GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Humans as inverted bats: A comparative approach to the obstetric conundrum
    Wiley ; 2019
    In:  American Journal of Human Biology Vol. 31, No. 2 ( 2019-03)
    Details
    In: American Journal of Human Biology, Wiley, Vol. 31, No. 2 ( 2019-03)
    Abstract: The narrow human birth canal evolved in response to multiple opposing selective forces on the pelvis. These factors cannot be sufficiently disentangled in humans because of the limited range of relevant variation. Here, we outline a comparative strategy to study the evolution of human childbirth and to test existing hypotheses in primates and other mammals. Methods We combined a literature review with comparative analyses of neonatal and female body and brain mass, using three existing datasets. We also present images of bony pelves of a diverse sample of taxa. Results Bats, certain non‐human primates, seals, and most ungulates, including whales, have much larger relative neonatal masses than humans, and they all differ in their anatomical adaptations for childbirth. Bats, as a group, are particularly interesting in this context as they give birth to the relatively largest neonates, and their pelvis is highly dimorphic: Whereas males have a fused symphysis, a ligament bridges a large pubic gap in females. The resulting strong demands on the widened and vulnerable pelvic floor likely are relaxed by roosting head‐down. Conclusions Parturition has constituted a strong selective force in many non‐human placentals. We illustrated how the demands on pelvic morphology resulting from locomotion, pelvic floor stability, childbirth, and perhaps also erectile function in males have been traded off differently in mammals, depending on their locomotion and environment. Exploiting the power of a comparative approach, we present new hypotheses and research directions for resolving the obstetric conundrum in humans.
    Type of Medium: Online Resource
    ISSN: 1042-0533 , 1520-6300
    URL: Issue
    URL: Article
    DOI: 10.1002/ajhb.v31.2
    DOI: 10.1002/ajhb.23227
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 2001218-4
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Evolution of the human birth canal
    Elsevier BV ; 2023
    In:  American Journal of Obstetrics and Gynecology ( 2023-7)
    Details
    In: American Journal of Obstetrics and Gynecology, Elsevier BV, ( 2023-7)
    Type of Medium: Online Resource
    ISSN: 0002-9378
    URL: Article
    DOI: 10.1016/j.ajog.2022.09.010
    RVK:
    XA 19400
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2023
    detail.hit.zdb_id: 2003357-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    The variation in shape and thickness of the pelvic floor musculature in males and females: a geometric-morphometric analysis
    Springer Science and Business Media LLC ; 2023
    In:  International Urogynecology Journal Vol. 34, No. 2 ( 2023-02), p. 453-461
    Details
    In: International Urogynecology Journal, Springer Science and Business Media LLC, Vol. 34, No. 2 ( 2023-02), p. 453-461
    Abstract: In women, the risk of pelvic floor prolapse is known to be associated with age and parity. Different studies suggested that it is also related to pelvic dimensions, e.g. biomechanical modelling showed that a larger pelvic canal results in higher values of displacement, stress and strain in the pelvic floor muscles, which can increase the risk of pelvic floor disorders. To better understand the multiple factors contributing to pelvic floor disorders, we assessed how age, body weight, body height, parity (in women), pelvic canal size and overall muscle development affected pelvic floor geometry. Methods A comprehensive geometric morphometric analysis of variation in pelvic floor muscle shape was conducted based on a dense set of 3D landmarks measured on CT scans in a cohort of 49 deceased men and 52 deceased women. The multivariate association between biological variables (parity, dimensions of the true pelvis, age, body weight, height) and pelvic floor muscle morphology was explored by reduced rank regression in both sexes. Results In women, advanced age, high body weight relative to body height and a large pelvic canal were associated with a deeper pelvic floor. Surprisingly, parity did not have any strong association with overall pelvic floor shape. In men, high body weight was associated with a deep pelvic floor. Age had little effect on male pelvic floor shape, except for the thickness of the ischiocavernosus muscle, which reduced with age. Conclusion These results suggest that age, relative body weight and the size of the pelvic canal contribute to the risk of female pelvic floor disorders via their effect on pelvic floor shape, independently of birth-related factors such as injury and avulsion of pelvic floor muscles.
    Type of Medium: Online Resource
    ISSN: 0937-3462 , 1433-3023
    URL: Article
    DOI: 10.1007/s00192-022-05311-5
    RVK:
    XA 50350
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 1481561-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Allometry and Sexual Dimorphism in the Human Pelvis
    Wiley ; 2017
    In:  The Anatomical Record Vol. 300, No. 4 ( 2017-04), p. 698-705
    Details
    In: The Anatomical Record, Wiley, Vol. 300, No. 4 ( 2017-04), p. 698-705
    Abstract: Sexual dimorphism in the human pelvis has evolved in response to several jointly acting selection regimes that result from the pelvis’ multiple roles in locomotion and childbirth, among others. Because human males are, on average, taller than females, some aspects of sexual dimorphism in pelvis shape might result from allometry, the association between stature and pelvis shape across individuals. In this study, they aimed to disentangle and quantify the two components contributing to pelvic sex differences: the allometric component, which emerges as a consequence of dimorphism in stature, and the remaining non‐allometric sexual dimorphism component. A geometric morphometric analysis of a dense set of 3D landmarks, measured on 99 female and male adult individuals was conducted. While pelvis size was similar in both sexes, the average differences in pelvis shape reflected the well‐documented pattern of sexual dimorphism. There was almost no overlap between females and males in shape space. Their analysis showed that pelvis size and shape were similarly associated with stature in both sexes. It was found that dimorphism in the height‐to‐width ratio of the pelvis and in the orientation of the iliac blades was largely allometric, whereas dimorphism in the subpubic angle and the relative size and distance of the acetabula was largely non‐allometric. It was concluded that, in contrast to the overall pelvic proportions, sexual dimorphism in the birth‐relevant pelvic dimensions was mainly of non‐allometric origin and was presumably mediated via steroid hormone secretion during puberty. Anat Rec, 300:698–705, 2017. © 2017 Wiley Periodicals, Inc.
    Type of Medium: Online Resource
    ISSN: 1932-8486 , 1932-8494
    URL: Issue
    URL: Article
    DOI: 10.1002/ar.v300.4
    DOI: 10.1002/ar.23549
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 2273240-8
    detail.hit.zdb_id: 2109216-3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    The evolution of pelvic canal shape and rotational birth in humans
    Springer Science and Business Media LLC ; 2021
    In:  BMC Biology Vol. 19, No. 1 ( 2021-10-11)
    Details
    In: BMC Biology, Springer Science and Business Media LLC, Vol. 19, No. 1 ( 2021-10-11)
    Abstract: The human foetus typically needs to rotate when passing through the tight birth canal because of the complex shape of the pelvis. In most women, the upper part, or inlet, of the birth canal has a round or mediolaterally oval shape, which is considered ideal for parturition, but it is unknown why the lower part of the birth canal has a pronounced anteroposteriorly oval shape. Results Here, we show that the shape of the lower birth canal affects the ability of the pelvic floor to resist the pressure exerted by the abdominal organs and the foetus. Based on a series of finite element analyses, we found that the highest deformation, stress, and strain occur in pelvic floors with a circular or mediolaterally oval shape, whereas an anteroposterior elongation increases pelvic floor stability. Conclusions This suggests that the anteroposterior oval outlet shape is an evolutionary adaptation for pelvic floor support. For the pelvic inlet, by contrast, it has long been assumed that the mediolateral dimension is constrained by the efficiency of upright locomotion. But we argue that the mediolateral elongation has evolved because of the limits on the anteroposterior diameter imposed by upright posture. We show that an anteroposteriorly deeper inlet would require greater pelvic tilt and lumbar lordosis, which compromises spine health and the stability of upright posture. These different requirements of the pelvic inlet and outlet likely have led to the complex shape of the pelvic canal and to the evolution of rotational birth characteristic of humans.
    Type of Medium: Online Resource
    ISSN: 1741-7007
    URL: Article
    DOI: 10.1186/s12915-021-01150-w
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2133020-7
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Reply to Grossman: The role of natural selection for the increase of Caesarean section rates
    Proceedings of the National Academy of Sciences ; 2017
    In:  Proceedings of the National Academy of Sciences Vol. 114, No. 8 ( 2017-02-21)
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 114, No. 8 ( 2017-02-21)
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1621176114
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2017
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Covariation between human pelvis shape, stature, and head size alleviates the obstetric dilemma
    Proceedings of the National Academy of Sciences ; 2015
    In:  Proceedings of the National Academy of Sciences Vol. 112, No. 18 ( 2015-05-05), p. 5655-5660
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 112, No. 18 ( 2015-05-05), p. 5655-5660
    Abstract: Compared with other primates, childbirth is remarkably difficult in humans because the head of a human neonate is large relative to the birth-relevant dimensions of the maternal pelvis. It seems puzzling that females have not evolved wider pelvises despite the high maternal mortality and morbidity risk connected to childbirth. Despite this seeming lack of change in average pelvic morphology, we show that humans have evolved a complex link between pelvis shape, stature, and head circumference that was not recognized before. The identified covariance patterns contribute to ameliorate the “obstetric dilemma.” Females with a large head, who are likely to give birth to neonates with a large head, possess birth canals that are shaped to better accommodate large-headed neonates. Short females with an increased risk of cephalopelvic mismatch possess a rounder inlet, which is beneficial for obstetrics. We suggest that these covariances have evolved by the strong correlational selection resulting from childbirth. Although males are not subject to obstetric selection, they also show part of these association patterns, indicating a genetic–developmental origin of integration.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1420325112
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2015
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Reply to Underdown and Oppenheimer: Roles of selection, plasticity, and genetics in the integration of human pelvis shape and head size
    Proceedings of the National Academy of Sciences ; 2016
    In:  Proceedings of the National Academy of Sciences Vol. 113, No. 3 ( 2016-01-19)
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 113, No. 3 ( 2016-01-19)
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1520865113
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2016
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Cliff-edge model of obstetric selection in humans
    Proceedings of the National Academy of Sciences ; 2016
    In:  Proceedings of the National Academy of Sciences Vol. 113, No. 51 ( 2016-12-20), p. 14680-14685
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 113, No. 51 ( 2016-12-20), p. 14680-14685
    Abstract: The strikingly high incidence of obstructed labor due to the disproportion of fetal size and the mother’s pelvic dimensions has puzzled evolutionary scientists for decades. Here we propose that these high rates are a direct consequence of the distinct characteristics of human obstetric selection. Neonatal size relative to the birth-relevant maternal dimensions is highly variable and positively associated with reproductive success until it reaches a critical value, beyond which natural delivery becomes impossible. As a consequence, the symmetric phenotype distribution cannot match the highly asymmetric, cliff-edged fitness distribution well: The optimal phenotype distribution that maximizes population mean fitness entails a fraction of individuals falling beyond the “fitness edge” (i.e., those with fetopelvic disproportion). Using a simple mathematical model, we show that weak directional selection for a large neonate, a narrow pelvic canal, or both is sufficient to account for the considerable incidence of fetopelvic disproportion. Based on this model, we predict that the regular use of Caesarean sections throughout the last decades has led to an evolutionary increase of fetopelvic disproportion rates by 10 to 20%.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1612410113
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2016
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    Sex differences in the pelvis did not evolve de novo in modern humans
    Springer Science and Business Media LLC ; 2021
    In:  Nature Ecology & Evolution Vol. 5, No. 5 ( 2021-03-25), p. 625-630
    Details
    In: Nature Ecology & Evolution, Springer Science and Business Media LLC, Vol. 5, No. 5 ( 2021-03-25), p. 625-630
    Type of Medium: Online Resource
    ISSN: 2397-334X
    URL: Article
    DOI: 10.1038/s41559-021-01425-z
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2879715-2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...