Median nerve in the distal forearm: A Cadaveric Morphometric Study

The median nerve (MN) is a main peripheral nerve that includes superficial motor and sensory fibers in the distal forearm. The proximity of the MN to the forearm muscle tendons and neurovascular structures enhances its clinical significance. The safety of invasive procedures in this area relies on a thorough understanding of the nerve morphometric characteristics. However, commonly used superficial anatomical landmarks may not provide the same reliability for every individual. This study aimed to precisely identify the morphometric features of the MN in the distal forearm by using fixed bony landmarks and to evaluate its positional relationships with nearby anatomical structures. Measurements of the length, width, surface area, and distances from the MN to the ulnar styloid process, radial styloid process, flexor carpi radialis tendon, and ulnar nerve were measured by dissecting the forearms of 31 formalin-fixed cadavers. Differences in gender and side were evaluated, along with the connections between wrist width and various morphometric parameters. There was no statistically significant difference between genders or sides. Without regard to sex or side, the mean distance from the MN to the radial styloid process was 20.97 ± 3.02 mm, to the ulnar styloid process was 19.44 ± 4.83 mm, and to the flexor carpi radialis tendon was 3.83 ± 0.96 mm. The mean surface area of the nerve was 1.49 ± 0.63 cm2. Median nerve-ulnar nerve distance was 12.09 ± 3.77 mm, and it remained within a narrow range. Furthermore, a positive correlation was observed between wrist width and both nerve length and surface area. The morphometric features of the MN in the distal forearm consistently align with bone landmarks, making these structures a more reliable guide than variable superficial tendon references. These data will contribute scientific knowledge to improve the safety of interventional methods, particularly in distal forearm and hand surgery. However, as these findings are based on cadaveric specimens, their direct clinical applicability should be interpreted with caution and warrants further validation in living subjects.