Anatomical study of the distal end of cadaveric human ulnae: a clinical consideration for the management of distal radioulnar joint injuries

Sharma A, Kumar A, Singh P
Correspondence: Dr Anu Sharma, anuashwani2003@yahoo.com

ABSTRACT
Introduction Detailed anatomical knowledge of the distal end of the ulna plays a pivotal role in understanding post-injury instability and painful conditions at the distal radioulnar joint (DRUJ), which can be due to avulsion of the ulnar styloid process or ulnar styloid triquetral impaction syndrome. With this in mind, data on the morphological features of distal ulnae in the Indian population was collected.
Methods The distal end of 100 human ulnae (50 right-sided and 50-left sided) of unknown gender from the anatomy department’s bone bank were studied with regard to the seat (articular circumference of the head of ulna), ulnar styloid process, fovea and pole (articular surface for articulation of triangular fibrocartilaginous complex of the wrist on the head of ulna).
Results The average length of the styloid process was 5.2 mm in the right-sided ulnae and 5 mm in the left. The mean maximum height of the seat was noted to be 5.9 mm and 6.9 mm on the right-and left-sided ulnae, respectively. The maximum width of the pole was calculated to be 5.4 mm (right-sided ulnae) and 6.1 mm (left-sided ulnae). The shapes of the pole and styloid process were also noted. Extensor carpi ulnaris groove was more commonly found on the left-sided ulnae.
Conclusion The study provides an anatomical database of the morphometry of parts of the distal end of the ulna in the Indian context, which will aid in the early management of DRUJ injuries.

Keywords: distal end of ulna, distal radioulnar joint, head of ulna, styloid process of ulna
Singapore Med J 2011; 52(9): 673–676