# Risk of anterior interosseous nerve injury during forearm surgery: a cadaveric study

## TL;DR

This study identifies the area in the forearm where the anterior interosseous nerve is most at risk during surgery, helping surgeons avoid nerve damage.

## Contribution

The study provides new anatomical insights into the anterior interosseous nerve's vulnerability during forearm surgery.

## Key findings

- The AIN originates on average 13 mm from the radius and starts contacting the bone 8 mm away.
- The highest risk for AIN injury is at the junction of the proximal and middle thirds of the forearm.
- Excessive traction or deep retractor placement in this region should be avoided to prevent nerve injury.

## Abstract

The anterior interosseous nerve (AIN) is susceptible to injury during forearm surgery, particularly open reduction and internal fixation (ORIF) of radius fractures. This study aimed to analyze the anatomical relationships between the AIN and the radius to identify regions most vulnerable to iatrogenic injury.

A cadaveric study was conducted on ten fresh, non-embalmed forearms. Standardized dissections were performed to assess the course of the AIN, its motor branches, and their proximity to bony landmarks. Measurements were taken using a graduated ruler, with reference to the radius, the bi-epicondylar and bi-styloid lines.

The AIN originated, on average, 13 mm from the radius, initially separated from the bone by the flexor digitorum profundus and flexor pollicis longus. The first branch to the flexor pollicis longus emerged at an average of 8 mm from the radius, marking the start of the nerve’s close contact with the bone. The highest risk zone for AIN injury was identified at the junction of the proximal and middle thirds of the forearm.

The AIN and its motor branches exhibit significant anatomical variability but consistently demonstrate proximity to the radius at the proximal-middle third junction. To minimize iatrogenic injury, care should be taken when exposing the anterior radius, particularly by avoiding excessive traction or deep retractor placement in this region.