Your Body Is Full of Spare Parts

Touch your thumb to your pinky and bend your wrist. See a thin cord? About 1 in 5 people don't have it, and they grip just as hard. 🖐️ Your body is full of spare parts: leftovers from ancestors who climbed trees, breathed through gills and had tails. 12 of them, 9 you can test on yourself right now, and the most famous "useless" one saved for last. Your turn: how many of the 9 tests did you pass? Tell us your score 👇 And pick our next video: comment VOMIT (why can't rats throw up?) or GRANDMAS (why do only humans have grandmas?). CHAPTERS 0:00 Your body's spare parts 0:19 1. The wrist cord (palmaris longus) 1:56 2. Ear muscles 3:02 3. Your third eyelid 3:48 4. The ear bump (Darwin's tubercle) 4:55 5. Goosebumps 6:05 6. Wisdom teeth 7:15 7. The baby grip 8:19 8. Hiccups 9:41 9. Your tail 10:58 10. Ghost muscles 11:40 11. Your second nose 12:23 12. The appendix 14:08 Your score SOURCES (key papers) • Yammine 2013, Clin Anat 26:709 (palmaris longus prevalence) • Pękala et al. 2017, J Plast Reconstr Aesthet Surg 70:1715 • Sebastin et al. 2005, J Hand Surg Br 30:406 • Throckmorton et al. 2015, bioRxiv 015321 (preprint) • Senter & Moch 2015, PeerJ 3:e1439 • Wiedersheim 1895, The Structure of Man (Macmillan) • Darwin 1871, The Descent of Man; Darwin 1872, The Expression of the Emotions • Strauss et al. 2020, eLife 9:e54536 • Schroeer et al. 2025, Front Neurosci 18:1462507 • Loh & Cohen 2016, Dermatol Ther 6:143 • Millard & Pickard 1970, Arch Otolaryngol • Shwartz et al. 2020, Cell 182:578 • Carter & Worthington 2015, J Dent Res 94:886 • Pinto et al. 2024, J Clin Med 13:7533 • von Cramon-Taubadel 2011, PNAS 108:19546 • Lieberman et al. 2004, J Hum Evol 46:655 • Futagi et al. 2012, Int J Pediatr 2012:191562 • Robinson 1891, "Darwinism in the Nursery", Nineteenth Century • Straus et al. 2003, BioEssays 25:182 • Howes 2012, BioEssays 34:451 • Guinness World Records: longest attack of hiccups • Fallon & Simandl 1978, Am J Anat 152:111 • Xia et al. 2024, Nature 626:1042 • Diogo et al. 2019, Development 146:dev180349 • Olewnik et al. 2025, Biology 14:696 • Smith, Laitman & Bhatnagar 2014, Anat Rec 297:2196 • Bollinger et al. 2007, J Theor Biol 249:826 • Smith et al. 2013, C R Palevol 12(6); Smith et al. 2017, C R Palevol 16:39 • Im et al. 2011, Clin Gastroenterol Hepatol 9:1072; Naga et al. 2023, Dig Dis Sci 68:3714 "Vestigial" means a part lost its original job, not that it is useless. Some ideas here (hiccups, the appendix as a gut "safe house") are leading hypotheses, and we say so. Not medical or dental advice: ask your doctor or dentist. Illustrations made with AI image tools, then selected and edited by hand. Voice-over: CapCut text-to-speech. #science #evolution #humanbody