Define/describe the condition
The fascia overlying the pectoralis major is continuious with the medial brachial fascia. Pectoralis major has two heads: the clavicular and sternal. The muscle inserts on the lateral aspect of the biceipital groove. The fibers from the sternal head twist 180 degrees so that the superior-most fibers at the origin insert at the inferior aspect of the bicipital groove and the the inferior-most fibers at the origin ultimately insert at the superior aspect of the groove. Thus, the pec major tendon has been described as bilaminar (howerver, it has also been decribed as trilaminar). The insertion site is 4-6 cm in length and 5mm in width. In the bilaminar description, the anterior portion of the tendon is 1 cm long and the posterior 2.5 cm long. The clavicular head and medial portion of the sternal head is innervated by the lateral pectoral nerve (C5 - C7) and the lateral portion of the sternal head by the medial pectoral nerve (C8 - T1). The nerves pierce the muscle from the medial and inferior aspects. The pectoral branch of the thoracoacromial artery provides the blood supply. The muscle adducts, internally rotates and forward flexes the humerus.
Describe the biologic basis of the disorder or the mechanism of injury
Most traumatic tears occur in weight lifters between the ages of 20 and 40 years from bench pressing (during eccentric contraction). No tears have been reported in females secondary to a sports injury.
Patient History and Physical Findings
Weakness in adduction, chest wall asymmetry, ecchymosis, pain with passive abduction.
Imaging and other Diagnostic Studies
MRI is useful in making the diagnosis. Plain X-rays and CT are of limited use with the exception of injuries with bony avulsions.
- Extent of tear
- Location of injury
- bony avulsion from proximal humerus
- rupture at bone-tendon junction
- rupture at musculotendinous jucntion
- rupture in muscle belly
- Type I: Contusion or sprain
- Type II: Partial tear
- Type III: Complete tear at:
- A: muscle origin
- B: muscle belly
- C: myotendinous junction
- D: tendon
- Poland's Syndrome - congential absence of the pectoralis major
- Biceps tendon tear
Nonoperative treatment Indications:
- Injuries in muscle belly and even the musculotendious junction are difficult to repair and are best managed conservatively.
- Partial tears
- Elderly low-demand patients
- Low demand patient in nondominant arm
Operative treatment indications:
- Complete tears
- Active, high-demand patient
- Tears at bone-tendon interface
- Repair into a bone trough lateral to the bicipital groove
- Use of suture anchors at the insertion site
- Chronic tears by require a bridging graft (e.g. achilles tendon allograft, hamstring autograft)
Pearls and Pitfalls
Acute tears (< 6 - 8 weeks old) are generally technically easier to repair and have better outcomes.
After nonoperative management:Short term immobilization followed by progressive range of motion over 6 weeks followed by gradual strengthening. Return to light weight lifting with modified techniques at 10 - 12 weeks. Return to sport when patient has full range of motion and is pain free.
Ater operative management: immobilization for 2-3 weeks; Progression to full range of motion by 6 weeks. Light resistance training beginning at 6 weeks. Full activity at 4 - 6 months if goals met (full range of motion, painless resistance exercises, strength approximating the uninjured side).
A recent prospective study (n = 20) comparing surgical to nonsurgical management reported that isokinetic testing revealed a decrease in strength of 53.8% in the nonsurgical group and 13.7% for the surgical group
Include overview of complications
DeLee, Jesse C., David Drez Jr., and Mark D. Miller, eds. DeLee & Drez's orthopaedic sports medicine principles and practice. 3rd ed. Vol. 1. Philadelphia: Saunders/Elsevier, 2010.