Median nerve in the distal forearm: A Cadaveric Morphometric Study

Area of Science:

• Anatomy
• Surgical Anatomy
• Peripheral Nerve Anatomy

Background:

• The median nerve (MN) is crucial for distal forearm function, but its precise location can vary.
• Superficial anatomical landmarks for the MN may lack individual reliability.
• Accurate morphometric data are essential for safe interventional procedures in the distal forearm.

Purpose of the Study:

• To precisely identify the morphometric features of the median nerve in the distal forearm.
• To evaluate the positional relationships of the median nerve with fixed bony landmarks and adjacent structures.
• To assess the reliability of bony landmarks compared to superficial tendon references for median nerve localization.

Main Methods:

• Dissection of 31 formalin-fixed cadaver forearms.
• Measurement of median nerve length, width, and surface area.
• Quantification of distances from the median nerve to the ulnar styloid process, radial styloid process, and flexor carpi radialis tendon.
• Evaluation of median nerve-ulnar nerve distance.
• Analysis of differences based on gender and side.
• Correlation analysis between wrist width and nerve morphometrics.

Main Results:

• No statistically significant differences in morphometric parameters were found between genders or sides.
• Mean distance from the median nerve to the radial styloid process: 20.97 mm.
• Mean distance from the median nerve to the ulnar styloid process: 19.44 mm.
• Mean distance from the median nerve to the flexor carpi radialis tendon: 3.83 mm.
• Mean median nerve surface area: 1.49 cm².
• Median nerve-ulnar nerve distance was consistently narrow (mean 12.09 mm).
• Positive correlation observed between wrist width and median nerve length/surface area.

Conclusions:

• Morphometric features of the median nerve in the distal forearm align consistently with bony landmarks.
• Bone landmarks offer greater reliability for median nerve localization than variable superficial tendon references.
• These data contribute to improving the safety of interventional procedures in the distal forearm and hand.
• Findings from cadaveric specimens require validation in living subjects for direct clinical applicability.