Download Unit 6 - Perry Local Schools

Unit 6
Joints
Joints of the Skeletal System
• Articulations
- Junctions between bones
• Bind parts of skeletal system together
• Make 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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Joints
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Classifications
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Functionally: by the degree of movement they permit
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Immovable – Synarthrosis
Slightly movable – Amphiarthrosis
Freely movable - Diarthrosis
Structurally: by their anatomy
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Fibrous, cartilaginous, or synovial
Functional Classification
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Types
1.
Synarthrosis: immovable
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2.
Amphiarthrosis: slightly movable
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3.
Pelvis, sutures, teeth, Epiphyseal plate (growth plate)
Tibia-fibula, vertebrae, pelvic symphysis
Diarthrosis: freely movable
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Most joints of the body
All diarthrotic joints are synovial
Structural Classification
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Based on what is between bones:
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Space (or not)
Type of connective tissue present
Types
1.
2.
3.
Fibrous joints - no cavity, dense irregular connective
tissue
Cartilaginous joints - no cavity, bones held together by
cartilage
Synovial joints - synovial cavity, dense irregular tissue
of articular capsule, and often ligaments
Fibrous Joints
3 Types
1. Syndesmosis
2. Suture
3. Gomphosis
1. Syndesmosis
• Long fibers connect bones
• Amphiarthrotic
• Distal ends of tibia and fibula
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Fibrous Joints
Copyright 2010, John Wiley & Sons, Inc.
Fibrous Joints
2. Suture
• Between flat bones
• Synarthrotic
• Thin layer of connective tissue connects bones
3. Gomphosis
• Cone-shaped bony process in a socket
• Tooth in jawbone
• Synarthrotic
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Fibrous Joints
Copyright 2010, John Wiley & Sons, Inc.
Cartilaginous Joints
Symphysis
• Pad of fibrocartilage between bones
• Compressible “shock absorber”
• Amphiarthrotic
•Ex: Intervertebral discs & symphysis
pubis
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Cartilaginous Joints
Copyright 2010, John Wiley & Sons, Inc.
Cartilaginous Joints
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Synchondrosis (synarthrosis)
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Cartilage connects two areas of bone
Example
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Epiphyseal (growth) plate connecting epiphysis and diaphysis
of long bone (synarthrosis)
Cartilaginous Joints
Copyright 2010, John Wiley & Sons, Inc.
Synovial Joints: Structure
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Synovial cavity: Space containing fluid
Articular cartilage
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Covers ends of bones, absorbs shock
Articular capsule
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Inner layer: Synovial membrane secretes synovial fluid
(reduces friction, supplies nutrients)
Outer layer: Dense, irregular connective tissue
Diarthrotic
Synovial Joints: Structure
Copyright 2010, John Wiley & Sons, Inc.
Synovial Joints: Structure

In some cases synovial joints include:
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Ligaments (either inside or outside of joint cavity)
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Joins a bone to another bone
Menisci (cartilage discs)
Articular fat pads
Bursae
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Sacs made of synovial membranes containing fluid
Located where friction can occur
Examples: Between skin-bone, tendons-bones, musclesbones, ligaments-bones
Act as “ball bearings”
General Structure of a Synovial Joint
Synovial fluid = viscous lubricating fluid within cavity
1.
Reduces friction between cartilages of 2 bones
2.
Provide “weeping lubrication”
3.
Nourish cartilage
4.
Contain phagocytes
Skeletal Muscle Actions
• Origin – Immovable end
• Insertion – Movable end
* When muscle contracts & shortens its Insertion is pulled toward its
Origin
• Prime mover (Agonist) – Primarily responsible for movement
• Synergists – Assist prime mover
• Antagonist – Muscle in opposition to the action of the prime mover’s
and cause movement in the opposite direction
•Antagonist relaxes (stretches) during prime movement
•Fixators – Muscle groups that stabilize the origin of the prime mover so
that the prime mover can act more efficiently
Copyright 2010, John Wiley & Sons, Inc.
9-30
Types of Movements at Synovial Joints
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Flexion
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Extension
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Decrease in angle between articulating bones
Increase in angle between articulating bones
Anatomical position the body is in full extension
Hyperextension
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Bending beyond 180o degrees
Moving humerus backwards behind anatomical position
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Movements
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Abduction
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Adduction
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Movement of bone toward midline
Circumduction
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Movement of bone away from midline
Movement of distal end in a circle
Rotation
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Bone revolves around its own longitudinal axis
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Special Movements
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Elevation
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Depression
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Movement downward
Protraction
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Movement upward
Movement forward
Retraction
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Movement backward into anatomical position
Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Special Movements
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Inversion
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Eversion
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Move soles laterally
Dorsiflexion
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Move soles medially
Bend foot toward dorsum (“stand on heels”)
Plantar flexion
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Bend foot toward plantar surface (“stand on toes”)
Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Special Movements at Synovial Joints
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Supination
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Movement of forearm so palms face forward or upward
Pronation
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Movement of forearm so palms face backward or
downward
Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Synovial Joints
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Saddle joints
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One side of saddle-shaped, other like a rider astride it
Ex: Trapezium (carpal) to metacarpal-1 (thumb)
Movements: Triaxial (F, E, ABD, ADD, ROT)
Ball-and-socket joints
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Ball-like surface into cuplike socket surface
Ex: Shoulder, hip
Movements: Triaxial (F, E, ABD, ADD, CIR, ROT)
Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Synovial Joints
Condyloid joints
Convex oval surface to concave oval surface
Ex: Wrist, metacarpophalangeal-2 to -5 joints
Movements: F, E, ABD, ADD
Copyright 2010, John Wiley & Sons, Inc.
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Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Six Types of Synovial Joints
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Planar joints
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Articulating surfaces flat or slightly curved
Ex: Between carpals, tarsals, sternum-clavicle, scapulaclavicle
Movements: Gliding
Hinge joints
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Convex-to-concave surfaces
Ex: Elbow, knee, ankle, interphalangeal
Movements: Flexion (F) and extension (E) only
Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
8-10
Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Types of Synovial Joints
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Pivot joints
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Rounded surface with ring formed by bone and ligament
Ex: Atlantoaxial joint (to turn head to say “no”) and
radius-ulna for pronation-supination
Movement: Rotation (ROT)
Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
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Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc.
Details of a Synovial Joint: Knee Joint
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See slides 10a-d
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Ligaments
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Menisci (medial and lateral)
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Tibial and fibular collateral ligaments
Anterior cruciate ligament (ACL): 70 % of knee injuries
Posterior cruciate ligament (PCL)
Fibrocartilage discs that increase stability of knee joint
Bursae
Arthroplasty
Knee replacement: Total or partial
Knee Joint
Copyright 2010, John Wiley & Sons, Inc.
Knee Joint
Copyright 2010, John Wiley & Sons, Inc.
Knee Joint
Copyright 2010, John Wiley & Sons, Inc.
Knee Joint
Copyright 2010, John Wiley & Sons, Inc.
Aging of Joints
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Decrease in production of synovial fluid
Thinning of articular cartilage
Ligaments shorten and lose flexibility
Influenced by genetic factors
Common Disorders of Joints
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Common joint injuries
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Rotator cuff injury
Separated shoulder
Tennis elbow
Dislocation of the radial head
Knee injuries: Swollen knee, rupture of tibial collateral
ligaments, dislocated knee
Rheumatism: Rheumatoid arthritis, osteoarthritis
Life-Span Changes
• Fontanels of skull harden in first 2 years
• Epiphyseal plates harden from ages 14-20 years
• Fibrocartilage loses water, decreases flexibility of
intervertebral joints and knees
• Collagen changes causes stiffening beginning at age 30
• Joint stiffness is an early sign of aging
• Regular exercise can prevent stiffness
• Fibrous joints first to strengthen over a lifetime
• Changes in symphysis joints of vertebral column diminish
flexibility and decrease height
• Synovial joints lose elasticity
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Clinical Application
Joint Disorders
Sprains
• Damage to cartilage, ligaments, or tendons associated with joints
• Forceful twisting of joint
Arthritis
Bursitis
• Inflamed, swollen, painful joints
• Inflammation of a bursa
• Rheumatoid Arthritis
• Overuse of a joint
• Osteoarthritis
• Gout
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