The proximal ulna: An anatomic study with relevance to olecranon osteotomy and fracture fixation.

The purpose of this study was to define the proximal ulna anatomy with respect to olecranon osteotomy and fracture fixation. Thirty-nine cadaver elbows were dissected. The mean ulnar length (triceps insertion to ulnar styloid) was 26.0 cm (range, 27.1-29.0 cm). The mean distance from the triceps insertion to the ulna's varus angulation point was 7.6 cm (range, 6.5-9.0 cm). The distance ratio from the triceps insertion to the proximal ulnar angle to the overall ulna length was consistent, averaging 0.29 (range, 0.23-0.33). The mean diameter of the medullary canal at the ulnar angulation point could accommodate a 7.0- or 7.3-mm intramedullary screw. The mean width of the olecranon bare area (lacking articular cartilage) was 0.53 cm (range, 0.13-0.97 cm), and the mean distance from the triceps insertion to the corresponding area of the bare spot on the dorsal cortex was 2.1 cm (range, 1.4-2.5 cm).