The objective of this study was to determine the precise departure points of the articular branches innervating the distal radio-ulnar joint from the anterior and posterior interosseous nerves. The study sample consisted of 116 upper limbs from adult human cadavers. The articular branches were prepared under the dissection microscope to take measurements using the radial styloid process as point of reference. The articular branch departed from the anterior interosseous nerve at a mean distance of 2.9 cm proximal to the styloid for a radius length of 20.5 cm, and 3.7 cm for a radius length of 26.5 cm, respectively. For the posterior interosseous nerve, the departure point was at a mean distance of 3.1 cm (radius length of 20.5 cm) and at 4.0 cm (radius length of 26.5 cm). Apart from a single branch from the posterior interosseous nerve, all articular branches were located distal to the proximal border of the pronator quadratus. Results indicate that wrist denervation from the volar approach, if performed at the proximal border of the pronator quadratus, or from the dorsal approach at a distance of 4.8 cm (for a radius length of 20.5 cm) or 6.2 cm (for a radius length of 26.5 cm) proximal to the radial styloid process, will eliminate the nerve supply to the distal radio-ulnar joint in the majority of cases.
Keywords: Anterior interosseous nerve; distal radio-ulnar joint; innervation; posterior interosseous nerve; wrist denervation.