What is the order of the pulleys in the anatomy of trigger finger (TF)?

Updated: Apr 26, 2021
  • Author: Satishchandra Kale, MD, MBBS, MBA, MCh(Orth), FRCS(Edin), FRCS(Tr&Orth); Chief Editor: Harris Gellman, MD  more...
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Answer

The order of the pulleys from proximal to distal is as follows:

  • The A1 pulley overlies the metacarpophalangeal (MCP) joints; it is released during surgery for TF (see the image below)
  • The A2 pulley overlies the proximal end of the proximal phalanx
  • The C1 pulley overlies the middle of the proximal phalanx
  • The A3 pulley lies over the proximal interphalangeal (PIP) joint
  • The C2 pulley lies over the proximal end of the middle phalanx
  • The A4 pulley lies over the middle of the middle phalanx
  • The C3 pulley lies over the distal end of the middle phalanx
  • The A5 pulley lies over the proximal end of the distal phalanx
Flexor tendons pass within tendon sheath and benea Flexor tendons pass within tendon sheath and beneath A1 pulley at approximately metacarpal head, beyond which they travel into digit.

The A2 and A4 pulleys are vital in preventing bowstringing of the flexor tendons and must be preserved or reconstructed after any damage to them.


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