Tear, pectoralis muscle

• Torn pectoral
• Pectoral rupture

• 840.8 Sprains and strains of other specified sites of shoulder and upper arm

• S43.499A Other sprain of unspecified shoulder joint, initial encounter
• S46.819A Strain of other muscles, fascia and tendons at shoulder and upper arm level, unspecified arm, initial encounter

• 4E: Impaired joint mobility, motor function, muscle performance, and range of motion associated with localized inflammation

Description

• Partial or complete rupture of the pectoral muscles
• Grades of tear1,2
  • Grade 1: Contusion or strain
  • Grade 2: Partial tear
  • Grade 3: Complete rupture
  • Grade 3A: Tear muscle origin
  • Grade 3B: Tear muscle belly
  • Grade 3C: Musculotendinous junction
  • Grade 3D: Muscle tendon itself
• Four common locations
  • Rupture at the humeral insertion
  • Rupture at the musculotendinous junction
  • Rupture at the muscle belly
  • Muscle torn off the sternum
• Commonly affects the pectoralis major muscle

Essentials of Diagnosis

• Rare condition
• Diagnosis is made by history and clinical exam with MRI for confirmation of location
• Occurs from a sudden high force, typically with weightlifting (i.e., bench or chest press)
• May arise from a repetitive type activity that leads to a gradual degeneration
• Sudden pain or tearing sensation in the chest may be experienced

General Considerations

• Swelling, ecchymosis, and functional pain
• Treatment may depend on location of rupture with tendon avulsion from the humerus treated with prompt surgical repair

Demographics

• More common in men between the ages of 20 and 50 that participate in cotact sports and weight lifting

Signs and Symptoms

• Audible snap or pop at the time of injury
• Sudden pain or tearing sensation in chest
• Mild swelling and ecchymosis over anterior lateral chest wall or in proximal arm
• Loss of normal pectoralis contour
• Weakness with horizontal shoulder adduction

Functional Implications

• Pushing activities
• Weight training with overload eccentric contractions: such as bench press, push ups, chin ups, dips, and chest flys can cause a rupture
• Overhead activities may be limited
• Inability to lift heavy objects

Possible Contributing Causes

• Abnormal biomechanics
• Muscle weakness or imbalance
• Muscle tightness
• Poor posture with change in humeral head position
• Excessive or inappropriate activity
• Inadequate warm up
• Steroid use
• Forceful eccentric activity (i.e., bench pressing)
• Often seen in football and rugby injuries

Differential Diagnosis

• Long head of biceps tendon rupture
• Shoulder dislocation
• Proximal humerus fracture
• Rotator cuff tendon tear
• Medial Pectoral nerve entrapment

Imaging

• Radiographs
• MRI
• Diagnostic ultrasound

• Radiographs may show avulsion from humerus
• MRI can be useful in assessing location and severity of tear
• Acute tears will demonstrate hemorrhage and edema and chronic tears will demonstrate fibrosis and scarring

Medication