Sports Medicine: Just the Facts

press emphasize pectoralis contraction. As the shoul-

ders extend posterior to the chest wall, significant

eccentric stresses are placed on the muscle tendon

junction and the tendon insertion. Anabolic steroids

may place this structure at additional risk of injury.

PECTORALIS MAJOR ANATOMY

• The pectoralis major comprises two muscular por-
  tions originating on the clavicle and sternocostal (ribs
  1 through 5). There are additional inferior attachments
  along the external oblique fascia. The tendon has a
  trilaminar insertion along the humerus, lateral to the
  biceps groove (McEntire, Hess, and Coleman, 1972).


• Muscular portions have independent neural innerva-
  tion from branches of the lateral pectoral nerve (C5,
  C6, C7) and medial pectoral nerve (C8, T1). Vascular
  supply is from the pectoral major branch of the cora-
  coacromial artery.


• There are independent tendon insertions along the
  proximal humerus. The clavicular head is more super-
  ficial, and the sternal costal head is deep and more
  superior. There are muscular attachments more dis-
  tally extending the insertion.


• There is intimate contact along the anterior edge of
  the deltoid. Pectoralis injuries may appear as deltoid
  injuries if detachment or atrophy is detected. The
  cephalic vein travels along the superficial portion of
  this interval.

PECTORALIS TEARS

• The most common mechanism of injury is forced
  adduction against resistance. Direct injury can create
  tears at the muscle and muscle tendon junction.
  Indirect injuries via muscular eccentric contraction
  including bench press, breaking a fall, and wrestling
  are more commonly humeral avulsion injuries (Noble
  and Bell, 1996).
  •Tears can be classified as sprain, partial tear (most
  common), or complete tear. Location of tear can be
  humerus avulsion, muscle tendon junction, tendinous
  ruptures, and muscular tears.


• Clinical presentation of a tear is hematoma, weakness
  of shoulder adduction and internal rotation, deformity
  of the anterior axillary fold, prominent deltoid, asym-
  metric pectoralis muscular bulge, and arm swelling.


• Provocative testing can be performed on seated
  patients with their hands on their hips. Asking them to
  apply an adduction force recreates pain and visual
  asymmetry of the pectoralis compared to the unin-
  jured extremity.
  
  
  • On a supine patient with the arm abducted, palpation
    along the humerus insertion and the muscular tendon
    junction may be helpful in identifying the location of
    the tear. Slight forward flexion and neutral rotation
    allows for deeper examination.
  
  
  • Magnetic resonance imaging can identify tear and
    hematoma. Location of the tear is important to
    prognosis and treatment options. Tears within the
    muscle or at the muscle tendon junction have
    poorer surgical outcomes than tendon avulsion
    injuries.
  
  
  
  

PECTORALIS TEARS TREATMENT

• Early surgical repair is recommended for patients who
  participate in athletics and strenuous activities
  (Zeman, Rosenfeld, and Lipscomb, 1979). Reduction
  in adduction strength can be 50% or greater if treated
  nonoperatively (Wolfe, Wickiewicz, and Cavanaugh,
  1992).


• Complete tears and avulsions should be repaired early
  with anticipated satisfactory results. Delayed repairs
  2–3 months may require a graft due to adhesions and
  muscular atrophy.
  •Surgical repair of tendon avulsions are best achieved
  with suture anchors or bone tunnels. Anchors should
  be located along the lateral aspect of the biceps
  groove. Superior reinforcement can be added includ-
  ing deltoid pectoralis interval closure.


• Muscular repairs have increased risk of failure (Noble
  and Bell, 1996). Tissue augmentation as in xenograft
  or allografts may increase successful repairs when
  compromised tissue is detected at surgery.


• Postoperative management includes a sling for 4 to
  6 weeks. Early pendulum exercises with restricted
  flexion to the face, external rotation to 30°, and
  avoidance of extension for 6 weeks. Strengthening
  can begin at 10–12 weeks. Restrictions for maximal
  resistance are commonly greater than 4 months.


• Conservative treatment to partial and muscular tears
  includes stretching at 2 weeks, terminal stretching at
  4–6 weeks, and strengthening at 12 weeks. Muscular
  compensation can occur with subscapularis, deltoid,
  latissimus dorsi, and teres major.

REFERENCES

Abrams JS: Special shoulder problems in the throwing athlete:

Pathology, diagnosis and nongenerative management. Clinic

Sports Med 10(4):839–861, 1991.

286 SECTION 4 • MUSCULOSKELETAL PROBLEMS IN THE ATHLETE