Capillary diameter and geometry in cardiac and skeletal muscle studied by means of corrosion casts
Two pages on PainSci cite Potter 1983: 1. The Complete Guide to Patellofemoral Pain Syndrome 2. Ugly Bags of Mostly Water
PainSci notes on Potter 1983:
I went looking for this paper because I wanted to know how big capillaries are, and how that compares to thinks like spider silk and human hairs. Both hair and silk come in a wide variety of thicknesses, but this fact is routinely ignored. For instance, spider silk will be described as being a tenth the thickness of a human hair. Which spider? Whose hair? I haven’t documented my sources because it’s a trivial, gee-whiz point, but the process of clearing this up was interesting. Turns out that human hair diameter ranges from about 15 micrometres at its finest, all the way up to 200 micrometres at the thickest: a full order of magnitude difference! Capillaries, on the other hand, are more consistent at around 4-6 micrometres: something like a third to a fortieth the thickness of hair, depending on the hair. Definitely smaller! Now spider silk turns out to have a really wide range of sizes. The very thinnest is measured in nanometres, just 10 of them, which is really impressive (nanometres are used to measure things on the molecular scale). At the other end of the range, spiders sometimes pump out silk as thick as 150 micrometres, a relatively gargantuan tenth of a millimetre and about the same size as the heaviest hairs. So, capillaries can be up to 500 times larger than really fine spider silk, or about thirty times smaller than the thickest.
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- Gabapentinoids and Risk of Hip Fracture. Leung 2024 JAMA Netw Open.
- Classical Conditioning Fails to Elicit Allodynia in an Experimental Study with Healthy Humans. Madden 2017 Pain Med.
- Topical glyceryl trinitrate (GTN) and eccentric exercises in the treatment of mid-portion achilles tendinopathy (the NEAT trial): a randomised double-blind placebo-controlled trial. Kirwan 2024 Br J Sports Med.
- Placebo analgesia in physical and psychological interventions: Systematic review and meta-analysis of three-armed trials. Hohenschurz-Schmidt 2024 Eur J Pain.
- Recovery trajectories in common musculoskeletal complaints by diagnosis contra prognostic phenotypes. Aasdahl 2021 BMC Musculoskelet Disord.