Fibrous joints are usually immovable.
Fibrous joints are classified as fixed joints, also known scientifically as synarthroses. As the name suggests and the reference confirms, a fibrous joint is where two bones are united by collagenous fibrous connective tissue.
Based on the provided reference, it is stated that fibrous joints are usually immovable and lack a joint cavity. This structure, relying on dense connective tissue to connect bones, limits or entirely prevents movement between the joined bones.
Understanding Fibrous Joints
- Structure: Bones are connected directly by fibrous connective tissue.
- Cavity: They do not possess a joint cavity (a fluid-filled space found in synovial joints).
- Movement: They are primarily characterized by little to no movement.
Types and Movability
While the general characteristic is immovability, there are slight variations in the degree of movement depending on the specific type of fibrous joint.
- Sutures: Found between the bones of the skull. These are tightly interlocked and are completely immovable in adults. An example is the sagittal suture between the parietal bones.
- Syndesmoses: Bones are connected by ligaments or sheets of fibrous tissue, allowing for a slight amount of movement (slightly movable, or amphiarthrosis). An example is the joint between the tibia and fibula at the ankle.
- Gomphoses: Joints where a tooth is anchored into its socket in the jawbone by the periodontal ligament. This is also considered immovable (synarthrosis).
Despite the minor movement in syndesmoses, the overarching classification and the characteristic of lacking a joint cavity place them under the umbrella of fibrous joints, which are, as the reference states, usually immovable.
