Variations in the extensor grooves on the radial styloid process in Chinese population.

PURPOSE: The aim was to provide anatomical data for local blocking treatment of de Quervain's disease through investigating features and classification of the first extensor groove on the radial styloid process.

METHODS

Two hundred and eighty-four specimens of the intact distal extremity of dry radii from Chinese corpses were investigated and measured systematically in this study. Morphological features of the extensor grooves on the radial styloid process were observed by visual inspection. Correlation parameters of variability were measured with a vernier caliper.

RESULTS

The study showed that the most prevalent group was Type I (the extensor groove that was deep and divided into two sub-grooves by a tiny bony ridge) accounting for 63.73 % (181 specimens). Seventy-nine specimens belonged to Type II (the extensor groove without the tiny bony ridge) accounting for 27.82 % and 24 specimens belonged to Type III (almost without any extensor groove on the radius) accounting for 8.45 %. The distance between the processus of the palmar bony ridge and the processus of the dorsal bony ridge (defined as AC) was 11.55 ± 1.32 mm. The distance between the processus of the palmar bony ridge and the sharp point of the styloid process of the radius (defined as AB) was 17.09 ± 1.99 mm.

CONCLUSIONS

The extensor groove could provide a subjective safe operation range for the steroid injections, which could be defined depending on the bony landmarks, which are easy to identify in the body surface. This anatomical variation is important in the management of de Quervain's disease.