Third cruciate pulley

Ligamentum cruciformis tertium

Definition

The three cruciform pulleys (C1–C3) are formed by crisscrossing fibers of the components of the annular pulley. The cruciform pulleys are designed to permit deformation of the tendon sheath during flexion without impingement of the tendon itself . The cruciform pulleys are the most variable in shape and prevalence and more difficult to depict on MRI:

  • The first cruciate pulley (C1) is located between A2 and A3 pulleys immediately proximal to the PIP joint and attach to the volar aspect of the proximal phalanx.

  • The second cruciate pulley (C2) is located between A3 and A4 pulleys immediately distal to the PIP joint.

  • The third cruciate pulley (C3) is located between A4 and A5 pulleys immediately proximal to the DIP joint.

References

Petchprapa CN, Vaswani D. MRI of the Fingers: An Update. AJR Am J Roentgenol. 2019 Sep;213(3):534-548. doi: 10.2214/AJR.19.21217. Epub 2019 Jul 3. PMID: 31268729.

Gupta P, Lenchik L, Wuertzer SD, Pacholke DA. High-resolution 3-T MRI of the fingers: review of anatomy and common tendon and ligament injuries. AJR Am J Roentgenol. 2015 Mar;204(3):W314-23. doi: 10.2214/AJR.14.12776. PMID: 25714317.

Clavero JA, Alomar X, Monill JM, Esplugas M, Golanó P, Mendoza M, Salvador A. MR imaging of ligament and tendon injuries of the fingers. Radiographics. 2002 Mar-Apr;22(2):237-56. doi: 10.1148/radiographics.22.2.g02mr11237. PMID: 11896215.