Strength of human pulleys.

The length, breaking stength, and tensile strength of each of the annular fibroosseous pulleys of digital flexor sheath in ten fresh human cadaver specimens were measured. The first annular pulley and the fourth annular pulley were found to be the strongest, while the second annular pulley was the weakest. The design of artificial pulleys should reproduce the strength of the first annular and fourth annular pulleys. Suggested minimum requirements for the breaking strength of artificial implant pulleys may be made based on these studies.