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Body Joints - Ball and Socket Joint_1.0

Major VersionM

by Suhail Ahanger

Introduction

Using simple plastic materials: a couple of balls, pipe and a waste pen, we make a ball-and-socket joint to represent certain joints in our skeletal system

Video Overview

    • Exercise caution while using scissors/cutter.

    • Work with the lit candle under adult supervision

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  1. Heat a piece of metal wire on a candle and use it to pierce a hole in the small ball
    • Heat a piece of metal wire on a candle and use it to pierce a hole in the small ball

    • Enlarge the hole using a scissor such that it is as big as the diameter of your pencil.

    • Insert one end of the pencil in the hole and glue it in place

    show heating of metal wire and piercing of hole in the small plastic ball.

    Vishal Bhatt - Reply

    • Choose any relatively soft spot on the big ball and make a hole using heated wire

    • Enlarge the hole using a scissor and then a cutter such that the hole is about 2-3mm smaller than the diameter of the small ball.

    • Use a ruler to measure the diameter of the hole made in the big ball.

    • Measure the circumference of the small ball using a piece of thread

    • This will enable us to calculate the diameter of the small ball: divide the number above with pi (= 3.14)

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    • Make another hole on the big ball diametrically opposite the first one using heated wire.

    • Enlarge the hole using scissor/cutter such that the PVC pipe can fit through this hole.

    • Insert the PVC pipe about 3-4 cms inside this hole and glue it in place.

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    • Draw a line between the two previous holes

    • Bisect that line with another line such that it covers about three-quarters of the circumference of the big ball

    • Make a cut along this line using the cutter and/or scissor

    You will notice I have changed the order of steps and added some new instructions in some of the steps. You will need to add some relevant photos to reflect these changes

    Procheta Mallik - Reply

    Based on this, some reordering/reshooting of the video may also be in order. Discuss with Dileep how best to do it and finalise

    Procheta Mallik - Reply

    • Open the 3/4th cut part of the big ball and insert the small ball through it such that the pencil end of the small ball emerges through the bigger hole on the big ball.

    • Now seal the 3/4th cut on the big ball with tape

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    • This now resembles the ball-socket joint of our shoulders .

    • By moving the pencil in all directions like a joystick, you get an idea of how the ball-and-socket joint in our shoulders works.

    You will need to make the bigger hole on the big ball slightly bigger to get better shots of the final model to show a larger degree of movement, as close to 90 degrees as possible.

    Procheta Mallik - Reply

    • Optional material variation is guided using easy to use materials to depict the functions of ball-and-socket joint.

      • Tools: Paper Cutter, Measuring Scale, Cotton Thread, Glue, Scissor, Marker, Insulation tape.

      • Parts: Soft Ball, Polystyrene foam ball, PVC pipe - 15cm, Pencil.

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    • Carefully insert one end of the pencil to the polystyrene foam ball and glue it in place.

      • This resembles the rounded bone part of your ball and socket joint.

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    • Draw a line along the circumference of the ball, such that it covers about three-quarters of the circumference of the big ball.

    • Make a cut along this line using the cutter.

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    • Choose any relatively soft spot on the big ball and make a hole using a cutter.

    • Enlarge the hole using cutter such that the PVC pipe can fit through this hole.

    • Insert the PVC pipe about 3-4 cms inside this hole and glue it in place.

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    • Make another hole on the big ball diametrically opposite the first one using a cutter.

    • Enlarge the hole using a cutter such that the hole is about 2-3 mm smaller than the diameter of the small ball.

      • Use a ruler to measure the diameter of the hole made in the big ball.

    • Measure the circumference of the small ball using a piece of thread

      • This will enable us to calculate the diameter of the small ball: divide the number above with pi (= 3.14)

      • This resembles the socket part of the joint.

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    • Open the 3/4th cut part of the big ball and insert the small ball through it such that the pencil end of the small ball emerges through the bigger hole on the big ball.

    • Now seal the 3/4th cut on the big ball with tape

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    • Your ball and socket joint is ready.

    • By moving the pencil in all directions like a joystick, you get an idea of how the ball-and-socket joint in our shoulders works

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    • Let's try modelling a ball and socket joint a different way.

      • Tools: Paper Cutter, Metal Wire, Candle, Matchbox, Cotton Thread - 15cm, Glue.

      • Parts: Soft Ball, Half cut plastic ball, PVC Pipe (of any size).

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    • Select a relatively soft spot on the soft ball and make a hole using a cutter.

    • Enlarge the hole such that the PVC pipe perfectly fits into the hole and glue it in place.

      • This now resembles the rounded bone part of your joint.

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    • Draw a line along the circumference of the ball using a marker.

    • Using a cutter, make a cut along this line such that you get two halves of the plastic ball.

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    • Heat a piece of metal wire and make two holes at the poles on the plastic ball and soft ball, wide enough to insert the cotton threads into and out.

    • Insert a cotton thread about 15 cm into one hole of the soft ball and out from the other.

    • Now take the open ends of the thread out through each holes made on the plastic ball and tie the ends.

    • Leave enough thread in the between before tying so that the ball moves freely within the socket.

      • You can think of the thread as a way ligaments ( a fibrous connective tissue) work, attaching bone to bone.

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    • The model now resembles the ball and socket joint of your shoulder.

    • Move the PVC pipe like joystick to get an idea of the shoulder movements.

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    • As an additional variation, you can try another optional method of variation in understanding the ball and socket joint of the human body/skeleton.

      • Set a three ounce paper cup in front of you.

      • Roll some clay in your hands into a ball.

        • You want to use about the same amount of clay as it takes to fill the paper cup.

      • Place the clay ball into the paper cup and press the end of a craft stick into the clay.

      • Rotate the craft stick so the ball moves around inside the cup. This is the same way a ball and socket joint rotates.

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    • Make sure the cut on the big ball is long enough such that you can insert the small ball through it

    • The big hole in the big ball should not be bigger than the small ball. It should be about 2-3mm smaller than the diameter of the small ball, no smaller.

    • The pencil should be glued firmly in the small ball, whose hole should not be much larger than the pencil diameter.

    • The PVC pipe should be glued firmly to the big ball, whose smaller hole should be just about the same size as the pipe diameter.

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    • In your science journal draw a picture of the bone movement. Use arrows to show the range of motion for the ball and socket joint.

    • Now that you are familiar with the shoulder movements, based on your observations and using Image 1 as reference, note down the Normal Range of Motion (ROM) in the Table provided.

    • In the skeleton shown (Image 2), can you identify which joint resemblance the ONLY movement of the CCTV camera?Can you identify any such objects around you that have joints in close resemblance as the function of joints in your body?

    • Noticed why the ball and socket joint have the greatest range of motion? Observe the degree of freedom of a ball and socket joint (shoulder joint) compared to a hinge joint (elbow joint).

    • List some advantages and disadvantages of ball and socket joint.

    • Do you enjoy doing physical exercise at school? The next time, observe the range of motion while doing different exercises.

    • Bowl an imaginary ball at an imaginary wicket. How did you move your arm? Did you rotate it at the shoulder in a circular movement? Did you notice the range of function provided by your shoulder joint?

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Finish Line

Suhail Ahanger

Member since: 05/02/2017

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