The Relationship Between the Intercrease Line and the A1 Digital Pulley: A Cadaveric Study

Abstract

Background: Accurate identification of surface anatomy is critical to identify the location of the A1 pulley. The intercrease line (ICL) describes a transverse line between the radial edge of the proximal palmar crease and the ulnar edge of the distal palmar crease. We hypothesize that this easily identifiable surface landmark approximates the location of the A1 pulley. Methods: The ICL was marked on 7 cadaver hands. We marked a point proximal to the proximal digital crease (PDC) equal to the distance between each digit's proximal interphalangeal crease (PIC) and PDC (the PIC/PDC point). We calculated the distance between PIC/PDC points and proximal edge of the A1 pulleys. Results: The ICL was proximal to A1 in all digits. The PIC/PDC point was distal to A1 in the ring finger, and proximal to A1 in the index, middle, and small fingers. The PIC/ PDC point was closer to the A1 pulley than the ICL in the middle and ring fingers. Conclusions: Despite less accuracy than the PIC/PDC point at approximating the location of the A1 pulley, the ICL is reliably proximal to the A1 pulley.

Morphological features of the chiasma tendinum and its relation with surface landmarks and pulleys: a cadaveric study

“…Fiorini et al measured A1 pulley (proximal edge) to metacarpophalangeal crease distance, A1 pulley length and metacarpophalangeal crease to proximal interphalangeal crease distance for 2nd to 5th fingers, and their findings are in accordance with ours [5]. The findings of Watkins et al for A1 pulley (proximal edge) to interpalmar crease distance are also similar to ours, except for the 3rd finger-which may be due to an uncertainty in the definition of interpalmar crease, which particularly concerns the level of 3rd finger [22].…”

“…Relation of superficial landmarks (creases) with finger tip FT-DPC: fingertip-distal interphalangeal crease distance; FT-PPC: fingertip-proximal interphalangeal crease (in cases with one wide or double crease, the middle point was used); FT-PDC: fingertip-palmar digital crease distance (in cases with one wide or double palmar digital creases, only proximal border was used); FT-IPC: fingertip-interpalmar line distance (interpalmar line was defined as the line joining the ulnar origin of the distal palmar crease and the radial origin of the proximal palmar crease. [22]). FT-WC: fingertip-wrist crease distance.…”

“…FT-IPC: fingertip–interpalmar line distance (interpalmar line was defined as the line joining the ulnar origin of the distal palmar crease and the radial origin of the proximal palmar crease. [ 22 ]).…”