The Ancestral Shape Hypothesis: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4410577/ https://www.liverpool.ac.uk/archaeology-classics-and-egyptology/blog/2020/ancestral-shape-hypothesis/ The most common direct causes of disc herniation: https://www.ncbi.nlm.nih.gov/books/NBK441822/#:~:text=The%20most%20common%20cause%20of,of%20disc%20herniation%20is%20trauma. ---- Subscribe to our newsletter! http://eepurl.com/Bgi9b And join the community at http://nerdfighteria.com/ Help transcribe videos - http://nerdfighteria.info/ Learn more about our project to help Partners in Health radically reduce maternal mortality in Sierra Leone: https://www.pih.org/hankandjohn If you're able to donate $2,000 or more to this effort, please join our matching fund: https://pih.org/hankandjohnmatch If you're in Canada, you can donate here: https://pihcanada.org/hankandjohn John's twitter - http://twitter.com/johngreen Hank's twitter - http://twitter.com/hankgreen Hank's tumblr - http://edwardspoonhands.tumblr.com/