THE SKELETON

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THE SKELETON
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Objectives

• Identify the bones that articulate at different
  joints in the body.
• Name the 6 types of synovial joint and give
  examples of each.
• Describe the structure and function of parts of a
  synovial joint.
• Be able to classify joints according the movement
  they allow.
• Use technical language to describe common joint
  movements.
• Analyse sporting techniques in terms of joint
  movements.

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• The human skeleton consists of 206 bones. Many of
  which move or hinge at joints. In conjunction
  with over 600 muscles these bones enable the
  human body to achieve a variety of movements.
• The functions of the skeletal system include -
• To provide a lever system against which muscles
  can pull.
• To provide a large surface area for the
  attachment of muscles.
• To protect delicate organs such as the brain.
• To give shape to the body.
• To give support to the body.
• To manufacture red blood cells and to store fat
  calcium and phosphate.
• Click here- label the skeleton and print it out
  for you file

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AXIAL APPENDICULAR SKELETON

• The bones of the body are grouped into two major
  divisions.
• The axial skeleton consists of the bones, which
  lie around the longitudinal axis of the body.
  These include the SKULL, VERTEBRAL COLUMN,
  STERNUM RIBS.
• The appendicular skeleton consists of the bones
  of the LIMBS, PECTORAL (shoulder) GIRDLE,
  PELVIC (hips) GIRDLE.

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JOINTS

• Joints are where two or more bones articulate
  (move).
• Joints are classified according to how much
  movement they allow.
• 1. Fibrous these are fixed or immovable joints
  such as the cranium, sacrum and the coccyx.
• 2. Cartilaginous these are slightly movable
  joints such as the vertebrae.
• 3. Synovial these are freely movable joints
  such as the shoulder and hip.

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Synovial joints

• In PE these are the most important joints.
• There are 6 types of synovial joint.
• 1. Ball socket hip and shoulder.
• 2. Hinge knee, elbow and ankle.
• 3. Pivot radio-ulna, atlas/axis.
• 4. Saddle thumb.
• 5. Condyloid wrist.
• 6. Gliding between vertebrae in spine.
• Click here and complete the matching exercise

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Ball socket joints

• The hip joint
• The head of the femur fits into a deep cavity
  called the acetabulum on the pelvic bone.
• This deep cavity gives the hip joint stability.
• The presence of strong ligaments add to the
  stability making it difficult to dislocate the
  hip.

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• The shoulder joint
• The head of the humerus fits into a shallow
  cavity on the scapula called the glenoid fossa.
• The shoulder is the most mobile joint in the body
  but is also fairly unstable because of the
  shallow cavity.
• Stability is improved by ligaments and muscles.

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Hinge Joints

• The knee joint
• In the knee joint the femur articulates with the
  tibia.
• The patella (knee cap) helps to give a better
  angle of pull.
• The fibula is not part of the knee joint and so
  the tibia is the weight bearing bone.

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• The elbow joint
• In the elbow the humerus articulates with the
  radius and the ulna.
• Movement can only occur in one plane.

• The ankle joint
• In the ankle the talus articulates with the tibia
  and fibula.
• Ligaments provide stability to the joint.

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The pivot joint

• The radio-ulna
• In this joint the radius and ulna articulate
  within the elbow joint.
• This joint allows the elbow some twisting
  movement (pronation supination.

• Atlas/axis
• In this joint the atlas and axis bones articulate
  to allow a rotation movement as in shaking your
  head.

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Condyloid and gliding joints

• The spine
• The spine has five areas and has to fulfil many
  functions such as weight bearing stability and
  support.
• There are three type of joint in the spine but
  for A level the main one to know is the gliding
  joints between the vertebral arches.

• The wrist
• In this joint the radius and ulna bones
  articulate with 3 of the carpal bones.

What have you learnt? Click here to complete
exercise 1 Quia Click here to open word
document Complete and add to your notes
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Features of a synovial joint

• Synovial joint have a number of common features.

FEATURE STRUCTURE FUNCTION
Hyaline/articular cartilage Smooth spongy covers ends of bones Prevents friction between articulating bones
Two layered joint capsule Outer layer tough fibrous Inner synovial membrane covers all internal surfaces To strengthen joint To secrete synovial fluid
Synovial fluid Slippery fluid like egg white which fills joint capsule Reduce friction Nourish cartilage To get rid of waste from joint
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FEATURE STRUCTURE FUNCTION
Ligament A band of strong fibrous connective material Joins bone to bone Provides stability
Pads of fat Fatty pad found between capsule, bone or muscle Increases joint stability Acts as shock absorber Reduces friction
Meniscus A wedge of tough flexible cartilage Improves fit between bone ends Increases stability Reduces wear tear to joint surfaces
Bursae Fluid filled sac found between tendon and bone Reduces friction
Play the matching card game to make sure you know
these features
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Movements around a joint

• All synovial joints can move freely but the
  amount and type of movements which occur at each
  joint varies.
• Many of the movements occur in pairs they are
  the opposite of each other.
• Technical terms to describe the movements you
  need to know include-

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TERM MEANING
FLEXION A decrease in the angle that occurs in a joint
EXTENSION An increase in the angle which occurs at a joint
ABDUCTION Movement away from the midline of the body
ADDUCTION Movement towards the midline of the body
ROTATION Movement of a bone around its axis (can be inward (medial) or outward (lateral))
CIRCUMDUCTION Lower end of bone moves around in a circle
LATERAL FLEXION Bending sideways
PLANTAR FLEXION Pointing the foot downwards
DORSIFLEXION Bending the foot upwards towards tibia
PRONATION Facing the palm of the hand down
SUPINATION Facing the palm of the hand up
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JOINT POSSIBLE MOVEMENTS
SHOULDER Flexion extension, adduction abduction, circumduction, rotation
ELBOW Flexion extension
RADIO-ULNA Pronation supination
WRIST Flexion extension, adduction abduction, circumduction
SPINE Flexion extension, lateral extension, rotation
HIP Flexion extension, adduction abduction, circumduction
KNEE Flexion extension
ANKLE Dorsiflexion plantaflexion
Click on the link to complete the exercise
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What have you learnt?Click on the links to
review your learning

• Walk the plank
• Penalty shoot out
• Fling the teacher
• Crossword exercise