Читать книгу The House We Live In; or, The Making of the Body онлайн

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Percy: The shoulder joint.

Mother: Is this joint like the one in your elbow?

Helen: No, for I can swing my arm backward or forward or any way I like.

Mother: That is because it has a different joint than your elbow. It is called a “ball-and-socket” joint; that is, one end of the bone is shaped like a ball, and this fits into a hole shaped like a cup in another bone, like the one you see in the picture. This shows the hip joint, which is also a ball-and-socket joint, the same as we found in the shoulder. Now what is the joint called at the lower end of the forearm?

Amy: It is called the wrist.

Mother: The wrist is a joint that moves very easily in many different ways. Now how many joints, or bending-places, have we found in the arm?

Percy: The arm has three joints.

Mother: Elmer, you may take this ball. With what do you hold it?

Elmer: With my hand.

Mother: Tell me some ways in which we use our hands.

Helen: We hold, push, pull, lift, catch, and feel with our hands.

Mother: The inside is called the palm of the hand. What do you find at the ends of your hands?