Chapter 8 Joints of the Skeletal System

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Chapter 8Joints of the Skeletal System

• Joint- site where two bones come together
• Articulation functional junctions between bones
• FUNCTIONS OF JOINTS
• Articulations
• Junctions between bones
• Binds parts of skeletal system together
• Makes bone growth possible
• Permit parts of the skeleton to change shape
  during childbirth
• Enable body to move in response to skeletal
  muscle contraction

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Classification of Joints
Structural Classification

• Synovial Joints
• Bones separated by a
• joint cavity
• most complex
• allow free movement
• hip, knee, shoulder

• Fibrous Joints
• Bones held together by connective tissues
• between bones in close contact
• skull sutures and teeth
• no joint cavity

Functional Classification

• Cartilaginous Joints
• Bones held together by cartilage
• pubic symphysis and invertebral discs
• no joint cavity

• Synarthrotic
• immovable
• Amphiarthrotic
• slightly movable
• Diarthrotic
• freely movable

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Fibrous Joints

• 3 Types
• Syndesmosis
• Suture
• Gomphosis

• Syndesmosis
• long fibers connect bones
• amphiarthrotic
• distal ends of tibia and fibula

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Fibrous Joints

• Suture
• between flat bones
• synarthrotic
• thin layer of connective tissue connects bones

• Gomphosis
• cone-shaped bony process in a socket
• tooth in jawbone
• synarthrotic

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Cartilaginous Joints

• 2 Types
• Synchondrosis
• Symphysis

• Synchondrosis
• bands of hyaline cartilage unite bones
• epiphyseal plate (temporary)
• between manubrium and first rib
• synarthrotic

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Cartilaginous Joints

• Symphysis
• pad of fibrocartilage between bones
• pubis symphysis
• joint between bodies of vertebrae
• amphiarthrotic

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Synovial Joints

• Diarthrotic move freely
• joint cavity
• joint capsule
• articular cartilage
• Osteoarthritis
• synovial fluid
• reinforcing ligaments
• fatty pads
• menisci
• bursae flattened fibrous sacs that prevent
  friction

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Synovial fluid

• A lubrication fluid within the joint cavity
• Functions of SF
• Reduces friction between cartilages of 2 bones
• Nourishes cartilage of the joint
• Contains phagocytes
• Provides weeping lubrication

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Types of Synovial Joints

• Condyloid (ellipsoid) Joint
• permit all angular movement, except rotation
• between metacarpals and phalanges
• knee

• Ball-and-Socket Joint
• all angular movement
• hip
• shoulder

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Types of Synovial Joints

• Gliding (plane) Joint
• cartilaginous joints
• intervertebral discs
• between carpals and tarsals

• Hinge Joint
• permit flexion and extension
• only
• elbow
• between phalanges

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Types of Synovial Joints

• Pivot Joint
• permit rotation
• between proximal ends of radius and ulna

• Saddle Joint
• between carpal and metacarpal of thumb

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General Types of Movements

• 1. Gliding movements when flat bones surfaces
  glide or slide over one another
• 2. Angular movements changes in angles between
  bones (synovial joints)
• 3. Special Movements at special joints

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Gliding Movements

• Occur at cartilaginous joints
• Examples
• Intervertebral disc
• Sternoclavicular joint

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Angular Movements

• abduction/adduction
• dorsiflexion/plantarflexion
• flexion/extension/hyperextension

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Angular Movements

• rotation/circumduction

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Special Movements

• eversion/inversion
• protraction/retraction
• elevation/depression
• supination/pronation

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Shoulder Joint

• ball-and-socket
• head of humerus
• glenoid cavity of scapula
• loose joint capsule
• bursae
• ligaments prevent displacement
• very wide range of movement

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Shoulder Joint
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Elbow Joint

• hinge joint
• trochlea of humerus
• trochlear notch of ulna
• gliding joint
• capitulum of humerus
• head of radius
• flexion and extension
• many reinforcing ligaments
• stable joint

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Elbow Joint
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Hip Joint

• ball-and-socket joint
• head of femur
• acetabulum
• heavy joint capsule
• many reinforcing ligaments
• less freedom of movement than shoulder joint

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Hip Joint
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Knee Joint

• largest joint
• most complex
• medial and lateral condyles of distal end of
  femur
• medial and lateral condyles of proximal end of
  tibia
• femur articulates anteriorly with patella
• modified hinge joint
• flexion/extension/little rotation
• strengthened by many ligaments and tendons
• menisci separate femur and tibia
• bursae

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Knee Joint
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Life-Span Changes

• Joint stiffness is an early sign of aging (next
  slide)
• Regular exercise can prevent stiffness
• Fibrous joints first to strengthen over a
  lifetime. Sutures during infancy
• Ligaments lose their elasticity and become
  tightly crossed linked.
• Changes in symphysis joints of vertebral column
  diminish flexibility and decrease height
• Synovial joints start to lose elasticity in
  30s. Affects range of motion and can upset
  balance, contributing to more falls later in
  life.

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Joint Disorders

• Sprains
• damage to cartilage, ligaments, or tendons
  associated with joints
• forceful twisting of joint (slide)

• Bursitis
• inflammation of a bursa
• overuse of a joint

• Arthritis
• inflamed, swollen, painful joints
• over 100 types of arthritis
• involves cartilage, bone, muscles, tendons,
  ligaments,
• and nerves
• 10 of the population
• no cure

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Types of Arthritis

• Rheumatoid Arthritis the synovial membranes of
  the joints and connective tissues grow abnormally
  to form a layer in the joint capsule.
• - this layer grows into the articular surface,
  destroying cartilage and fusing bones of the
  joint.
• Osteoarthritis degenerative joint disease,
  occurs in people in their 70s.
• - more common in overweight people
• - exercise can prevent this disease

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