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.