# how wide can a human jaw open?

**URL:** <https://boards.straightdope.com/t/how-wide-can-a-human-jaw-open/798058>\
**Category:** Factual Questions\
**Created:** [October 5, 2017, 8:49pm UTC](https://boards.straightdope.com/t/how-wide-can-a-human-jaw-open/798058 "2017-10-05T20:49:47Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Contemplation](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Contemplation](https://boards.straightdope.com/u/Contemplation)\
**Post date:** [October 5, 2017, 8:49pm UTC](https://boards.straightdope.com/t/how-wide-can-a-human-jaw-open/798058/1 "2017-10-05T20:49:47Z")

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How wide can you open you jaw In terms of angle?  
Is it possible for someone to completely open their mouth 90 degrees or even 180 degrees?

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**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\
**Post date:** [October 5, 2017, 8:51pm UTC](https://boards.straightdope.com/t/how-wide-can-a-human-jaw-open/798058/2 "2017-10-05T20:51:34Z")

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Not without major damage…

Are you asking about voluntary opening or forced opening? Because if the latter sure, you could come up with a scenario where some poor soul’s lower jaw is ripped off so sure, destroy the joint and open wide.

Voluntary? Not so much. Definitely not 180 degrees.

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**Author:** ![Weisshund](https://avatars.discourse-cdn.com/v4/letter/w/ba8739/32.png) [@Weisshund](https://boards.straightdope.com/u/Weisshund)\
**Post date:** [October 5, 2017, 9:04pm UTC](https://boards.straightdope.com/t/how-wide-can-a-human-jaw-open/798058/3 "2017-10-05T21:04:33Z")

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In the dental surgeons chair?  
Quite wide, and you do not want to be awake for it.  
You wont like it much when you wake up either

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**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\
**Post date:** [October 5, 2017, 9:15pm UTC](https://boards.straightdope.com/t/how-wide-can-a-human-jaw-open/798058/4 "2017-10-05T21:15:01Z")

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If you believe [this](https://www.vivahealth.org.uk/wheat-eaters-or-meat-eaters/gape-mammals) chart, it is somewhere between 65 and 85 degrees. But of course it depends on the individual–sitting here opening my mouth and feeling around my mouth and jaws like an idiot, I’m estimating my maximum to be less than 45 degrees.

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**Author:** ![Contemplation](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Contemplation](https://boards.straightdope.com/u/Contemplation)\
**Post date:** [October 5, 2017, 9:20pm UTC](https://boards.straightdope.com/t/how-wide-can-a-human-jaw-open/798058/5 "2017-10-05T21:20:11Z")

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voluntary of course with just your own jaw/mouth.