Adam's apples are found on both women and men they just show up more prominently in men as a chunk of bony cartilage that's wrapped around the larynx.
Also known as the laryngeal prominence, the Adam's apple sits right on top of the thyroid gland, so the area is fittingly called the thyroid cartilage.
So what makes Adam's apples stick out more in men? Because grown men have larger voice boxes, theirs are a lot more prominent. This is also the reason why dudes speak in deeper tones.
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Girls and boys start out with similarly sized thyroid cartilage, but this changes when they hit puberty. The boys' Adam's apples become noticeably bigger and their voices change as their testosterone levels increase.
But does it do anything? Not really. Like the cartilage in your ears or nose, it's just kind of there. Some men with especially prominent bumps even have them surgically shaved, with no ill effects.
Unfortunately, the Adam's apple's main purpose may be embarrassing men at the office, during presidential debates, or while lying to their wives. Besides bobbing around when swallowing, the apple can "jump" uncontrollably when you're nervous . Gulp!
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