A team of bioarchaeologists think they may have discovered the first quantified evidence showing a relationship between upright locomotion and spinal health.

They have found that those with lower back problems are more likely to have a spine shape similar to that of our closest ape ancestors, identifying for the first time that the way in which humans evolved plays a critical role in this painful complaint.

Kimberly Plomp, a postdoctoral researcher in the Human Evolutionary Studies Program at Simon Fraser University, and researchers from the University of Aberdeen, the University of British Columbia, and the University of Iceland used two-dimensional shape analyses of the vertebrae of chimpanzees, orangutans and archaeological humans to investigate the relationship between vertebral shape, upright locomotion and human spinal health.

Plomp noted in a press release: “We found that some characteristics of human vertebrae differ in shape between those individuals that have a lesion called a Schmorl’s node – a small hernia that can occur in the cartilaginous disc between the vertebrae. The humans that have Schmorl’s nodes tend to have a shape that is statistically indistinguishable from chimpanzee vertebrae.”

The researchers noted: “evolution is not perfect and some vertebral characteristics, such as the ones we identified as being similar to chimpanzees, may have remained within the human ‘blueprint’ and result in some people having vertebrae that are less able to withstand the pressures of bipedal walking.”

The team has called this the ‘ancestral shape hypothesis’ and plan to undertake further investigations using 3D shape studies of ancient and modern human and primate vertebrae, and include other spinal diseases, such as osteoarthritis.

Reference

1. Plomp KA, et al. BMC Evolution Bio. 2015; 15:68.