Confocal scanning optical microscopy of a 3-million-year-old australopithecus afarensis femur

T. G. Bromage, H. M. Goldman, S. C. McFarlin, A. Perez Ochoa, A. Boyde

Research output: Contribution to journalArticlepeer-review


Summary: Portable confocal scanning optical microscopy (PCSOM) has been specifically developed for the noncontact and nondestructive imaging of early human fossil hard tissues, which here we describe and apply to a 3-million-year-old femur from the celebrated Ethiopian skeleton, "Lucy," referred to Australopithecus afarensis. We examine two bone tissue parameters that demonstrate the potential of this technology. First, subsurface reflection images from intact bone reveal bone cell spaces, the osteocyte lacunae, whose density is demonstrated to scale negatively with body size, reflecting aspects of metabolism and organismal life history. Second, images of a naturally fractured cross section near to Lucy's femoral mid-shaft, which match in sign those of transmitted circularly polarized light, reveal relative collagen fiber orientation patterns that are an important indicator of femoral biomechanical efficacy. Preliminary results indicate that Lucy was characterized by metabolic constraints typical for a primate her body size and that in her femur she was adapted to habitual bipedalism. Limitations imposed by the transport and invasive histology of unique or rare fossils motivated development of the PCSOM so that specimens may be examined wherever and whenever nondestructive imaging is required.

Original languageEnglish (US)
Pages (from-to)1-10
Number of pages10
Issue number1
StatePublished - Jan 2009


  • Australopithecus afarensis
  • Collagen fiber orientation
  • Confocal microscopy
  • Early hominid
  • Osteocyte lacunae

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Instrumentation


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