Torn Pectoral Muscles

Our skeleton is covered with muscles, these are the tissues responsible for allowing mobility and movement in the world around us. The pectorals are one of these muscles and the name is often shortened to “pecs”. However, muscles are not indestructible and can become torn just like any tissue. Even the hardest tissue in the body, the bones, can become broken. This article will overview the pectoral muscles and injuries they can sustain.

What is the pectoralis major muscle?

The pectoralis major muscle is a large, fan-shaped muscle that extends across the majority of the chest. It lies directly underneath the breast tissue and beneath the pectoralis major is the pectoralis minor which is a smaller, fan-shaped muscle. The pectoralis major originates in the clavicle, sternum and the cartilage of all the true ribs. From here, the fibres of the muscle travel towards the shoulder to connect to the bicipital groove of the humerus. The fibres from the clavicle travel downward and outwards. The fibres from the sternum and ribs travel upwards and outwards. The fibres between these two travel simply outwards.

This connection to the humerus in the shoulder gives clues to its function. The pectoralis major has four main functions: flexion, adduction, rotation and structural integrity. When a person moves their arm upwards from a resting position, such as throwing a ball underhand, the pectoralis major undergoes flexion to allow this to happen. When moving the arm in a downward direction, such as flapping the arms, the pecs are adducting. Upwards and downwards are not the only directions that the pecs can control but also the rotation of the arms such as when arm wrestling. The last function of the pectoralis major is to keep the arm attached to the torso of the body thus allowing structural integrity. 

While this is how the pecs function in normal physiological conditions, they can also sustain injuries. Injuries that are minor are nothing to worry about and in fact, what causes muscles to grow is very small injuries to the fibres. However, some injuries can be more drastic such as a torn pectoral muscle.  

Pectoralis major injuries

Just like any tissue, the pectoralis major is prone to injuries. These can be the result of something external that causes trauma to the muscle such as a blunt force but in relation to tearing or a rupture, the cause is likely to be due to exceeding the muscle’s capability. For example, when performing under heavy load. It should be noted that these injuries can be rare with less than 400 cases of ruptures since its first description in 1822.^1,2 This section of the article will explore the injuries that can affect the pecs.

Types of injury

There are three main types of injury that can affect the pecs. These are strains, tears and ruptures. While these names suggest that these are characteristically different injuries, they are in fact the same injury (a tear) in different stages. Strains are mild tears that causes some discomfort and will require rest to heal. Tears involve more fibres of the pectoral muscle and more function may be lost. A rupture is the most extreme tear and results in a large loss of function in the muscle.

Signs and symptoms

There are several signs that will suggest a tear to the pectoral muscle When the supposed injury took place can provide clues as to whether the pectoral muscle is involved. Most commonly the injury takes place during an exercise known as a bench press which heavily involves the pectoral muscle so if the patient was undertaking this exercise, it is likely they could have torn the muscle. There are also other signs which can indicate a tear or a rupture which includes:^1,2

• The feeling and/or sound of “pop”
• A tearing sensation
• Immediate pain
• Weakness

These immediate signs of a tear can lead onto other symptoms as the healing process begins. These symptoms can include:

• Pain and weakness in the arm
• Swelling
• Ecchymosis (Bruising)
• Loss or thinning of the axillary fold (an area around the armpit)

Diagnosis

Further from the signs and symptoms that can allow diagnosis from physical examination, diagnosis can occur from radiographs (X-rays), ultrasounds and magnetic resonance imaging (MRI). Radiographs are important when a bony abnormality is suspected with the tear. The presence of a bone would be easily identifiable. In cases where there is still a tear but no involvement of a bone, the tear might appear on a radiograph as an absence of the muscle shadow. However, the absence of a shadow is not very sensitive diagnostically, and the radiograph could still be normal even with the tear.

Diagnostic ultrasounds can be more effective and also less expensive in the diagnosis of a tear. This process would involve assessing a torn and untorn pectoral muscle in an individual. Where a difference is found in the ultrasound can indicate the presence of a tear in the pectoral muscle. This method can also pinpoint the torn muscle for further treatment. 

The use of an MRI is possibly the highest definition type of imaging to assess a tear. This is an expensive option to diagnose the tear but will provide high-quality images that can help pinpoint where the tear is in the muscle and also distinguish between a partial tear and a complete rupture. In addition, the amount of post-trauma muscle retraction can be determined. This makes it a powerful tool and it is especially applicable to young, high-performance athletes.

Causes and risk factors

As has been previously mentioned, a major cause of pectoral muscle tears is a heavy load beyond the capabilities of the muscle. The most common exercise when this can occur is the bench press exercise. This involves lying flat on a bench and pushing a weight up into the air above you. This plane of motion directly utilises the pectoral muscle to move the weight. If this weight is too great then this can cause the pectoral muscle to tear and rupture. Other sports can also cause the tear including wrestling or rugby, for example. 

Sports are not the only cause however and the injury can be work-related. Jobs that require heavy lifting can cause an injury to the pectoralis major muscle as well. Indeed the first described torn pectoralis major in 1822 was in a butcher who caused the injury while lifting beef off a hook.^1,2

Treatment

Treatment for a torn pectoral muscle can be either non-operative or operative. There are several reasons why one route of treatment may be preferred over the other. For example, non-operative treatment is generally preferred for elderly patients, suspected muscle belly ruptures and other lower-demand cases. However, regardless of which treatment option is used, initial care involves rest with a sling, cold compression and analgesics.³

Non-operative care mainly revolves around physiotherapy. Passive and active range of motion exercises will begin after 1 or 2 weeks and continue through to 6 weeks after injury. Following this, if there is an adequate range of motion and pain control, resistance exercises can be performed. In addition, heat and therapeutic ultrasound can also be used as non-operative care.³

On the other hand, operative care involves surgery and is preferred for young, active patients. The objective of the surgery is to reattach the retracted muscle and tendon into the insertion on the humerus. A variety of methods can be used to achieve this and care should be taken during the operation to not damage other parts of the body such as the nerves supplying the muscle. Once an operation has taken place, rehabilitation can commence which involves immobilising the arm for 3 to 6 weeks. This is then followed by passive and active range of motion exercises. Again this is followed by resistance exercises.³

Prevention

Prevention revolves around eliminating the causes of injury to the pectoral muscle. As the major cause is a heavy load beyond the capability of the muscle, measures should be taken to avoid excessively heavy loads. For example, if you cannot lift an object at work, employ machinery to lift it for you. For those that like to lift weights as exercise, your limits should be known and you should not push yourself too hard to limit the risk of injury.

Outlook and prognosis

Outlook and prognosis of a torn pectoral muscle depend on the route of treatment taken. For non-operative treatment, a study found that 27% of patients experience excellent results from the treatment. ⁴ The same study also found that 88% of patients who were treated surgically had excellent results. In addition, when failed non-operative patients underwent surgery, 90% had an excellent outcome. These outcomes took 6 to 24 months to be realised. 

Summary

The pectoralis major is a large muscle on your chest. Under high stress from heavy loads, the muscle can be torn resulting in injuries that range from a strain to a rupture. These injuries can be painful with a tearing sensation and weakness. It will lead to swelling and bruising in the associated area, as well as being painful for quite some time. However, the condition can be treated surgically with a high success rate.