Deep and shallow forms of the sulcus for extensor carpi ulnaris
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Updated: Nov 8, 2026

Vascularized Composite Hand Allograft Procurement and Preparation for Distal and Proximal Forearm Allotransplantation: A Stepwise Approach
Published on: May 23, 2025
T Nakashima1, T Hojo, H Furukawa
1Department of Anatomy and Anthropology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Abstract:
Anatomical variations in the sulcus for the tendon of extensor carpi ulnaris were studied in 240 upper limbs. The sulcus lies between the head and the styloid process on the dorsal surface of the distal end of the ulna. This groove has deep and shallow forms and, rarely, a flat form. The sulcus was classified into 4 grades according to its depth. Grade I, a deep sulcus, was found in 51.3%. Grades II and III are shallow, but the styloid process in grade II is more prominent than in grade III. The former was found in 28.8%, the latter in 14.2%. Grade IV is a flat form. This was rare and found only in 1.3%. This variation was not age-related, but was a congenital feature.
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