Thursday, October 1, 2020

Grandpa has the Back of a Chimpanzee!

You scoff at the ridiculous title, but it's true!

Herniation of an intervertebral disc is defined by protrusion, extrusion, or sequestration of that disc from its normal position. This pathology has the potential to go undiagnosed due to a lack of symptoms or produce debilitating problems for someone who suffers from a serious case. It is commonly associated with a radiating pain from the lower back to the outer thigh – sciatica (DynaMed).

A study carried out by Plomp et al, in 2015 explored the relationship between vertebral shape and the propensity to suffer from a disc herniation - more commonly known as a slipped disc. Humans are unusually apt to suffer from back issues at far higher rates than other non-human primates. You don't commonly hear about a chimp at your local zoo throwing out their back. The authors of this study hypothesized that in addition to disc shape, our unusual bipedal mode of locomotion could contribute to this pathology. They carried out their study with particular focus on human subjects whose vertebral morphology most resembled their ancestors – the chimpanzee and orangutan. The assumption was made that these individuals would be less equipped to walk upright.

          The study focused on the last thoracic and first lumbar vertebrae in the species comparison. They used specific landmarks on these vertebrae to measure the dimensions of the vertebrae of the three species. The authors found no significant difference between the measurements of chimpanzees and those of humans with a herniated disc – the vertebrae were identical. This data shows that those with vertebral morphology similar to that of early primates are less equipped for bipedal motion and more likely to slip a disc. Chimpanzee vertebrae, as well as humans with a slipped disc have a number of morphological differences from that of a healthy human – suggesting the possibility of diagnosis before a disc is slipped.

          Ancestral shape could inform health professionals about which of their patients are at risk for back issues before they arise and assist in prevention and treatment. Further research could be done to determine how best this data can be used. It’s incredible to think that our anatomy can resemble our ancestor’s so exactly – grandpa really did have the back of a chimp.

DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T116077Lumbar Disk Herniation; [updated 2018 Nov 30, cited 2020 Oct 1]. Available from https://www.dynamed.com/topics/dmp~AN~T116077. Registration and login required 

Plomp, K. A., Viðarsdóttir, U. S., Weston, D. A., Dobney, K., & Collard, M. (2015). The ancestral shape hypothesis: An evolutionary explanation for the occurrence of intervertebral disc herniation in humans. BMC Evolutionary Biology, 15(1), 68. https://doi.org/10.1186/s12862-015-0336-y


4 comments:

  1. I really enjoyed reading this post. Thinking about other species experiencing back pain is something that I have never thought about before. When comparing a species like humans that use bipedal motion to a species that use 4 limbs to move around I immediately think about gravity. Humans have much greater gravitational force on our backs and lower bodies. As an engineer, I would love to see a force analysis of bipedal vs quadpedal motion. In my opinion, understanding the force impact on different parts of the body could be a useful prevention tool for an injury like a slipped disc. Overall, I was intrigued by this study and would love to learn more about this topic.

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    1. A force analysis would be really interesting

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  2. This is a very interesting reading and I think it is very informative how you stated the significant similarities between these primates and humans. I wonder if this means that if people have a herniated disc they should focus more recovery on walking upright again or if it is better to be more quadrupedal recovery? I think it is really important to look at morphological differences and similarities so that we can make better predictions and strategies for solving these issues. I do wonder also if we should be comparing other animals that are similar to us to uncover more information about how certain body structures will affect different vertebrate structures. This was a very informative article and hopefully we find better ways to treat these issues by looking to our past.

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  3. This is a very interesting and informative read. To think that we can tell predict a spinal issue before it happens through measurements of someone’s vertebrae is quite fascinating. Now knowing this, I wonder if the techniques used in this study could be applied in routine physicals. Understanding what type of risk of injury individuals have could be very useful for the people to know. Also, I could very easily see these techniques being used in athletics to see if someone is more susceptible to a certain injury so they could better prepare the athlete.

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