Fibrous joints are characterized by being held together by dense connective tissue, primarily collagen fibers. These joints offer limited to no movement.
Here's a breakdown of the key structural features:
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Connective Tissue Composition: The primary structural feature is the abundance of dense, irregular connective tissue. This tissue is predominantly composed of strong collagen fibers that tightly bind the articulating bones.
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Absence of a Joint Cavity: Unlike synovial joints, fibrous joints lack a joint cavity or space between the bones. This direct connection contributes to their stability and limited movement.
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Classification Based on Connective Tissue Amount and Length:
- Sutures: Found only in the skull. Short connective tissue fibers tightly interlock the bones. Allow minimal to no movement (synarthrotic).
- Syndesmoses: Bones are connected by longer ligaments or interosseous membranes. Allow for slight movement (amphiarthrotic). Example: distal tibiofibular joint.
- Gomphoses: "Peg-in-socket" fibrous joint. The only example is the articulation of a tooth with its bony alveolar socket. The fibrous connection is the periodontal ligament.
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Limited or No Movement: The dense connective tissue and absence of a joint cavity restrict movement, often classifying these joints as synarthrotic (immovable) or amphiarthrotic (slightly movable).
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High Stability: The tight binding provided by the connective tissue contributes to the overall stability of the joint, protecting it from dislocation or excessive movement.
In summary, fibrous joints are structurally characterized by the direct connection of bones via dense connective tissue, the lack of a joint cavity, and the resultant limited movement, providing stability to the skeletal framework.
