A hinge elbow refers to the elbow joint, which is a type of synovial joint that functions primarily like a hinge. This allows for movements like bending and straightening the arm.
Understanding the Elbow Joint
The elbow is not just a single joint, but a complex articulation involving three bones:
- Humerus: The bone in 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.
Key Articulations
The elbow joint is primarily a synovial hinge joint formed by the articulations between the distal humerus and the proximal ulna. However, other articulations contribute to its function:
- Humeroulnar Joint: This is the main hinge joint, allowing for flexion and extension.
- Humeroradial Joint: The articulation between the humerus and radius, also contributing to flexion and extension.
- Radioulnar Joint (Proximal): This joint, located near the elbow, allows for pronation and supination (rotation of the forearm).
Function
The primary function of the hinge elbow is to allow the arm to bend (flexion) and straighten (extension). This is crucial for a wide range of daily activities, from lifting objects to performing intricate hand movements.
