Quantification of the distal radial artery for improved vascular access

There is no consensus in the literature as to which point of the radial artery (RA) is the safest to attempt vascular access. The purpose of this study was to measure the diameter, tortuosity and branching patterns of the distal RA.

140 cadaveric RAs (66 male, 74 female) were dissected and measured. The external diameter of the RA was measured at 2 cm increments starting at the radial styloid process (SP), moving proximally. The location and degree of 2-dimensional arterial tortuosity were recorded if > 35 degrees. Branches of the RA were recorded with respect to their distance from the SP.

We observed that the right RA significantly increased in diameter at distances beyond 4 cm proximal from the radial SP, regardless of the sex of the individual. This increase in size was not noted on the left RA's. Muscular artery branches of the distal RA were noted on average 1.82 cm proximal from the SP. Clinically significant tortuosity was present on average 3.47 cm proximal from the radial SP. The left RA did not significantly change in size along its course, but its statistically similar diameter when compared to the right RA allows us to make a recommendation this is applicable bilaterally.

Our data suggests that regardless of gender, vascular access of the RA could be safely performed at distances greater than 4 cm from the SP to yield a vessel with a larger diameter, less tortuosity, and fewer branches.