mainly digitated in that they had 5 toes with 3 claws which is the same pattern with the normal limb, 4 toes with 2 claws, 3 toes with 2 claws or one, and 2 toes with one claw etc. Tadpoles at stage 50 could regenerate toes and claws without defect, but in the later the regenerative capacity gradually declined by reducing the number of toes and claws and accompanied by malformation of skeleton as the stage proceeded. The tadpoles in stages after 58, and the froglets of 2 and 3 cm, produced various types of heteromorphic regenerates of shapes such as cone, spike or rod of which the centra were occupied with cartilage rods. However these regenerates showed no morphological differences according to the developmental stages. These heteromorphic regenerates continued their growth even after one year without any sign of development of digitated feet.  相似文献   

17.
A new species, Leptolalax laui sp. nov. is described based on specimens collected from Hong Kong and Shenzhen City, Guangdong Province, China. The new species can be distinguished from other known congeners by morphological and molecular data. The new species is characterized by the following characters: 1) small size (adult males SVL 24.8.1 mm-26.7 mm); 2) near immaculate creamy white chest and belly; 3) broad lateral fringes on toes; 4) head longer or as long as wide; 5) distinct dark brown spots in flank; 6) moderate dermal fringes on fingers; 7) brown or reddish-brown dorsum with fine round scattered tubercles; 8) thin traverse brownish-grey bars on the dorsal surface of tibia and lower arms; 9) longitudinal ridges under toes not interrupted at the articulations.  相似文献   

18.
Among 1,605 Solomon Islanders from four tribes, there was no sex difference in relative length of the first and second toes. In three of the tribes, longer first toes were slightly more frequent in persons over the age of 45. The percentages of longer first toes in the groups as a whole were 60.5% for Baegu, 66.4% for Nasioi, and 72.1% for Kwaio. These frequencies, resembling those reported for white Americans, Europeans, and single small samples of New Caledonians and Vietnamese, were much below those for Africans. The fourth tribe, the Lau, had only 37.1% with a longer first toe, the lowest percentage reproted so far around the world. No simple mode of single-gene inheritance was apparent, and polygenic inheritance is proposed.  相似文献   

19.
Toe clipping is widely used to permanently mark many species of small vertebrates including marsupials, particularly didelphids and dasyurids. Small marsupials are marked as juveniles, by removing the tip of developing toe buds. It has recently been shown that survival and/or recapture probability decreases with increasing number of toes clipped in frogs. Because of this and other animal welfare concerns, toe clipping of adult vertebrates is increasingly being discouraged. The short‐ and long‐term effects of toe‐bud clipping have not been evaluated in marsupials. We used an experiment to test if marking more toes results in slower growth or higher mortality in the brown antechinus (Antechinus stuartii, Dasyuridae) in the short or long term. We found no harmful effects of toe‐bud clipping. There were no infections associated with clipping, marking more toes did not reduce growth in young or adults, and did not affect survival of young in captivity, survival of independent animals in the wild, or recapture probability. Toe‐bud clipping is done at an extremely immature stage, when the area cut is tiny and perception and memory of pain is unlikely to be a problem. We suggest that toe‐bud clipping is a humane and benign method of permanently marking antechinuses, and probably also the young of other morphologically similar small marsupials.  相似文献   

20.
P Poldre  W Pruzanski  H M Chiu  D A Dotten 《CMAJ》1985,132(3):261-263
Fulminant gangrene of the fingers, toes and nose developed in a 57-year-old woman with Escherichia coli pneumonia. Cryoglobulinemia was noted, and the cryoglobulin was identified as IgM-IgG with anti-I cold agglutinin activity. The cold agglutinins possessed potent lymphocytotoxic and monocytotoxic activity and weaker granulocytotoxic activity. Treatment with plasmapheresis, steroids and antibiotics led to complete clinical recovery, although amputation of several toes was necessary. The patient died 1 1/2 years later; the main findings at autopsy were chronic and acute pyelonephritis and acute bacterial endocarditis. This seems to be the first case of IgM-IgG cold agglutinemia occurring during the course of E. coli infection and the third case of fulminant gangrene complicating transient cold agglutinemia.  相似文献   

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