The annular ligament—revisited

Background Studies investigating the annular ligament have presented confusing information about its anatomy and nomenclature. Cadaver elbow dissections were used to clarify the anatomy and terminology of the annular ligament. Methods Nineteen elbows were dissected (7 fresh frozen and 12 embalmed). Target structures were identified, photographed, and measured by independent observers. Results There are 3 layers to the lateral elbow ligaments: the superficial lateral ulnar collateral and radial collateral ligament; a deeper layer of the superior oblique band (SOB) and inferior oblique band (IOB) of the annular ligament; and the deepest capsular layer. The annular ligament measured 9.5 ± 1.4 mm anteriorly. The SOB (15/19) was 3.9 ± 1.0 mm wide by 10.5 ± 3.8 mm long. The IOB (13/19) was 3.6 ± 1.1 mm wide by 11.4 ± 4.2 mm long. The IOB inserts onto the anterior proximal ulna rather than the supinator crest. The anterior oblique band (8/19) was 3.8 ± 1.7 mm wide. Conclusion The SOB and IOB were present in the majority of specimens. The previously described accessory lateral collateral ligament is a localized thickening on the lateral ligament complex arising from the supinator insertion independent of the IOB that attaches to the annular ligament inferiorly and distally and attaches onto the proximal anterior ulna at the bicipital fossa floor, medial to the supinator crest.