Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Fetal load and the evolution of lumbar lordosis in bipedal hominins

A Corrigendum to this article was published on 30 May 2012

Abstract

As predicted by Darwin1, bipedal posture and locomotion are key distinguishing features of the earliest known hominins2,3. Hominin axial skeletons show many derived adaptations for bipedalism, including an elongated lumbar region, both in the number of vertebrae and their lengths, as well as a marked posterior concavity of wedged lumbar vertebrae, known as a lordosis4,5,6. The lordosis stabilizes the upper body over the lower limbs in bipeds by positioning the trunk’s centre of mass (COM) above the hips. However, bipedalism poses a unique challenge to pregnant females because the changing body shape and the extra mass associated with pregnancy shift the trunk’s COM anterior to the hips. Here we show that human females have evolved a derived curvature and reinforcement of the lumbar vertebrae to compensate for this bipedal obstetric load. Similarly dimorphic morphologies in fossil vertebrae of Australopithecus suggest that this adaptation to fetal load preceded the evolution of Homo.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: COM and lumbar lordosis during pregnancy.
Figure 2: Maternal COM and lumbar lordosis relative to fetal load.
Figure 3: Sex differences in the lumbar vertebral column of human males and females.
Figure 4: Australopithecine lumbar lordosis and prezygapophyseal angle.

Similar content being viewed by others

References

  1. Darwin, C. The Descent of Man (John Murray, London, 1871)

    Google Scholar 

  2. Galik, K. et al. External and internal morphology of the BAR 1002′00 Orrorin tugenensis femur. Science 305, 1450–1453 (2004)

    Article  CAS  ADS  Google Scholar 

  3. Zollikofer, C. P. E. et al. Virtual cranial reconstruction of Sahelanthropus tchadensis . Nature 434, 755–759 (2005)

    Article  CAS  ADS  Google Scholar 

  4. Robinson, J. T. Early Hominid Posture and Locomotion (Univ. of Chicago Press, Chicago, 1972)

    Google Scholar 

  5. Sanders, W. J. Comparative morphometric study of the australopithecine vertebral series Stw-H8/H41. J. Hum. Evol. 34, 249–302 (1998)

    Article  CAS  Google Scholar 

  6. Latimer, B. & Ward, C. V. in The Nariokotome Homo erectus Skeleton (eds Walker, A. & Leakey, R.) 266–293 (Harvard Univ. Press, Cambridge, MA, 1993)

    Google Scholar 

  7. Strassmann, B. I. The biology of menstruation in Homo sapiens: total lifetime menses, fecundity, and nonsynchrony in a natural-fertility population. Curr. Anthropol. 38, 123–129 (1997)

    Article  Google Scholar 

  8. Jensen, R. K., Doucet, S. & Treitz, T. Changes in segment mass and mass distribution during pregnancy. J. Biomech. 29, 251–256 (1996)

    Article  CAS  Google Scholar 

  9. White, A. A. & Punjabi, M. M. Clinical Biomechanics of the Spine (Lippincott, Philadelphia, 1990)

    Google Scholar 

  10. Bogduk, N. Clinical Anatomy of the Lumbar Spine and Sacrum (Churchill Livingstone, New York, 1997)

    Google Scholar 

  11. Ostgaard, H. C., Andersson, G. B. J., Schultz, A. B. & Miller, J. A. A. Influence of some biomechanical factors on low-back pain in pregnancy. Spine 18, 61–65 (1993)

    Article  CAS  Google Scholar 

  12. Dumas, G. A., Reid, J. G., Griffin, M. P. & McGrath, M. J. Exercise, posture, and back pain during pregnancy. Part 1. Exercise and posture. Clin. Biomech. 10, 98–103 (1995)

    Article  CAS  Google Scholar 

  13. Pal, G. P. & Routal, R. V. Transmission of weight through the lower thoracic and lumbar regions of the vertebral column in man. J. Anat. 152, 93–105 (1987)

    CAS  PubMed  PubMed Central  Google Scholar 

  14. Adams, M. A. & Hutton, W. C. The effect of posture on the role of the apophyseal joints in resisting intervertebral compressive forces. J. Bone Joint Surg. Br. 62, 358–362 (1980)

    Article  CAS  Google Scholar 

  15. Lorenz, M., Patwardhan, A. & Vanderby, R. Load-bearing characteristics of lumbar facets in normal and surgically altered spinal segments. Spine 8, 122–130 (1983)

    Article  CAS  Google Scholar 

  16. Dunlop, R. B., Adams, M. A. & Hutton, W. C. Disc space narrowing and the lumbar facet joints. J. Bone Joint Surg. Br. 66, 706–710 (1984)

    Article  CAS  Google Scholar 

  17. Lee, D. R., Kuehl, T. J. & Eichberg, J. W. Real-time ultrasonography as a clinical and management tool to monitor pregnancy in a chimpanzee breeding colony. Am. J. Primatol. 24, 289–294 (1991)

    Article  Google Scholar 

  18. DeSilva, J. & Lesnik, J. Chimpanzee neonatal brain size: Implications for brain growth in Homo erectus . J. Hum. Evol. 51, 207–212 (2006)

    Article  Google Scholar 

  19. Institute of Medicine of the National Academies. Nutrition During Pregnancy. Part 1. Weight Gain (National Academy Press, Washington DC, 1990)

  20. Alexander, G. R., Himes, J. H., Kaufman, R. B., Mor, J. & Kogan, M. A United States national reference for fetal growth. Obstet. Gynecol. 87, 163–168 (1996)

    Article  CAS  Google Scholar 

  21. Washburn, S. L. Sex differences in the pubic bone. Am. J. Phys. Anthropol. 6, 199–207 (1948)

    Article  CAS  Google Scholar 

  22. Schultz, A. H. Sex differences in the pelves of primates. Am. J. Phys. Anthropol. 7, 401–423 (1949)

    Article  CAS  Google Scholar 

  23. Rosenberg, K. & Trevathan, W. Bipedalism and human birth: The obstetrical dilemma revisited. Evol. Anthropol. 4, 161–168 (1996)

    Article  Google Scholar 

  24. Arensburg, B. in Le Squelette Mousterien de Kebara 2 (eds Bar Yosef, O. & Vandermeersch, B.) 113–146 (Cahiers de Paléoanthropologie, Paris, 1991)

    Google Scholar 

  25. Trinkaus, E. The Shanidar Neandertals (Academic, New York, 1983)

    Google Scholar 

  26. Jungers, W. L. Relative joint size and hominoid locomotor adaptations with implications for the evolution of hominid bipedalism. J. Hum. Evol. 17, 247–265 (1988)

    Article  Google Scholar 

  27. Ruff, C. B. in Primate Locomotion: Recent Advances (eds Strasser, E., Fleagle, J., Rosenberger, A. & McHenry, M.) 449–469 (Plenum, New York, 1998)

    Book  Google Scholar 

  28. Bramble, D. M. & Lieberman, D. E. Endurance running and the evolution of Homo . Nature 432, 345–352 (2004)

    Article  CAS  ADS  Google Scholar 

  29. Zatsiorsky, V. & King, D. An algorithm for determining gravity line location from posturographic recordings. J. Biomech. 31, 161–164 (1998)

    Article  CAS  Google Scholar 

  30. Phenice, T. W. A newly developed visual method of sexing in the Os pubis . Am. J. Phys. Anthropol. 30, 297–301 (1969)

    Article  CAS  Google Scholar 

  31. Ubelaker, D. H. & Volk, C. G. A test of the Phenice method for the estimation of sex. J. Forensic Sci. 47, 19–24 (2002)

    PubMed  Google Scholar 

  32. Washburn, S. L. & Buettner-Janusch, J. The definition of thoracic and lumbar vertebrae. Am. J. Phys. Anthropol. 10, 251–252 (1952)

    Google Scholar 

  33. Shapiro, L. in Postcranial Adaptation in Nonhuman Primates. (ed. Gebo, D.L.) 121-149 (Northern Illinois University Press, DeKalb, IL, 1993)

    Google Scholar 

  34. Schultz, A. H. The skeleton of the trunk and limbs of higher primates. Hum. Biol. 2, 303–438 (1930)

    Google Scholar 

  35. Rockwell, H., Gaynor Evans, F. & Pheasant, H. The comparative morphology of the vertebrate spinal column: its form as related to function. J. Morphol. 63, 87–117 (1938)

    Article  Google Scholar 

  36. Digiovanni, B., Scoles, P. & Latimer, B. Anterior extension of the thoracic vertebral bodies in Scheuermann’s kyphosis: an anatomic study. Spine 14, 712–716 (1989)

    Article  CAS  Google Scholar 

  37. Corruccini, R. S. Shape in morphometrics: comparative analyses. Am. J. Phys. Anthropol. 73, 289–303 (1987)

    Article  Google Scholar 

  38. Jungers, W. L., Falsetti, A. B. & Wall, C. E. Shape, relative size, and size-adjustments in morphometrics. Yb. Phys. Anthropol. 38, 137–161 (1995)

    Article  Google Scholar 

  39. Mosimann, J. Size allometry: Size and shape variables with characterizations of the log normal and gamma distributions. J. Am. Stat. Assoc. 65, 930–945 (1970)

    Article  Google Scholar 

  40. Darroch, J. & Mosimman, J. Canonical and principal components of shape. Biometrika 72, 241–252 (1985)

    Article  MathSciNet  Google Scholar 

  41. Sokal, R. R. & Rohlf, F. J. Biometry: The Principles and Practice of Statistics in Biological Research. 3rd Edition. (W.H. Freeman and Company, New York, 1995)

    MATH  Google Scholar 

  42. Jaccard, J. & Wan, C. K. LISREL Approaches to Interaction Effects in Multiple Regression (Sage, Thousand Oaks, CA, 1996)

    Book  Google Scholar 

Download references

Acknowledgements

We thank W. Sanders for fossil measurements and discussion; S. Ford, J. Jensen, J. Kappelman, D. Overdorff, D. Pilbeam, D. Raichlen, P. Rightmire and C. Ruff for comments and assistance with research; L. Gordon, D. Hunt, L. Jellema, B. Latimer and R. Thorington for access to specimens; and the Developmental Motor Control Laboratory at the University of Texas, Austin, for laboratory use. Figure 1 was drawn by L. Meszoly. This work was supported by grants from the National Science Foundation (to L.J.S. and K.K.W.), the L. S. B. Leakey Foundation (to K.K.W.), the National Science Foundation (to D.E.L.) and the American School of Prehistoric Research (Harvard).

Author Contributions K.K.W. designed the study, conducted the experiments, and analysed and interpreted the data. L.J.S. assisted in the study design and the interpretation of results. D.E.L. assisted in the fossil study design and in the analysis and interpretation of the fossil and biomechanical data. K.K.W., L.J.S. and D.E.L. wrote the manuscript.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Katherine K. Whitcome.

Supplementary information

Supplementary Information

The file contains Supplementary Tables 1-3, Supplementary Notes and additional references. (PDF 283 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Whitcome, K., Shapiro, L. & Lieberman, D. Fetal load and the evolution of lumbar lordosis in bipedal hominins. Nature 450, 1075–1078 (2007). https://doi.org/10.1038/nature06342

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature06342

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing