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What Are Biceps, Triceps and Pectoralis Injuries? 

The biceps and triceps are muscles in the upper arm, while the pectoralis (pectoral, pec) is a muscle that starts in the chest and collarbone and attaches onto the humerus (upper arm bone). The pectoralis and triceps are responsible for pushing motions–that is, extending the arms–while the biceps partially governs pulling motions–flexing the arms—as well as turning the palm up. 

Common injuries to these muscles include: 

  • Tendinitis—inflammation or irritation of the tendon, which connects the muscle to bone 

  • Rupture–when the tendon has become completely disconnected from the bone 

  • Strain–an injury to the muscle itself or the junction of the tendon and the muscle  


Symptoms will depend on the nature and location of the injury, but in general they are: 

  • Pain 

  • Reduced range of motion 

  • Swelling, bruising or tenderness 

  • Visual deformity 

  • Weakness 

Injuries to the triceps will be felt in the back of the arm—often just above the elbow—and will make extending the arm difficult. The pain from biceps injuries will be on top of the arm and extends into the forearm. Often, flexing the elbow or turning the palm up, especially in a repetitive fashion, will lead to pain and a sensation of weakness. Pectoral injuries will often lead to pain, bruising and deformity in the chest area near the armpit. 


Causes will vary depending on the type of injury and where it happens. Overuse is a common cause of injuries of the biceps and triceps, and any of the injuries can be caused by a traumatic event. Certain types of athletes are particularly prone to biceps, triceps or pectoral injuries. The bench press exercise is the most common cause of pectoral tears. Older people usually have more wear and tear on their tendons, so they may be more at risk for tendinitis and tendon tears. Biceps and triceps injuries are more common in men over 40. 


A medical history and physical exam are usually the first steps in diagnosing a biceps, triceps or pectoral injury. Because X-rays show only dense tissue like bones, injuries to these muscles or tendons usually will not show up on an X-ray. A magnetic resonance imaging (MRI) scan or computed tomography (CT) scan are more likely to detect tendinitis, tendon tears or muscle strains. 


Tendinitis and muscle strains can usually be treated with conservative methods, including rest, ice, splinting and anti-inflammatory medicines or painkillers. 

A tendon tear may require surgical repair. The surgeon will reattach the tendon to the bone using sutures, often in combination with anchor or small plate implants


If you’re seeking care for a biceps, triceps or pectoral injury, follow the link below and answer a few short questions. Someone will get back to you as soon as possible. Thank you for choosing Summit Health. 

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