The Incidence and Shape of the Digital Pulleys: a Study of 192 Fingers in 48 Cadaveric Hands

We dissected 192 fingers in 48 fresh cadaveric hands (23 right and 25 left hands from 26 female and 22 male donors) and analysed the incidence, location, length and structure of the five annular and three cruciform pulleys. No statistically significant differences were found between left and right or between male and female hands. The A1, A2 and A4 pulleys were present in all fingers, while the incidence of other pulleys varied. We found 32 different patterns of pulley combinations. The structure of the pulleys also varied. Most important was the variation of A1, which consisted of one to four separate rings. In 18% there was no gap between the A1 and A2 pulleys. A greater understanding of the anatomical variation of the pulley system is beneficial for hand surgeons performing open or percutaneous trigger finger releases and for radiologists examining the area sonographically.