A fl amingo’s ankles are high up on its legs. You might think they are knees.


Bodies in Motion Bones do more than support and protect your body. Bones work with muscles to move your body. Here’s an example. Bend your arm.


Your upper arm muscles go to work. T e front muscle tightens. It pulls the bones in your lower arm forward. Your elbow bends. To lower your arm, the muscle in the back of your arm tightens. Your arm pulls back. T e place where bones meet is


called a joint. Some joints work like a door hinge. T ey bend back and forth.


6 NATIONAL GEOGRAPHIC EXPLORER


Bending and Turning What looks like a flamingo’s knee bends backward. Don’t be fooled. T at’s its ankle. T e bird’s knee is hidden under feathers. Both joints work like hinges. Other joints help bones turn. Move


your head leſt and right. Now move it up and down. T at’s your neck joint at work. An owl’s neck joint lets it turn its head almost all the way around.


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