Ultrasonographic Findings of Superficial Radial Nerve and Cephalic Vein

Objective: To investigate the anatomic relationship between the superficial radial nerve (SRN) and the cephalic vein (CV) through ultrasonography due to the possibility of SRN injury during cephalic venipuncture.

Methods: Both forearms of 51 healthy volunteers with no history of trauma or surgery were examined in proximal to distal direction using ultrasonography. We measured the distance between the radial styloid process (RSP) and the point where the SRN begins contact with the CV, and measured the distance between the RSP and the point where the SRN is separated from the CV. The point where the SRN penetrates the brachioradialis fascia was also evaluated.

Results: The SRN came in contact with the CV at a mean of 9.35±1.05 cm from the RSP and separated from the CV at a mean of 6.29±1.17 cm from the RSP. The SRN pierced the brachioradialis fascia at a mean of 10.31±0.89 cm from the RSP and horizontally 1.35±0.36 cm medial to the radius margin. All parameters had no significant differences in gender or direction.

Conclusion: The SRN had close approximation to the CV in the distal second quarter of the forearm. We recommend for cephalic venipuncture to be avoided in this area, and, if needed, it should be carried out with care not to cause injury to the SRN.