Why Are Some People Double-Jointed?

  • Added:  3 months ago
  • You might have a friend who is “double-jointed" and can bend their fingers in freaky ways. Why are they are so flexible?

    Hosted by: Stefan Chin
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    Image Source:
  • EducationEducation
  • Runtime: 2:12
  • SciShow  science  Hank  Green  education  learn  Why Are Some People Double-Jointed?  flexible  double-jointed  party trick  joints  hypermobility  flexibility  ball-and-socket joint  hips  shoulders  fingers  elbows  bone  cartilage  elastic cartilage  hyaline cartilage  fibrous cartilage  tissue  ballerina  ligaments  Ehlers-Danlos Syndrome  dislocatioin  arthritis  

Comments: 894

  • Caleb Grassi
    Caleb Grassi 3 months ago +455

    Oh cool! It's stefan chin.

    • Peter Rabitt
      Peter Rabitt 3 months ago

      Stefan! Stefan! He's our man! If he can't do it....

      ...just call Michael Aranda.

    • pnkflyd66
      pnkflyd66 3 months ago


      First day on the internet?

    • Phirdeline
      Phirdeline 3 months ago

      I guess nothing will stop the culture of making comments all about the speaker at this point
      I don't really care wether those are good ones or stupid and ignorant ones but I just wish to see good old science discussions that would be here somewhere around couple years ago.

    • Lara Schilling
      Lara Schilling 3 months ago

      Hi Stefan! Good to see your face on the other side of the camera!

  • WierdHairGrows !
    WierdHairGrows ! Month ago

    I'm double jointed

    • WierdHairGrows !
      WierdHairGrows ! Month ago

      I can connect my hands together and twist my arms so they go over my head to the other side of my body I could also do the thing most people can do when they pop their thumb out and I'm not sure if dis last one is a double jointed thing, I only showed it to one person and they said it's pretty cool but I could use this tendon right on top of my big toe to lift and bend it up in dis weird way where u can see my tendon popping out (sorry if u don't understand my explaining)

  • colleen durkan
    colleen durkan Month ago

    my nee can go backwords

  • trash you watch when your bored

    I'm double jointed

  • Alice Red
    Alice Red 2 months ago +1

    My knees are double jointed. I hate when people tell me "If you want to do ____ right, lock your knees" and I'm sitting here like "Cannot physically do that, thanks."

  • Harper
    Harper 2 months ago

    Wait I thought elbows were hinge joints

  • Copy My Drug And Alcohol Fueled Rants

    I have a question for Scishow, how did you guys manage to bastardized pop-science into something that is as about as scientific as reality television?

  • DarthPotter1997
    DarthPotter1997 2 months ago

    I've dislocated my knee cap 3 times because of flexible ligaments.

  • TheFlying Eevee
    TheFlying Eevee 2 months ago +1


  • Andrea Fung
    Andrea Fung 2 months ago

    I have hypermobility can I have dislocated my knee many times and it's painful and hard to look at cause the knee cap sticks out and it looks very painful

  • MsEeveeMaster
    MsEeveeMaster 2 months ago

    so is that why I sprain my knees so easily?

  • hacker hacker
    hacker hacker 2 months ago

    first act like your giving someone a high five or tracing your hand then bend you then down you can't do more than a flat angle but I can make it point straight down

  • Roberto Vargas
    Roberto Vargas 2 months ago

    who the heck is this new guy?

  • Ananyo Ganguly
    Ananyo Ganguly 2 months ago +1

    I like the way he tries to make us feel good who can't touch our fingertips to the back of the hand and therefore not cool.
    Appreciate it.

  • Lila Rose
    Lila Rose 2 months ago

    Part of the extreme stretchy cartilage people and the forever knuckle popping out group

  • Terible Teri
    Terible Teri 3 months ago

    my chiropractor just calls me Gumby...

  • Fabian-Eduardo Chacon
    Fabian-Eduardo Chacon 3 months ago

    I came here bEcause 1. Im double Jointed 2. How in the world did that kid in the thumbnail do that! I CANT DO THAT

  • kitty cat
    kitty cat 3 months ago

    oh god, an emoji movie ad

  • Faelyn Dexter
    Faelyn Dexter 3 months ago

    The Elbow is not a Ball and Socket joint. It's a Hinge joint.

  • JTSharkAttack
    JTSharkAttack 3 months ago

    My thumbs and pinkies are double jointed.

    Give me attention

  • Etienne Venegas
    Etienne Venegas 3 months ago

    I was watching this and giggling at the same time. Since I was little I've been able to lick me elbows, hold my hands together and rotate behind me and forward again looks creepy af but funny, and put my hands flat on the surface of a table (me standing) and rotate my hands inward and outward to do a full 360° and can hyperflex my fingers. Looks like my joints might hurt a lot in my future lol

  • TheJiamy
    TheJiamy 3 months ago

    I have hyper mobility in my neck and elbows according to the physical therapist I visited and it caused me a LOT of neck pain let me tell u

  • Hack Up
    Hack Up 3 months ago

    how come some people can rotate thier heads almost 360?

  • RickySTT
    RickySTT 3 months ago

    I though the elbow was a hinge joint.

  • Mauricio Aguilera
    Mauricio Aguilera 3 months ago

    I can turn my right foot around

  • Will Stewart
    Will Stewart 3 months ago

    I can spin my foot both ways backwards

  • James Borland
    James Borland 3 months ago

    Ha, requires a doctor to fix

  • Scott Walton
    Scott Walton 3 months ago

    a joint is a cig paper with weed in place of tobacco...u dumbass

  • Lilmaderr23
    Lilmaderr23 3 months ago

    This doesn't explain why people's fingers are double jointed. #FalseAdvertising

  • Mike Czenkus
    Mike Czenkus 3 months ago

    Stefan is the man!

  • NP_99 T
    NP_99 T 3 months ago

    When I was younger I could freak people out by bending my right index finger all the way back but now that I'm older I can't even bend it 3/4 of the way without it hurting. Why is this?

  • Hun Ter
    Hun Ter 3 months ago

    I, Hunter Rudkin, can put my left leg over my head whilst jumping on my right one. For whatever reason, it grosses people out. It just feels so natural to me.

  • r2pen2
    r2pen2 3 months ago

    I have Ehlers-Danlos Syndrome, but it's not as bad as he describes it for me. I just have to be careful not to pull a muscle by accident and my hand gets tired. This is the first time I've ever heard anyone else mention it though!

  • Larry Wang
    Larry Wang 3 months ago

    I thought double jointed was when you rolled two joints for you and your friend, but then end up smoking both of them yourself at the same time...

  • thefudgestix
    thefudgestix 3 months ago

    What's the opposite of double-jointed? Because that's me.

  • Mason Westphal
    Mason Westphal 3 months ago

    @SciShow do sidewalks increase earthworms likelihood of survival in a rain storm?

  • sachikoaichan
    sachikoaichan 3 months ago

    I have hypermobility in my hands and back, it's only good for freaking people out, and winning bets. "Bet you can't touch the floor with your palms flat while keeping your knees straight."

  • mindsendStoryweaver
    mindsendStoryweaver 3 months ago

    ALSO as someone with hyper-mobility, it increases the chances of developing things like carpal tunnel according to my orthopedist.

  • Ieuan Hunt
    Ieuan Hunt 3 months ago

    Errr our Elbows aren't ball and socket joints. They're hinge joints, Just want to point that out as mistakes like this undermine your credibility.

  • HX Malcolm
    HX Malcolm 3 months ago

    What is the difference between viruses and bacteria

  • William Howton
    William Howton 3 months ago

    As someone who has hypermobility, let me say this. It is really fun to mess with people... Until your knees pop out if you sit down wrong.

  • CSI Rusty48
    CSI Rusty48 3 months ago


  • Michael Phelps
    Michael Phelps 3 months ago

    So basically people double jointed are action figures.

  • tgtaa
    tgtaa 3 months ago


    I am afraid that is rather inaccurate. The hip joint and the shoulder joint (glenohumeral joint) are truly ball-and-socket joints, whereas the elbow is a hinge joint.

  • Aku vs. Jack
    Aku vs. Jack 3 months ago

    so i can dislocate my shoulder and pop it back into place without even touching it. i learned how to make my shoulder and arm muscles do it. it's a party trick that freaks people out, especially if they feel it since you can feel the tendons and things. it's still neater for me to do then my ability to move each eye separately in whatever direction.

  • Gwenyvere White
    Gwenyvere White 3 months ago

    How do organs collapse

  • KendrickMan
    KendrickMan 3 months ago

    If anyone wants to see a hypermobile elbow HMU

  • Jack Feldcher
    Jack Feldcher 3 months ago +1

    These videos need more views just like their subscribers

  • linmonPIE
    linmonPIE 3 months ago

    When stretching my arms people sometimes freak out because my elbows bend backwards at an extreme angle. Can anyone else relate?

  • Gabriel Martins
    Gabriel Martins 3 months ago

    Who the fuck
    and where's Olivia
    I miss the bounce.

  • Azure Kite
    Azure Kite 3 months ago

    My knee's joint is shallow, and that doesn't make me hypermobile, it just makes my knee really easy to dislocate ):

    Panda YT CANAL VECHI! 3 months ago

    Not moving your arms while talking makes it very awkward for me to watch this video:)).
    The body language is very important in these types of videos. In the following videos, move your arms more, take it as a advice. Thanks!

  • Jo Ne
    Jo Ne 3 months ago

    Wtf thumbnail lmao

  • Chloe Kirk
    Chloe Kirk 3 months ago

    I can lick my elbow, but not as a result of being double jointed. I just have short upper arms. And I like the new host! Yay SciShow!

  • The Humming Boy
    The Humming Boy 3 months ago +1

    +scishow Very informative video, but the elbow is essentially a combination of a hinge joint (between the ulna and the humerus) and a pivot joint (between the radius and the ulna). The hinge joint allows us to bend our elbow while the pivot joint permits the twisting motion that let our forearm and palms face upwards and downwards (the technical term would be supination and pronation). So it would be technically incorrect to call the elbow a ball-and-socket joint as it does not move in all 3 planes in the physical dimension. Full time PT student here.

  • Spoons
    Spoons 3 months ago

    I can bend my elbow backwards

  • Jelani Alleyne
    Jelani Alleyne 3 months ago

    since when elbows have ball and socket joints.???? hinge....

  • mohnblume11
    mohnblume11 3 months ago

    Good timing, May is EDS awareness month. Be aware, people!

  • Zodd
    Zodd 3 months ago

    Anyone but the girl. please just dont have her in videos anymore. thank you.

  • Leopard-King
    Leopard-King 3 months ago

    I thought being double jointed was holding reefer in both hands. Ohhhh, no sorry that is being ambidextrous. Obviously that poor little boy was mangled in a car crash, are they giving him weed for the pain?

  • Shaun Webb
    Shaun Webb 3 months ago

    elbow totally not a ball and socket joint haha

  • Clementx84
    Clementx84 3 months ago

    Elbows are classified as ginglymus (hinge) joints, not ball and socket.

  • Logan Hall
    Logan Hall 3 months ago

    official tone isolate during yield historic investor widespread.

  • Dharmanshu Satyavna
    Dharmanshu Satyavna 3 months ago

    wow I have quark's

  • Megan Tate
    Megan Tate 3 months ago

    Hypermobile zebra here! Cool video and thanks for the awareness ❤️

  • ThinkYou
    ThinkYou 3 months ago

    Golden Ratio (Phi) = 1.618 is the ratio of any two consecutive numbers in The Fibonacci Series. This ratio exists everywhere in the cosmos from, waves and sea shells to the shape of the galaxies. From sunflowers to the style of Aston Martin. Surprisingly, this is also the ratio of the human finger bones!

  • CelesteofOz
    CelesteofOz 3 months ago

    Well my kid has rubber joints, but her injuries heal crazy fast - almost overnight. Maybe she's actually an alien.

  • Jeff Tan Han Wei
    Jeff Tan Han Wei 3 months ago

    I had a cousin who is double jointed and he can bend his fingers. I was like O_O but he can only do it on his left hand lol

  • SonoftheWay35
    SonoftheWay35 3 months ago

    This guy might be the best host, keep him.

  • Savage Donut
    Savage Donut 3 months ago

    Where is Hank green ): no offense

  • Anju Maaka
    Anju Maaka 3 months ago

    The elbow isn't a "ball" joint is it? It only bends in one direction (unlike shoulders which can roll in any direction). The elbow bends just like fingers doesn't it? One way

  • Robin Hallie
    Robin Hallie 3 months ago

    a hindge joint is in the elbow

  • Stingblade 11
    Stingblade 11 3 months ago

    I can pop my in & out shoulder at the drop of a hat it hurts a bit

  • Zebra Zahara
    Zebra Zahara 3 months ago

    Elbows don't have a socket, the elbow is a hinge joint

  • Zamp Magic
    Zamp Magic 3 months ago

    Ehlers Danlos Awareness Month! Yay SciShow! I love you guys and have wanted you to mention my disorder for a long time. Happy EDS awareness month to you all!

  • Scheefinator
    Scheefinator 3 months ago

    Dislocated my kneecap twice, few years apart from one another and the same knee. Words do not describe that pain. It still haunts me to this day.

  • Jey Smith
    Jey Smith 3 months ago

    Ball and socket joint...elbows? What?

  • Hannah
    Hannah 3 months ago

    My ankles are hypermobile and it's the WORST. I found out through my physical therapist that that's why my ankles are just the worst things on/in my body.

  • Toasted Awesomeness
    Toasted Awesomeness 3 months ago

    0:43 Elbow? Are you sure about that

  • BlackStarVega
    BlackStarVega 3 months ago

    What a Short yet Informative Video... Thank you :-)

  • The Adult Project
    The Adult Project 3 months ago

    so much love to my fellow zebras out there<3

  • Adam Sheppard
    Adam Sheppard 3 months ago

    I'm double jointed, and my joints have always painlessly dislocated, which is nice, I guess

  • AngryAlien21
    AngryAlien21 3 months ago

    Thank you for the EDS exposure. It is actually Ehlers-Danlos awareness month. Hypermobility is only one form of EDS, and a lot of us have much more severe symptoms

  • Justin Bonney
    Justin Bonney 3 months ago

    who the fucks this guy?

  • jack nimb
    jack nimb 3 months ago

    I can touch my wrist

  • Evan Smith
    Evan Smith 3 months ago

    What about being able to pop joints out of place with no pain, is that similar to hypermobility or completely different?

  • RietjeRox
    RietjeRox 3 months ago

    I used to get back and hip pain all the time (esp after stopping weekly sport) and still occasionally my wrist and knee joints are oddly sensetive for no good reason, but I've found excercise (on strength-base, but still stretching too) really helps. It especially helps for my back, hips and shoulders. I don't have EDS though, so i'm in luck. If you find you want to support your flexible joints more, maybe also considder regular excercise with a reasonable (not too heavy) weight; i feel better doing more excercise with small weight than less with more weight bc then i overstretch my joints more easily.

  • Chump
    Chump 3 months ago

    "keep these answers coming" haha 1:49

  • Lewis Rainwater
    Lewis Rainwater 3 months ago

    It has finally been asked.

  • Derek Garret
    Derek Garret 3 months ago

    who the fuck is this nerd where hank at!!!##!

  • Jeremy Ellwood
    Jeremy Ellwood 3 months ago

    Wait... our elbows are ball and socket? My biology class from high school tends to disagree.

  • tdshat
    tdshat 3 months ago

    i have no cartilage in my ears what is that called

  • Abigail Wildlife
    Abigail Wildlife 3 months ago

    My friend can bend their elbow like the other way

  • Katie Wood
    Katie Wood 3 months ago

    This is the most reserved I've ever seen Stefan. Great job but I wouldn't object to your crazy voices and expressions to spice it up a little :)

  • Sean
    Sean 3 months ago

    The only joints in the L-bow are the Hinge or Synovial Joint and the Pivot Joint. :)

  • Tobias Eklund
    Tobias Eklund 3 months ago

    yes, but why are some joints double-peopled?

  • Katherine Martell
    Katherine Martell 3 months ago

    Hypermobility = when you unintentionally pop your hip while figure skating and have to pop it back in right then and there because you're only standing on one leg and the other in in the air above your head while you're leaning over backwards moving at really fast speeds, and it's the only way you can get your leg down. Oh and you have 12 inch blades attached to your feet and no helmet

  • Murcury
    Murcury 3 months ago

    question: how can I dislocate (and relocate) my shoulder on command without touching it at all?

  • Jake Stockton
    Jake Stockton 3 months ago

    What's so hard about having Hank as the host? Is he golfing with Trump or something?

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