1. Rotator Cuff Injuries

By Michael S. Erickson, MD

A person with a rotator cuff injury may experience shoulder pain, especially at night, and shoulder weakness.

The rotator cuff muscles extend from the scapula (shoulder blade) and attach to the top of the humerus (upper arm bone). 

At the top of the humerus, these muscles and their tendons blend together, creating a “cuff” around the shoulder’s ball-and-socket joint.

The rotator cuff is prone to injuries. The injuries can be acute or chronic.

• Acute injuries are tears and strains to the rotator cuff that result from a one-time traumatic event, such holding out the arm to break a fall. With rest and proper treatment, these injuries may heal over time.
• Chronic injuries are injuries that result from overuse (fatigue) or entrapment (impingement) of the rotator cuff, or a combination of these factors. Athletes, such as baseball pitchers, and construction workers are especially prone to chronic rotator cuff injuries. These chronic conditions are ongoing, with symptoms lasting 6 weeks or longer.
Most rotator cuff injuries are treated with a combination of pain control, rest, and rehabilitation. More severe injuries may respond better with injections and possibly surgery.
Learn more about the symptoms of a rotator cuff injury, how a rotator cuff injury is diagnosed, and about potential treatments, including injections.
In This Article:
• Rotator Cuff Injuries 
• How Do Rotator Cuff Injuries Occur?
• Rotator Cuff Injuries: Symptoms
• Rotator Cuff Injuries: Causes and Risk Factors
• Rotator Cuff Injuries: Diagnosis
• Rotator Cuff Injuries: Initial Treatment
• Rotator Cuff Injections
• Rotator Cuff Repair Surgery

Rotator Cuff Anatomy

The rotator cuff muscles begin, or originate, at the scapula (shoulder blade) and converge at the bulbous head of the humerus (upper arm bone).
The four muscles involved in the rotator cuff are the:
• Subscapularis, at the front of the shoulder
• Supraspinatus, at the top of the shoulder
• Infraspinatus, at the back of the shoulder
• Teres minor, also located at the back of the shoulder, below the infraspinatus
When working properly, these muscles:
• Help the shoulder move smoothly throughout its nearly 180 degrees of mobility freedom
• Stabilize the shoulder’s ball-and-socket joint by hugging the relatively large humeral head (ball) to the comparatively small glenoid bone (socket)
An injury to the rotator cuff affects the shoulder joint’s stability and range of movement.