Triceps brachii insertional footprint: Under-estimated complexity.

Background: The detailed complexity of triceps brachii insertional footprint continues to challenge surgeons as evidenced by continued reports of triceps-associated complications following elbow procedures. The purpose of this study is to describe the three-dimensional footprint of the triceps brachii at its olecranon insertion at the elbow. Methods: 22 cadaveric elbows were dissected leaving only the distal insertion of the triceps intact. The insertion was defined and probed with a three-dimensional digitizer to create a digital three-dimensional footprint allowing width, height, and surface area of the footprint to be recorded relative to the bare area. The insertional soft tissues of tendon versus muscle along with the shape of the footprints were qualitatively described. Results: The mean width and surface area of the lateral segment was greater in males than in females (30.07 mm vs. 24.37 mm, p  =  0.0339 and 282.1 mm vs. 211. 56 mm, p  =  0.0181, respectively). No other statistically significant differences between the sexes were noted. The triceps insertional footprint was "crescent-shaped" and consisted of three regions: central tendon, medial muscular extension, and lateral muscular extension. Discussion: These findings can help explain the importance of avoiding these muscular structures during triceps-off approaches and provides the framework for future clinical studies.