Pectoralis Major Tendon Tears: Overview

Pectoralis Major Tendon Tears: Overview

The pectoralis major is the largest muscle of the chest. Often referred to as the "pec" muscle, the pectoralis major is made up of 3 sections that attach to the collarbone, or clavicle; breastbone, or sternum; and lower ribs and abdominals. All parts of the muscle join at the pectoralis major tendon that attaches to the upper arm bone, or humerus. The pectoralis major keeps the arm close to the body and rotated inward. It is the main muscle involved in pushing with the arms and is needed for athletic movements such as push-ups and bench pressing.

Because the pectoralis major is such a powerful muscle, injuries are not that common, although injury rates are increasing due to increased participation in sports and weightlifting. Injuries most often affect the pectoralis major tendon, either where the tendon attaches to the upper arm bone or where the muscle attaches to the tendon. Pectoralis major tendon tears are most often seen in males between the ages of 20 and 40 and are most often associated with athletic or exercise-related injuries. The most common way to tear the pectoralis major tendon is through the bench press, particularly on the lowering part of the movement.

The bench-pressing position places the most stress on the tendon, as the muscle is greatly stretched when the arm is positioned out to the side, with the elbow moving back behind the body under the pressure of heavy weight. Less commonly, pectoralis major tendon tears can occur with contact sports like football, wrestling and boxing, or with heavy lifting performed during work activities. Overuse of the muscle without enough rest, as well as use of anabolic steroids, can increase the risk of tendon injury. At the time of injury, patients will often feel a pop, followed by pain, swelling, and weakness in the arm.

To diagnose a pectoralis major tendon tear, a health care provider will ask a patient how the injury occurred. They will examine the patient's chest and shoulder, looking for signs of uneven appearance or swelling and bruising around the upper arm or chest. They will also test the patient's arm and chest strength. To confirm a diagnosis, a health care provider will likely order imaging studies. While x-rays cannot be used to see if there is a tendon tear, they may be performed to make sure that the upper arm bone is not broken or dislocated. An MRI is the preferred imaging method to be able to see the pectoralis major muscle and tendon to check for injury.

Pectoralis major tendon injuries are graded as either type 1: tendon strain; type 2: partial tendon tear; or type 3: complete tendon tear. A health care provider will use the severity of the patient's symptoms and the grade of the tear to determine the appropriate treatment option.