The pectoralis muscle and tendon originates from the chestwall and clavicle and inserts into the humerus.
This is a very powerful muscle and flexes, internally rotates and adducts the humerus. A tear of the tendon mainly occurs in power sports. A painful snap is felt at the front of the shoulder and chest; brusing and swelling is common. Surgical repair is the recommended treatment and restores over 90% of the strength compared to 50% when not repaired. Unfortunately complications are common. Deep and superficial infections and stiffnes are observed in 10% and the reported re-rupture rate is 20%.