Anterior and posterior bands of the anterior bundle in the elbow ulnar collateral ligament: ultrasound anatomy

Background: The anterior oblique bundle (AOL) of the ulnar collateral ligament (UCL) is composed of anterior and posterior bands. This study evaluated the anatomy of the anterior and posterior bands in the AOL of the UCL for their separate visualization with ultrasound (US). Methods: We dissected 18 cadaveric elbow joints and recorded the direction of each band from the lateral view to determine the proper position for the US transducer. To determine the proper inclination of the transducer, we measured the inclinations of each band at the proximal and distal insertions from the transverse view. A paired t test was used for comparisons between both bands. Values of P<.05 were considered statistically significant. Results: The mean angles of the directions in the anterior and posterior bands were 10 degrees +/- 4 degrees and 24 degrees +/- 9 degrees, respectively. At the medial epicondyle, the mean inclination angles of both bands were 61 degrees +/- 5 degrees and 67 degrees +/- 5 degrees, respectively. At the sublime tubercle, the mean inclination angles of both bands were 14 degrees +/- 7 degrees and 44 degrees +/- 9 degrees, respectively. The inclination angles at the proximal ulna and the directions in both bands were significantly different (P<.001). Conclusions: This study shows that the directions of both bands and inclination angles of the bony attachments in both bands can assist with correct placement of the US transducer and allow for separate visualization of each band. (C) 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.