In a rotator cuff tear, which tendon is most often torn?

Supraspinatus Tendon Most Commonly Torn

The supraspinatus tendon is the most frequently torn tendon in rotator cuff injuries. 1

Anatomic Vulnerability

The supraspinatus tendon's susceptibility to injury stems from several anatomic and biomechanical factors:

• The supraspinatus occupies a narrow space superiorly in the rotator cuff, with light contact between the tendon and the coracoacromial arch during normal abduction, making it vulnerable to repeated impingement. 1

• Hypovascularity in the region proximal to the supraspinatus insertion contributes to its predisposition to injury and poor healing capacity. 1

• Superior migration of the humeral head occurs with improper rotator cuff functioning and muscle weakness, resulting in direct supraspinatus tendon impingement against the coracoacromial arch. 1

Mechanism of Injury

The supraspinatus is injured through multiple pathways:

• Repetitive eccentric stress placed on the supraspinatus during overhead activities, throwing, and deceleration phases leads to fatigue and eventual tendon failure. 1

• A simple fall can cause acute supraspinatus tears through sudden eccentric loading—the tendon-muscle unit is stretched while simultaneously contracting, with local stresses exceeding the tensile strength of tendon fibers. 2

• The supraspinatus was the most frequently affected tendon in a literature review of 4,061 traumatic rotator cuff tears, with simple falls being the most common cause (725 cases). 2

Clinical Implications

Understanding supraspinatus predominance guides diagnostic approach:

• Supraspinatus tendon impingement is most apparent with the humerus simultaneously abducted and internally rotated, making the Hawkins' test (92% sensitive) and Neer's test (88% sensitive) valuable screening tools. 1

• MRI demonstrates 94% sensitivity and 93% specificity for detecting full-thickness supraspinatus tears, while MR arthrography is superior for partial-thickness articular surface tears. 3

• Diagnostic imaging may miss supraspinatus tears in younger patients—in one series of patients under 25 years, MRI failed to diagnose rotator cuff tears in 50% of cases, highlighting the need for high clinical suspicion in this age group. 4