The rotator cuff is composed of muscles and tendons that stabilize the upper arm bone within the shoulder socket. Damage to these tendons, often called a tear, causes pain and significant weakness, making everyday activities difficult. This article provides preliminary information on recognizing common indicators of a rotator cuff tear, but it is not a substitute for a comprehensive medical evaluation.
Anatomy and Common Causes of Tears
The rotator cuff is composed of four muscles: the supraspinatus, infraspinatus, teres minor, and subscapularis. These structures center the head of the humerus (upper arm bone) within the shoulder socket and control the arm’s rotational and lifting movements. The supraspinatus is instrumental in the initial lifting motion of the arm away from the body.
Tears occur through two primary mechanisms: acute injury or degenerative wear. An acute tear happens suddenly, often due to trauma like a fall onto an outstretched arm or lifting a heavy object with a jerking motion. Degenerative tears, also known as chronic tears, develop slowly over time due to repeated stress and natural wearing down of the tendon tissue. This gradual breakdown is common in individuals over 40 and those who perform repetitive overhead activities.
Identifying Subjective Pain and Movement Patterns
A primary sign of a potential tear is the quality and location of the pain. Discomfort is felt over the outer part of the shoulder and may radiate downward into the upper arm, typically stopping above the elbow. This pain intensifies when the arm is lifted or moved, suggesting the injured tendon is compressed during motion.
Pain often disrupts sleep, especially when lying directly on the affected shoulder. Specific movements trigger discomfort, such as reaching behind the back to tuck in a shirt or fastening a seatbelt. A sharp, painful sensation when the arm is lifted out to the side, particularly between 60 and 120 degrees of movement, is often reported. This range of motion is referred to as the painful arc, indicating the tendon may be pinched as it moves beneath the bone.
Performing At-Home Strength and Mobility Checks
Noticeable weakness or an outright inability to perform specific, controlled movements is a strong indicator of a rotator cuff tear. The inability to sustain a held position against gravity during any of these targeted movements is a strong indicator of muscular or tendinous damage.
Drop Arm Test (Supraspinatus)
The Drop Arm Test is a useful self-check, primarily targeting the integrity of the supraspinatus tendon. To perform this, lift the arm out to the side as high as possible, then try to slowly and smoothly lower it back down to the side. A positive sign is the inability to control the descent, resulting in the arm suddenly dropping, or the inability to lift the arm past 90 degrees without significant pain. This uncontrolled drop suggests that the muscle responsible for initial arm elevation is compromised.
External Rotation Lag Sign (Infraspinatus and Teres Minor)
To check the muscles responsible for external rotation, hold the affected arm close to the side and the elbow bent to 90 degrees. Passively rotate the forearm as far outward as possible. Attempt to hold this outward rotation position without any external support. If the forearm immediately springs or “lags” back toward the abdomen, it indicates that the muscles providing the holding power for external rotation have failed.
Lift-Off Test (Subscapularis)
The Lift-Off Test assesses the subscapularis muscle, which manages internal rotation. Place the back of the hand against the mid-portion of your lower back, as if reaching into a back pocket. Try to actively lift the hand away from the back without letting the elbow move backwards. If the hand cannot be lifted away from the back, or if lifting requires significant compensating movements of the shoulder blade or trunk, it suggests subscapularis dysfunction.
Next Steps and Seeking Professional Confirmation
After performing a self-assessment, any persistent pain, weakness, or inability to move the shoulder warrants a consultation with a healthcare professional. There are certain red flags that should prompt immediate medical attention, such as sudden, complete loss of function in the arm or severe, unrelenting pain following a trauma.
A physician will confirm the diagnosis through a physical examination and imaging studies. An X-ray is used to rule out bone issues, while an MRI or ultrasound visualizes the soft tissues to confirm the presence and size of a tear. While waiting for an appointment, initial management typically involves rest, applying ice to the affected area to reduce inflammation, and using over-the-counter anti-inflammatory medications. Early professional diagnosis is important for determining the most appropriate treatment plan, which may range from physical therapy to surgical repair.