Common myth: skin wrinkles in water because of osmosis/swelling.

Reality: it is an active, involuntary vasomotor response. The nervous system constricts blood vessels under the skin to form ridges—acting like tire treads to channel away water and improve grip on wet objects. Patients with severed median nerves don't wrinkle at all.

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[–] 23 points 5 hours ago* (last edited 5 hours ago) (8 children)

AI slop, source links also incorrect. This is a waste of everyone's time.

Because i got curious: Water immersion skin wrinkling is an indicator of limb sympathetic function. Routine clinical usage of this enigmatic phenomenon is hampered by poor endpoint quantification, which involves counting skin folds. The recent discovery of the importance of vasoconstriction in immersion wrinkling suggests digital blood flow or volume changes as better endpoints. Water probably initiates the wrinkling process by altering epidermal electrolyte homeostasis as it diffuses into the porous skin of the hands and soles via its many sweat ducts. Altered epidermal electrolyte homeostasis would lead to a change in membrane stability of the surrounding dense network of nerve fibers and trigger increased vasomotor firing with subsequent vasoconstriction. Vasoconstriction, through loss of volume, leads to negative digit pulp pressure resulting in a downward pull on the overlying skin, which wrinkles as it is distorted. The degree of wrinkling would directly depend on the change in digit tip volume and implies any process inducing loss of digit volume will precipitate wrinkling. This review discusses the physiology of water immersion wrinkling and explores its potential as an indicator of limb sympathetic dysfunction.

https://pubmed.ncbi.nlm.nih.gov/15095056/

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  • [–] 7 points 4 hours ago (4 children)

    How does what you linked conflict with what OP said?

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  • [–] 10 points 3 hours ago (3 children)
    1. It's a loss of volume, not vasomotors pulling the skin 'down', though that can be chocked up to phrasing.

    2. It is still caused by water absorption, though not directly and not only.

    3. The medical paper makes no mention of "improving grip". That conclusion seems to be spurious and almost certainly wrong. The tire tread bit is particularly hilariously dumb. Your fingertips don't need to shed water like a tire ffs.

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  • The medical paper makes no mention of "improving grip". That conclusion seems to be spurious and almost certainly wrong. The tire tread bit is particularly hilariously dumb. Your fingertips don't need to shed water like a tire ffs.

    That theory has been around for ages, much longer than AI. I recall reading it in Readers Digest as a kid. It's also listed in Wikipedia as a probable reason with some studies backing it up.

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  • [–] 1 point 2 hours ago

    This is also one of the things slop loves to add, spurious 'reasons' for things happening like my mother in law does.

    Did she see the dog pee on some dead grass? That means if the dog pees literally anywhere it is going to kill the grass!

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  • [–] 2 points 3 hours ago (1 child)

    Thank you. I appreciate you getting a link to an actual scientific source. There are way too many of these slop sites around these days.

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  • [–] [S] 5 points 4 hours ago

    The PubMed paper you linked actually explains the exact same mechanism stated in the post—vasoconstriction and vasomotor firing driven by the sympathetic nervous system, rather than passive osmotic swelling.

    Appreciate you linking the Wilder-Smith review though, it’s a great addition for anyone wanting the deeper clinical neurophysiology.

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  • [–] 27 points 6 hours ago (9 children)

    So theoretically there might be a possibility to acquire an ability to wrinkle myself at will? Cool!

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  • [–] 32 points 5 hours ago (3 children)

    ability to wrinkle myself at will

    That's gotta be the shittiest superpower...

    "I'm Superman! I fly at supersonic speed!"
    "I'm Aquaman! I breathe underwater!"
    "I'm Wrinkleman! I camouflage as a giant scrotum!"

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  • [–] 12 points 6 hours ago

    Future genetically enhanced super-soldiers: bulging bicepses lined with testosterone ampules, merciless eyes with sclera flooded red, and permanently wrinkled butt cheeks, for better grip of course.

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  • [–] [S] 6 points 5 hours ago

    Haha, unfortunately it's strictly controlled by the autonomic nervous system (same system as goosebumps and pupil dilation), so voluntary control is locked out. Would make a wild party trick though!

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  • [–] 6 points 6 hours ago (3 children)

    I always thought finger skin that's been wet long enough got confused and took itself for clammy scrotum skin.

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  • [–] [S] 6 points 5 hours ago (2 children)

    Lmao, new evolutionary hypothesis unlocked! Thankfully the actual biology is slightly more dignified than that haha.

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  • [–] 1 point 5 hours ago (4 children)

    Tell that to my very smooth pinky finger which lives in a warm coffee mug.

    Reality: it's actually in someone's butthole. Very detachable. I rent it out on the weekends.

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  • [–] 4 points 5 hours ago (3 children)
  • [–] 2 points 5 hours ago (2 children)

    *Detachable Penis" is already a song

    She's got a detachable penis, detachable penis... Zappa? No, someone else. Catchy tune.

    Btw, catch!

    Throws sloppy dong

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