The elbow joint is a hinge-type synovial joint that connects the upper arm to the forearm.
The elbow isn't just one joint, but a complex of joints working together to allow for flexion, extension, pronation, and supination of the forearm. It primarily functions as a hinge joint, allowing the forearm to bend towards and away from the upper arm.
Here's a breakdown:
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Type of Joint: The elbow is classified as a hinge joint because its primary movement is similar to that of a door hinge - flexion (bending) and extension (straightening). It's also a synovial joint, meaning it has a joint cavity filled with synovial fluid for lubrication and reduced friction.
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Bones Involved: The elbow connects three bones:
- Humerus: The bone of the upper arm.
- Ulna: One of the two bones in the forearm, located on the pinky finger side.
- Radius: The other bone in the forearm, located on the thumb side.
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Movements Allowed:
- Flexion: Bending the forearm towards the upper arm.
- Extension: Straightening the forearm away from the upper arm.
- While the elbow joint primarily facilitates flexion and extension, the surrounding structures also contribute to pronation (rotating the forearm so the palm faces down) and supination (rotating the forearm so the palm faces up). These movements are primarily associated with the radioulnar joints (proximal and distal) located near the elbow.
In summary, the elbow joint is a complex hinge joint that allows for essential movements of the arm and forearm, enabling a wide range of activities.
