Abstract
Purpose The terminal branches of the posterior interosseous nerve (PIN) are the main articular
branch on the dorsal aspect of the wrist. Its relationship to dorsal wrist arthroscopic
portals has not yet been elucidated. The purpose of this study was to quantitatively
describe the anatomical relationships between the dorsal wrist arthroscopic portals
and the PIN.
Methods Dorsal wrist arthroscopic portals were established in 28 cadaver extremities, after
which the limbs were dissected. Measurements were taken from the portals to the PIN.
Results The PIN passed ulnar to the 3/4 portal with a mean distance of 4.8 mm (range: 1.2–12.0,
standard deviation [SD] = 2.6). The PIN passed radial to the 4/5 portal with a mean
interval of 9.0 mm (range: 3.8–12.7, SD = 2.3). The main trunk of PIN or its closest
terminal branch was a mean of 7.2 mm (range: 0.0–13.2 mm, SD = 3.1) radial to the
midcarpal radial (MCR) portal. In 2 of the 28 specimens, one terminal branch of PIN
lay directly over this portal. The distance between the midcarpal ulnar (MCU) portal
and the PIN or its closest terminal branch was only a mean of 1.6 mm (range: 0–6.4 mm,
SD = 2.0). In 15 of the 28 specimens, the PIN lay directly over the MCU portal, or
the portal was located between the terminal branches of PIN.
Conclusion The MCU portal was the most precarious, due to the close proximity of PIN and its
terminal branches. The 3/4 and MCR portals were also at risk, while the 4/5 portal
was relatively safe for the PIN.
Keywords
arthroscopy - wrist joint - posterior interosseous nerve - anatomy