The glenohumeral joint is the shoulder joint, a ball-and-socket joint that connects the humerus (upper arm bone) to the scapula (shoulder blade). It's a complex articulation between the glenoid fossa of the scapula and the head of the humerus.
Components of the Glenohumeral Joint
- Glenoid Fossa: A shallow socket on the scapula.
- Head of the Humerus: The rounded top of the humerus.
- Glenoid Labrum: A fibrocartilaginous rim that deepens the glenoid fossa, providing more stability.
- Capsule: A fibrous structure surrounding the joint, providing stability and containing synovial fluid.
- Ligaments: Strong bands of tissue that connect the bones and provide support (e.g., glenohumeral ligaments).
- Rotator Cuff Muscles: A group of four muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) that surround the joint and provide dynamic stability and control movement.
Function
The glenohumeral joint allows for a wide range of motion, including:
- Flexion (raising the arm forward)
- Extension (moving the arm backward)
- Abduction (raising the arm away from the body)
- Adduction (bringing the arm towards the body)
- Internal Rotation (rotating the arm inward)
- External Rotation (rotating the arm outward)
- Circumduction (a circular movement)
Importance
The glenohumeral joint's extensive range of motion makes it susceptible to instability and injury. Common problems include dislocations, rotator cuff tears, and arthritis. Proper function of this joint is essential for activities of daily living and athletic performance.
