Flexor Pulley System

Topic updated on 02/09/15 12:59am
Flexor Pulley System-Fingers
  • Annular ligaments
    • A2 and A4 are critical to prevent bowstringing
      • most biomechanically important  
    • A1, A3, and A5 overlie the MP, PIP and DIP joints respectively 
      • originate from palmar plate  
    • A1 pulley most commonly involved in trigger finger
  • Cruciate pulleys
    • function to prevent sheath collapse and expansion during digital motion
    • 3 total at the level of the joints
Flexor Pulley System-Thumb

  • Oblique pulley
    • originates at proximal half of proximal phalanx
    • most important pulley in thumb 
    • facilitates full excursion of flexor pollicis longus
    • prevents bowstringing of flexor pollicis longus 
  • Annular pulleys
    • A1 pulley
      • at the level of the volar plate at the MCP joint
      • ~6mm in length
    • A2 pulley
      • contributes least to arc of motion of thumb


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Qbank (2 Questions)

(OBQ08.274) Which of the following flexor tendon annular pulleys originate from palmar plates overlying joints? Topic Review Topic

1. A1, A3, A5
2. A2, A4
3. A1, A2, A4
4. A1, A2, A3
5. A2, A4, A5

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