The shoulder is formed by the bulbous head of the humerus and the shallow glenoid fossa to create the glenohumeral joint (GH). In conjunction with glenohumeral joint, the shoulder blade provides extra range of motion for the shoulder. Of all the joints in the body, the shoulder has the greatest range of motion with six movements.
Flexion
Flexion is when the arm is moving in a straightforward and upward motion. Normal range of motion for flexion of the shoulder joint is 170 to 180 degrees. The motion starts at 0 degrees, or neutral, which is when the arms are at the side of the body with palms facing forward. 180 degrees is when the arms are straight overhead and elbows are by the ears. Anything beyond 180 degrees is considered hyperflexion.
Extension
Extension is when the arm is moving straight backwards. Normal range of motion for extension of the shoulder joint is 50 to 60 degrees. The motion starts at 0 degrees. Shoulder extension is the most powerful shoulder movement.
External Rotation
External rotation occurs when the lower arm rotates outward, away from the body while the elbow remains at the side. Normal range of motion for external rotation is 90 to 100 degrees. For external rotation, 0 degrees is when the upper arm is at the side with the elbows bent 90 degrees. The lower arm is parallel to the floor, and the hand is pointing forward.
Internal Rotation
Internal rotation occurs when the lower arm moves inward, toward the body while the elbow remains at the side. Normal range of motion for internal rotation is 80 to 90 degrees. For internal rotation, 0 degrees is when the upper arm is at the side with the elbows bent 90 degrees. The lower arm is parallel to the floor, and the hand is pointing forward.
Abduction
Abduction is when the arm is moved outward from the side of the body. Normal range of motion for abduction of the shoulder joint is 170 to 180 degrees. The motion starts at 0 degrees, which is when the arms are at the side of the body with palms facing forward. 180 degrees is when the arms are straight overhead and elbows are by the ears.
Adduction
Adduction is moving the limb closer to or across the body. Normal range of motion for adduction is 45 degrees. The motion starts at 0 degrees or neutral, which is when the arms are at the side of the body with palms facing forward. 45 degrees is when the upper arm has moved across the front of the body toward the opposite side.
Considerations
Range of motion can vary depending on joint stability, flexibility, age and muscle contractures.
References
- Rehabilitation Techniques in Sports Medicine, Third Edition; William E. Prentice; 1999
- Evaluation of Orthopedic and Athletic Injuries, 2nd edition; Chad Starkey, Jeff Ryan; 2002
- Kinesiology of the Musculoskeletal System; Donal A. Neuman; 2002
