BONES AND JOINTS

BACKGROUND

We are going to build a model of an arm to see how joints and muscles work. Like all models, it will be like the real thing in some ways and very different in others. Spend some time investigating your own arm. How is it made? In what ways can it move?

MATERIALS NEEDED

3 skill sticks
1 Styrofoam ball
1 bottle cap
masking tape

MAKE THE MODEL

1. Mark the three skill sticks as shown in Figure 1. Note that some of the markings are made on the underside of the stick. Break the sick where shown. Note that E stands for "elbow" and H for "hand".

2. Assemble the shoulder joint as shown in Figure 2.

3. Now assemble the elbow as shown in Figure 3. Be sure to leave space between the humorous and the ulna about the thickness of a skill stick.

QUESTIONS

1. What bone is missing from this model?

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2. What type of motion does this missing bone allow?

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3. Describe each joint:

JOINT	TYPE	TYPE OF MOTION
Shoulder
Elbow

4. Knowing that we still have to attach muscles, what do you think "T", "D" and "B" might stand for?

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