How to Make a Model of the Pivot Joint

Pivot bones such as the radius and ulna allow for circular movement.
••• Thinkstock/Comstock/Getty Images

Pivot joints such as the forearm's radius and ulna bones move by allowing one's cylindrical shape to rotate within a type of cavity in the other. Holding your hand out and moving your hand from horizontal to vertical demonstrates this within the elbow. The hand pivots, while the elbow can remain stationary. Modeling these types of joints will allow the student to see how the joints and movement works without being obstructed by skin and tissue.

    Rub and squeeze a ball of modeling clay in your hands to warm it until it is soft and pliable. Mold it into two shapes similar to the radius and ulna after studying a picture of these two bones in the arm and noticing where the rounded areas are. It does not have to be exact, but one needs to be more cylindrical, while the other needs to feature a dip where the cylinder can rest and move. Place a needle through the top of each model bone at both ends.

    Place on a cookie sheet and bake at 200 degrees Fahrenheit until the clay is set. This may take 15 minutes to an hour depending on the thickness and type of clay used. Remove from the oven using the pot holder. Allow to cool for a few minutes. Wiggle the needles around while the clay is still warm. Remove the needles, leaving holes.

    Allow to cool thoroughly. Thread a strip of craft wire through the holes. Twist or tie the wire to secure the model bones together. The cylindrical bone, or radius, pivots inside the dip of the ulna. If the model of the pivot joint is too loose, wrap a medium rubber band around the joint areas to increase the tension.

    Things You'll Need

    • Picture of arm bones
    • Modeling clay
    • Cookie sheet
    • 4 large embroidery needles
    • Oven
    • Potholder
    • Thin craft wire
    • 2 rubber bands

Related Articles

6 Types of Freely Movable Joints
How to Make a Model of a Human Ball Socket Joint
How to Build a Knee School Project
Anatomy of the Ligaments in the Forearms
Parts of the Human Heel
What Makes a Skeleton Move?
How to Study the Bones in the Human Skeleton
Description of the Anatomy of a Human Finger
How to Build an Elbow Joint Model
How to Make a Tooth Model for a School Project
How to Create a Human Spine Model for a Science Project
How to Use a Bushnell Voyager Telescope
How to Make a 3D Model of the Muscular System for a...
What Is the Purpose of the Fibrous Capsule?
How Do Worms Move?
How Doorknobs Work as a Simple Machine
How to Make a Plateau With Clay
How to Make a Human Liver Model
How to Make a Skeleton Using Chicken Bones for a School...
How to Measure the Carrying Angle with a Goniometer

Dont Go!

We Have More Great Sciencing Articles!