Pectoralis Major Rupture

Topic updated on 06/11/14 10:14am
  • Epidemiology
    • demographics
    • location
      • most commonly occurs as a tendinous avulsion
  • Pathophysiology
    • mechanism
      • excessive tension on a maximally eccentrically contracted muscle 
      • may be an iatrogenic injury caused during open rotator cuff repair
  • Pectoralis major topic
    • innervation
      • by lateral and medial pectoral nerves  
    • two heads
      • clavicular head
      • sternocostal head
    • one of four muscles connecting the upper limb to the thoracic wall 
      • other muscles include 
        • pectoralis minor
        • subclavius
        • serratus anterior
  • Biomechanics
    • inferior fibers of sternal head at maximal stretch during final 30 degrees of humeral extension
      • position at which pectoralis major is most vulnerable to rupture (as with bench pressing)
  • History
    • patient may report a sharp tearing sensation with resisted adduction and internal rotation
  • Symptoms
    • pain and weakness of shoulder
  • Physical exam
    • swelling and ecchymosis
      • if localized to the anterior arm, then humeral attachment rupture is more likely than a musculotendinous junction rupture 
    • palpable defect and deformity of the anterior axillary fold
    • weakness with adduction and internal rotation
  • Radiographs
    • recommended views
      • standard shoulder trauma series (true AP, scapular Y, and axillary lateral)
    • findings
      • often normal
  • MRI 
    • useful in identifying the site and extent of the rupture
      • may show avulsion of the pectoralis major tendon from the humerus  
  • Nonoperative
    • initial sling immobilization, rest, ice, NSAIDs
      • indications
        • may be indicated for partial ruptures
        • tears in the muscle or musculotendinous junction
        • low-demand patients
  • Operative 
    • open exploration and repair of tendon avulsion
      • indications
        • tendon avulsion from the bone (will see ecchymosis down arm) 
        • treatment of choice for high level athletes
      • outcomes
        • may show improvement regardless of location of tear


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Qbank (3 Questions)

(SBQ05.11) A 24-year-old bodybuilder reports shoulder pain after an injury while bench pressing. Physical exam reveals ecchymosis and swelling in his right upper arm as shown in Figure A. He has weakness in internal rotation but has good strength in external rotation and abduction; his apprehension test is negative. When he puts his hands on his hips, his upper chest is asymmetrical. When is surgery indicated for this injury? Topic Review Topic
FIGURES: A          

1. Surgery is not indicated; conservative management including ice, rest and NSAIDs are recommended
2. After a period of immobilization, followed by physical therapy, has failed
3. When the pectoralis major has avulsed from its humeral insertion
4. When asymmetry of the upper chest wall is noted
5. If swelling and ecchymosis are primarily located on the chest wall rather than the upper arm

(OBQ07.49) A weightlifter feels a pop in his anterior left shoulder while doing a bench press exercise. Which nerve innervates the muscle that is disrupted as seen on the MRI shown in Figure A? Topic Review Topic
FIGURES: A          

1. Axillary
2. Musculocutaneous
3. Upper and lower subscapularis
4. Suprascapular nerve
5. Lateral and medial pectoral nerves

(OBQ07.249) During a bench press, when is the pectoralis major insertion at greatest risk of rupture? Topic Review Topic

1. Initiation of upward motion
2. Point of maximum elevation
3. During downward deceleration
4. When bar is touching chest
5. No difference in rupture rate is seen



This video demonstrates the surgical repair of an acute pectoralis major tendon...
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