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Figure. Axial magnetic resonance imaging scan.
A 36-year-old man presents with pain and deformity of his left upper chest 1 week after injuring himself at the gym. He first experienced pain when he was bench pressing weights at the gym; he had just increased the weight and when he started to lift the bar he felt a popping sensation in his left armpit area. He reports he had immediate pain and had to have the bar lifted from him. He felt as though someone had dropped a weight on him. Pain and spasm subsequently ensued in the chest and upper arm area. He was seen at an urgent care center and radiographs were taken but did not show any acute abnormalities.
On physical examination, there is obvious asymmetry to the chest muscles; the left side is larger than the right. There is extensive ecchymosis in the left upper arm and tenderness to palpation of the left chest and axilla. A magnetic resonance imaging (MRI) scan is taken of the axial region (Figure).
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The pectoralis major (pec major) is a broad fan-shaped muscle that originates at the clavicular and sternal heads. The pec major fibers converge into a 5-cm flat tendon that inserts on the humerus at the lateral and distal aspect of the bicipital groove.1 The main function of the pec major is adduction and internal rotation of the humerus, the same maneuver needed to complete a bench press. A pec major tear is a rare injury that occurs almost exclusively in men aged 20 to 40 years who lift weights.1
Pec major tears are often associated with a popping sensation in the upper arm, localized ecchymosis, asymmetry of chest muscles, and muscle weakness.1 The muscle deformity can be enhanced with resisted adduction as the torn muscle belly retracts medially. MRI is the study of choice to diagnose tears if there is any clinical suspicion.1
Most patients with a pec major tendon tear will elect for surgical repair instead of accepting a residual deformity to the chest wall and chronic chest weakness. Surgical repair has a high success rate and typically allows patients to return to a preinjury level of strength and motion. Athletes can expect a return to full participation in activity 3 months postoperatively.2
References
- Petilon J, Carr DR, Sekiya JK, Unger DV. Pectoralis major muscle injuries: evaluation and management. J Am Acad Orthop Surg. 2005;13(1):59-68. doi:10.5435/00124635-200501000-00008
- Nute DW, Kusnezov N, Dunn JC, Waterman BR. Return to function, complication, and reoperation rates following primary pectoralis major tendon repair in military service members. J Bone Joint Surg Am. 2017;99(1):25-32. doi:10.2106/JBJS.16.00124
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