Limited range of motion especially in flexion, adduction, and internal rotation. T2-weighted images demonstrates abnormal increased T2 weighted signal at the leading edge of the pectoralis major muscle. The muscle is macerated and retracted. Abnormal increased fluid surrounding the biceps tendon in the intertubercular groove is an associated finding.
Findings are diagnostic of compete tear of the pectoralis major tendon at the insertion site.
Rupture of the tendon occurs when excessive force is applied while the muscle is in maximal eccentric contraction. The injury seems to be most common among weight lifters and high performance athletes, particularly football players. Incomplete ruptures are more common than complete rupture. Clinically, patients present with the characteristic history of excessive muscle stress or a direct blow to the shoulder region while the arm is in abduction and extension. The physical findings are related to the site and type of injury.