Chapter 8
Joints of the Skeletal System
• Articulations
• Functional 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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Classification of Joints
• Fibrous Joints
• dense connective tissues connect
bones
• between bones in close contact
• Cartilaginous Joints
• hyaline cartilage or
fibrocartilage connect bones
• synarthrotic
• immovable
• amphiarthrotic
• slightly movable
• diarthrotic
• freely movable
• Synovial Joints
• most complex
• allow free movement
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Fibrous Joints
•Held together by
dense connective
tissue
•Interosseous
membrane
•Interosseous
ligament
3 Types
• Syndesmosis
• Suture
• Gomphosis
Syndesmosis
•a sheet or bundle of
fibrous tissue connects
bones
• amphiarthrotic
• lies between 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
•Connected by
hyaline cartilage or
fibrocartilage
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 adjacent vertebrae
• amphiarthrotic
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2
Synovial Joints
•Most common type
of joint
• diarthrotic
•More complex
structurally
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General structure of a synovial
joints
•Articular cartilage
•Joint (articular) capsule
•Outer layer
•ligaments
•Inner layer - synovial
membrane
•synovial cavity
•synovial fluidlubricates and
protects joint
•Menisci-pad of cartilage
• bursae-fluid filled sac
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Types of Synovial Joints
Ball-and-Socket Joint
Condyloid Joint
• hip
• shoulder
•Allow the greatest degree of movement
• between metacarpals
and phalanges
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3
Types of Synovial Joints
Gliding Joint
• between carpals
• between tarsals
Hinge Joint
• elbow
• between phalanges
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Types of Synovial Joints
Pivot Joint
• between proximal
ends of radius and
ulna
Saddle Joint
• between carpal and
metacarpal of thumb
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Types of Joint Movements
• abduction/adduction-moving away
from midline/moving toward the
midline of the body
• dorsiflexion/plantarflexion-moving
toes toward shin/pointing toes down
• flexion/extension/hyperextensiondecreasing the angle between two
bones/increasing the angle between two
bones/extending the joint past the
anatomical position
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4
Types of Joint Movements
• rotation/circumduction-rotating
around a point/moving a
structure in a circle
• supination/pronation-rotating a
structure laterally/rotating a
structure medially
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Types of Joint Movements
• eversion/inversion-rotating toes inward/rotating toes outward
•protraction/retraction-moving a structure anteriorly/moving a structure
posteriorly
• elevation/depression-moving a structure superiorly/moving a structure
inferiorly
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Life-Span Changes
•Fontanels close at 2, 3, 12, 18 - 24 months
•Fibrous joints strength with age
•Joint stiffness is an early sign of aging
•Fibrous joints first to change; can strengthen
over a lifetime
• Changes in symphysis joints of vertebral
column diminish flexibility and decrease
height
• Synovial joints lose elasticity
• Disuse hampers the blood supply
• Activity and exercise can keep joints
functional longer
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5
Clinical Application
Joint Disorders
Sprains
• damage to cartilage, ligaments, or tendons associated
with joints
• forceful twisting of joint
Bursitis
• inflammation of a bursa
• overuse of a joint
Arthritis
• inflamed, swollen, painful joints
• Rheumatoid Arthritis
• Osteoarthritis
• Gout
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Clinical Application
Joint Disorders
Dislocations
• bones in a joint are displaced from their normal position
Torn Cartilage
• meniscus tares
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