From the Guidelines
The rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis, often remembered by the acronym "SITS". These muscles play a crucial role in stabilizing the shoulder joint and enabling a wide range of motion. The supraspinatus muscle is responsible for lifting the arm sideways, while the infraspinatus and teres minor muscles rotate the arm outward, and the subscapularis muscle rotates the arm inward 1.
The rotator cuff muscles originate on the scapula and attach to the humerus via tendons, which can be prone to injury due to overuse, trauma, or age-related degeneration. According to a study published in the American Family Physician, rotator cuff tendinopathy affects one in 50 adults and is particularly common in athletes who throw repetitively and in laborers who have to work with their arms overhead 1.
Key functions of the rotator cuff muscles include:
- Stabilizing the shoulder joint by keeping the head of the humerus firmly positioned in the glenoid cavity of the scapula
- Enabling a wide range of motion in the shoulder
- Preventing impingement syndrome and other conditions that can impact shoulder function and mobility
- Working together to maintain joint integrity during movement, which is crucial due to the inherently unstable design of the shoulder joint 1.
In clinical practice, understanding the anatomy and function of the rotator cuff muscles is essential for diagnosing and treating conditions like tendinitis, tears, or impingement syndrome, which can significantly impact a patient's quality of life and mobility.
From the Research
Rotator Cuff Muscles
The rotator cuff muscles are a group of muscles and tendons that surround the shoulder joint, providing dynamic stability and enabling a wide range of motions. The muscles that make up the rotator cuff include:
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
Function and Importance
These muscles work together to provide dynamic stability to the shoulder joint, allowing for movements such as abduction, external rotation, and internal rotation 2. The rotator cuff muscles also help to maintain the balance of forces around the shoulder joint, which is critical for proper joint function and preventing joint damage 3, 4.
Muscle Interactions
The interactions between the rotator cuff muscles are complex, and each muscle plays a unique role in maintaining joint stability and enabling movement. For example, the supraspinatus and infraspinatus muscles work together to provide external rotation, while the subscapularis muscle helps to provide internal rotation 5. The teres minor muscle also plays a role in external rotation and helps to stabilize the joint.
Clinical Significance
Understanding the anatomy and function of the rotator cuff muscles is important for diagnosing and treating rotator cuff injuries and disorders. Rotator cuff tears are a common cause of chronic shoulder pain and disability, and treatment options may include physical therapy, corticosteroid injections, and surgery 2, 6. Preserving the balance of the rotator cuff muscles is critical for maintaining proper joint function and preventing further injury 3, 4.