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Biceps pathologies

Contents

Biceps lesion

Definition

  • An inflammatory tenosynovitis, most commonly affecting the tendinous portion of the long head of the biceps as it travels within the bicipital groove of in the proximal humerus1
  • The continuum of clinical pathology ranges from acute inflammatory tendinitis to degenerative tendinopathy
  • Both the biceps and brachialis are the strongest flexors of the elbow, so a positive resistance tests implicates these two in particular (although many other muscles perform the same function but in a weaker sense)
    • Pain in shoulder indicates the biceps and not the brachialis
    • Resisted supination with elbow flexed is added to the consideration, if positive this also indicates the biceps is at fault

Causes

  • Sports with overhead arm throwing functions such as 2
    • Baseball
    • Softball
    • Volleyball
    • Gymnastics
    • Swimming
  • Occupational work with manual labor
  • Can be seen in association with subscapularis injuries and tears
  • Injury to shoulder and or neck is important, and any relevant surgical history

Localization

  • Long head of biceps - intra-articular
    • If at this location, this will impinge the tendon during arm elevation giving a painful arc
  • Long head of the biceps – sulcus/bicipital groove

Development

  • Biceps tendinopathy begins with the early stages of tenosynovitis and inflammation secondary to 3
    • Repetetive traction
    • Friction
    • Shoulder rotation
  • Inflammation develops early in the tendinous portion in the bicipital groove
  • The tendon expands in diameter secondary to swelling and/or associated hemorrhage, further compromising the tendon as it becomes mechanically irritated in its confined space
  • Preexisting rotator cuff pathology can directly compromise the biceps long head itself as it is a direct extension of the synovial lining of the glenohumeral joint
  • As the injury develops, structures are affected in the following ways
    • Sheath thickening
    • Fibrosis
    • Vascular compromise
  • The tendon undergoes degenerative changes, and associated scarring, fibrosis and adhesions eventually compromise the tendons mobility
  • As a result, the tendon becomes “locked” in the groove, further exacerbating the potential points of traction and overall increases shear forces experienced by the tendon along its course
  • In the end, the biceps long head tendon can eventually rupture at its origin near the superior glenoid tubercle, or as it exits the bicipital groove near its musculotendinous junction

Indications

  • Gradual onset of anterior shoulder pain experienced usually at the mid-arm
    • The pain is usually at the anterior aspect of the shoulder 4 5 6
  • Overhead activities provoke symptoms
  • Pain radiating from shoulder down the anterior arm
  • Pain at rest
  • Pain at night
  • Snapping tendon
    • During certain shoulder movements a palpable snap is present, typically in throwing athletes

Examination

  • Resisted flexion of elbow – painful
  • Resisted flexion of the shoulder with the elbow slightly flexed and forearm supinated is painful (Speed test)
  • Supination of elbow – painful
  • Resisted adduction – painful
    • Becomes painless if performed with elbow flexed due to less stretch on muscle and tendon
    • Only painful if intra-articular lesion
  • Painful arc
    • Indicates the lesion is at the intra-articular part of the tendon becoming impinged under the acromion
    • Only present in intra-articular lesion
  • Palpation
    • Only possible if the lesion is in the sulcus
      • In this case the palpation over the bicipital groove is painful

Additional functions

  • The long head of the biceps has a role in the dynamic stability of the shoulder joint by stabilizing the shoulder, other studies have also refuted the theory so it remains controversial 7 8
  • More recent studies show that the biceps brachii long head is thought to enhance dynamic stability of the shoulder but only within the first 30° of elevation of the arm9

Considerations

  • Pressure and strain on the glenoid part of the biceps is strongest in an abducted and overhead position
  • The tendon of the long head of the biceps has a passive stabilizing role in the shoulder, its role is considered controversial in its ability to maintain dynamic stability of the shoulder

Biceps rupture

Localization

  • Usually at the proximal part of the long head of the biceps
  • Distal ruptures happen but are rare, may be seen in younger athletes often a result of local direct trauma

Causes

  • Degeneration over time as a result of wear and tear

Indications

  • Male patients over the age of 50 are more common of those suffering from this ailment
    • Other studies show that injury usually happen between the age of 35-54
    • Crack or tear may be heard at the moment of the tear
    • Some temporary pain is felt in the upper arm
    • A clear prominence may be seen especially if the patient is actively trying to flex the biceps

Examination

  • No weakness is usually felt
    • Due to brachialis compensating for the weakness of the biceps
    • The biceps is considered a strong forearm supinator but a weak elbow flexor 10
    • There is a very prominent and palpable sign of retraction of the biceps muscle belly (popeye deformity) 11

References

  1. https://www.ncbi.nlm.nih.gov/books/NBK533002/
  2. https://www.ncbi.nlm.nih.gov/books/NBK533002/
  3. https://www.ncbi.nlm.nih.gov/books/NBK533002/
  4. https://pubmed.ncbi.nlm.nih.gov/30422594/
  5. https://pubmed.ncbi.nlm.nih.gov/30137823/
  6. https://pubmed.ncbi.nlm.nih.gov/30475566/
  7. https://www.ncbi.nlm.nih.gov/books/NBK519538/
  8. https://www.ncbi.nlm.nih.gov/books/NBK533002/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5505302/
  10. https://www.ncbi.nlm.nih.gov/books/NBK519538/
  11. https://www.ncbi.nlm.nih.gov/books/NBK513235/