Complete Pectoralis Major Tendon Rupture With Bony Avulsion in an Adolescent Male: A Case Report and Literature Review

Abstract

Pectoralis major (PM) tendon ruptures are rare. Typically, they are caused by eccentric contractions from weight lifting. Due to the rarity of pectoralis major tendon ruptures, clinicians might misdiagnose this condition. We report a 16-year-old male with a right pectoralis major tendon rupture and an avulsion fracture after falling on a grass field playing soccer. He was initially misdiagnosed with biceps tendonitis, which highlights the importance of including pectoralis major tendon ruptures in one's differential diagnoses.

Keywords: avulsion fracture; pec major; pectoralis major; pectoralis major tendon; pectoralis major tendon rupture.

Figure 1. Right AP shoulder X-ray indicating heterotopic ossification at the proximal anteromedial shoulder measuring approximately 7.5 cm in length and 1.3 cm in thickness.

The patient was diagnosed with biceps tendonitis at this time. AP: anteroposterior

Figure 2. Right axial pectoral MRI indicating a bony fragment lateral to the biceps tendon with fluid at its insertion point.

Figure 3. Axial pectoral MRI showing the contralateral (left) side with intact tendon and bony fragment adjacent to the right biceps with no tendinous attachment to the humerus.

Figure 4. Bone mass attached to the pectoralis major.

Figure 5. Four-centimeter resected bone avulsion.

Figure 6. One week status post surgery of right AP shoulder X-ray indicating three lucenies in the right proximal humerus at the site of the suture anchors.

The large, calcified body is no longer visible. AP: anteroposterior