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Y
ou’ve got two! They’re amazing! They are your opposable thumbs.
The thumb is the key to how humans hold things. No other living
thing has a hand and thumb exactly like yours. But what is an
opposable thumb?
An opposable thumb allows you to touch the tip of your thumb to the
tip of each finger. Try it! Then try to touch the tip of your index finger
to the tip of your pinkie. Your fingers are designed to work together with
your thumb. This allows you to use your hands in many different ways.
Because we can hold things between the thumb and other fingers, we
are able to pick up even tiny objects. This is called a precision grip. How
important is your thumb? Try picking up a pen and writing without
using your thumb.
What makes the
thumb work the way
it does? A unique joint
connects the thumb to
the palm. This joint is
called a saddle joint.
The thumb is the only
place the saddle joint
is found. This joint
allows the thumb to
move side to side and
back and forth. The
human saddle joint is
very strong.
Your Amazing
Opposable Thumbs
Carpals
Metacarpals
Phalanges
Saddle
joint of
the thumb
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