A systematic review and comprehensive classification of pectoralis major tears

Reported descriptions of pectoralis major (PM) injury are often inconsistent with the actual musculotendinous morphology. The literature lacks an injury classification system that is consistently applied and accurately reflects surgically relevant anatomic injury patterns, making meaningful comparison of treatment techniques and outcomes difficult.

Published cases of PM injury between 1822 and 2010 were analyzed to identify incidence and injury patterns and the extent to which these injuries fit into a classification category. Recent work outlining the 3-dimensional anatomy of the PM muscle and tendon, as well as biomechanical studies of PM muscle segments, were reviewed to identify the aspects of musculotendinous anatomy that are clinically and surgically relevant to injury classification.

We identified 365 cases of PM injury, with 75% occurring in the last 20 years; of these, 83% were a result of indirect trauma, with 48% occurring during weight-training activities. Injury patterns were not classified in any consistent way in timing, location, or tear extent, particularly with regard to affected muscle segments contributing to the PM's bilaminar tendon.

A contemporary injury classification system is proposed that includes (1) injury timing (acute vs chronic), (2) injury location (at the muscle origin or muscle belly, at or between the musculotendinous junction and the tendinous insertion, or bony avulsion), and (3) standardized terminology addressing tear extent (anterior-to-posterior thickness and complete vs incomplete width) to more accurately reflect the musculotendinous morphology of PM injuries and better inform surgical management, rehabilitation, and research.