What is the normal ROM of internal and external rotation respectively? Ο 180/180 Ο 90/90 Ο 130/130 100/80
The Correct Answer and Explanation is:
The correct range of motion (ROM) for internal and external rotation in the shoulder joint is 90/90. This refers to the typical motion allowed for both internal and external rotation in a healthy, functional shoulder.
Explanation:
The shoulder joint, also known as the glenohumeral joint, has a large range of motion due to its ball-and-socket structure. This allows the arm to move freely in nearly all directions. Internal and external rotations are key movements of the shoulder, often assessed during physical exams or rehabilitation.
- Internal rotation: This is when the front of the arm rotates toward the body. The typical ROM for internal rotation in the shoulder is 90 degrees, though individual variations can occur based on factors like flexibility, shoulder health, and age.
- External rotation: This occurs when the arm rotates outward, away from the body. The normal ROM for external rotation is also typically 90 degrees.
Significance of the 90/90 Range:
- A normal range of 90 degrees for both internal and external rotation is considered optimal for functional activities like reaching, lifting, and throwing.
- Less than 90 degrees of ROM may indicate tightness, weakness, or an issue like a rotator cuff injury, while more than 90 degrees could point to hypermobility, which might also lead to instability or injuries in some cases.
For the shoulder, this 90/90 range is used in both clinical assessments and functional exercises to ensure proper movement mechanics and to prevent injury. Regular assessment can help detect early signs of shoulder dysfunction, aiding in early intervention and treatment.
