Joint Summary

Articulations or Joints
• Articulation or Joint

– Place where two bones (or bone and cartilage) come together – Can be freely movable, have limited, or no apparent movement – Structure correlated with movement

• Naming Joints
– According to bones or parts united at joint- temporomandibular – According to only one of articulating bones- humeral – By Latin equivalent of common name- cubital
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Classes of Joints
• Structural: based on major connective tissue type that binds bones
– Fibrous – Cartilaginous – Synovial

• Functional: based on degree of motion
– Synarthrosis: non-movable – Amphiarthrosis: slightly movable – Diarthrosis: freely movable
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Fibrous Joints
• Characteristics

– United by fibrous connective tissue – Have no joint cavity – Move little or none

• Types: Sutures, Syndesmoses, Gomphoses

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Fibrous Joints: Sutures

• Opposing bones interdigitate. • Periosteum of one bone is continuous with the periosteum of the other. • Sutural ligament: two periostea plus dense, fibrous, connective tissue between. • In adults may ossify completely: synostosis. • Fontanels: membranous areas in the suture between bones. Allow change in shape of head during birth and rapid growth of the brain after birth.
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Fibrous Joints: Syndesmoses
• Bones farther apart than suture and joined by ligaments • Some movement may occur • Examples: radioulnar (interosseus membrane)

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Fibrous Joints: Gomphoses
• Specialized joints • Pegs that fit into sockets • Periodontal ligaments: hold teeth in place • Inflammations
– Gingivitis leads to… – Periodontal disease

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Cartilaginous Joints

• Unite two bones by means of cartilage • Types
– Synchondroses: hyaline cartilage – Symphyses: fibrocartilage

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Cartilaginous Joints: Synchondroses
• Joined by hyaline cartilage • Little or no movement • Some are temporary and are replaced by synostoses • Some are