JointsJoints

Different Kinds of JointsDifferent Kinds of Joints

•Your skeleton is made up of bones.Your skeleton is made up of bones.

• Joints are where the bones meet.Joints are where the bones meet.

•They are divided into three types They are divided into three types depending on how freely the depending on how freely the bones can move.bones can move.– Fixed or immoveableFixed or immoveable– Slightly moveableSlightly moveable– Freely moveable/SynovialFreely moveable/Synovial

Fixed or Immoveable Fixed or Immoveable JointsJoints•The bones at an immoveable joint The bones at an immoveable joint

cant move at all.cant move at all.

•They interlock or overlap, and are They interlock or overlap, and are held close together by tough fibre.held close together by tough fibre.

•The joints between the plates in The joints between the plates in the cranium are a good example.the cranium are a good example.

•Examples are in the cranium and Examples are in the cranium and sacrum.sacrum.

• Gaps called Gaps called fontanelles fontanelles between plates in between plates in the cranium allow the cranium allow a baby’s head to a baby’s head to squash during squash during birth.birth.

• Twelve months Twelve months later the gaps will later the gaps will have closed and have closed and fixed joints will fixed joints will have started to have started to form.form.

Slightly Moveable JointsSlightly Moveable Joints

• They only allow a little bit of movement.They only allow a little bit of movement.• They are held together by strong white cords or They are held together by strong white cords or

straps called ligaments and joined by cartilage.straps called ligaments and joined by cartilage.• Cartilage is a gristly cushion which is on the ends Cartilage is a gristly cushion which is on the ends

of bone and stops them from wearing away.of bone and stops them from wearing away.• The joints in your vertebrae are slightly The joints in your vertebrae are slightly

moveable.moveable.• It has cartilage pads between them which act as It has cartilage pads between them which act as

shock absorbers so the bones won’t jar when you shock absorbers so the bones won’t jar when you run and jump. run and jump.

• Other examples include the joints between your Other examples include the joints between your ribs and sternum. These move a little when you ribs and sternum. These move a little when you breathe in and out.breathe in and out.

Freely Moveable JointsFreely Moveable Joints

•They can move quite freely. (knee joint)They can move quite freely. (knee joint)•A freely moveable joint has these parts:A freely moveable joint has these parts:• Joint CapsuleJoint Capsule•Synovial membrane with synovial fluidSynovial membrane with synovial fluid• Joint cavityJoint cavity•CartilageCartilage•LigamentsLigaments•They are also called synovial joints.They are also called synovial joints.

Cartilage & LigamentsCartilage & Ligaments

•CartilageCartilage – protects bones and – protects bones and stops them knocking together. It stops them knocking together. It forms a gristly cushion between forms a gristly cushion between bones at slightly moveable joints.bones at slightly moveable joints.

•LigamentsLigaments – connect bone to bone. – connect bone to bone. They are elastic enough to allow They are elastic enough to allow movement. Too much movement movement. Too much movement and they would tear your flesh.and they would tear your flesh.

Synovial Synovial JointsJoints

Using joint sheet!!Using joint sheet!!

The ball-and-socket jointThe ball-and-socket joint

•Most moveable joint.Most moveable joint.

•One bone has a bulge like a ball One bone has a bulge like a ball at the end. This fits into a at the end. This fits into a socket in the other bone.socket in the other bone.

• It can turn in many directions It can turn in many directions (hip/shoulder). (hip/shoulder).

The Hinge JointThe Hinge Joint

•Works like a hinge on a door.Works like a hinge on a door.

•The bone can swing back and The bone can swing back and forward.forward.

•The end of one bone is shaped The end of one bone is shaped like a spool of thread and fits like a spool of thread and fits into a hollow in the other.into a hollow in the other.

•The joint opens until straight, The joint opens until straight, but no further. (elbow/knee)but no further. (elbow/knee)

The Pivot JointThe Pivot Joint

•One bone has a bit that juts out, like a One bone has a bit that juts out, like a peg or a ridge. This fits into a ring or peg or a ridge. This fits into a ring or notch on the other bone.notch on the other bone.

•The joint only allows rotation. (neck)The joint only allows rotation. (neck)

The Saddle JointThe Saddle Joint

•The ends of the bone are shaped like The ends of the bone are shaped like saddles and fit snugly together.saddles and fit snugly together.

• It allows movement back and forward It allows movement back and forward and from side to side (thumb).and from side to side (thumb).

The Condyloid JointThe Condyloid Joint

•A rounded bump on one bone A rounded bump on one bone sits in a hollow formed by sits in a hollow formed by another bone or bones.another bone or bones.

•The joint allows movement back The joint allows movement back and forward and from side to and forward and from side to side.side.

•Ligaments prevent bones from Ligaments prevent bones from rotating (joint at wrists)rotating (joint at wrists)

The Gliding JointThe Gliding Joint

•Here the ends of the bones are Here the ends of the bones are flat enough to glide over each flat enough to glide over each other.other.

•There is little movement in all There is little movement in all directions.directions.

•This joint gives the least amount This joint gives the least amount of movement (carpals/tarsal in of movement (carpals/tarsal in the hand and foot).the hand and foot).

Joint Joint MovementsMovements

MovemeMovementnt

DefinitioDefinitionn

ExampleExample SportSport SituationSituation

FlexionFlexion Bending a Bending a part of your part of your body.body.

ExtensionExtension StraighteninStraightening a part of g a part of your body.your body.

AbductionAbduction A sideways A sideways movement movement of a limb of a limb away from away from your body.your body.

AdductionAdduction A sideways A sideways movement movement towards the towards the centre line centre line of your of your body.body.

RotationRotation Turning Turning movement movement around an around an imaginary imaginary line.line.

Circumd-Circumd-uctionuction

End of a End of a bone bone moving in a moving in a circle.circle.