THE SKELETON

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					THE SKELETON
                 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.
• 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
        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.
                   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.
             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
             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.
• 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.
                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.
• The ankle joint         • The elbow joint
• In the ankle the talus • In the elbow the
  articulates with the      humerus articulates with
  tibia and fibula.         the radius and the ulna.
• Ligaments provide • Movement can only
  stability to the joint.   occur in one plane.
             The pivot joint
• The radio-ulna           • Atlas/axis
• In this joint the radius • In this joint the atlas
  and ulna articulate        and axis bones
  within the elbow joint.    articulate to allow a
• This joint allows the      rotation movement as
  elbow some twisting        in shaking your head.
  movement (pronation &
  supination.
  Condyloid and gliding joints
• The wrist             •   The spine
• In this joint the •       The spine has five areas
  radius and ulna           and has to fulfil many
  bones articulate          functions such as weight
  with 3 of the             bearing stability and
  carpal bones.             support.
  What have you learnt? •   There are three type of joint
  Click here to complete
                            in the spine but for A level
  exercise 1 [Quia]         the main one to know is the
  Click here to open word   gliding joints between the
  document                  vertebral arches.
  Complete and add to
  your notes
         Features of a synovial joint
• Synovial joint have a number of common
  features.
       FEATURE         STRUCTURE                 FUNCTION

Hyaline/articular   Smooth& spongy       •Prevents friction
cartilage           covers ends of bones between articulating
                                         bones
Two layered joint   Outer layer – tough & •To strengthen joint
capsule             fibrous               •To secrete synovial
                    Inner – synovial      fluid
                    membrane covers all
                    internal surfaces
Synovial fluid      Slippery fluid like egg •Reduce friction
                    white which fills joint •Nourish cartilage
                    capsule                 •To get rid of waste
                                            from joint
  FEATURE          STRUCTURE                      FUNCTION

Ligament         A band of strong      •Joins bone to bone
                 fibrous connective    •Provides stability
                 material

Pads of fat      Fatty pad found       •Increases joint stability
                 between capsule,      •Acts as shock absorber
                 bone or muscle        •Reduces friction
Meniscus         A wedge of tough      •Improves fit between bone ends
                 flexible cartilage    •Increases stability
                                       •Reduces wear & tear to joint
                                       surfaces

Bursae           Fluid filled sac      •Reduces friction
                 found between
                 tendon and bone

 Play the matching card game to make sure you know these features
     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:-
      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
      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
     What have you learnt?
Click on the links to review your
            learning

          Walk the plank
         Penalty shoot out
         Fling the teacher
        Crossword exercise

				
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