Despite being the largest ligament on the posterior aspect of the knee, relatively little is known about the normal anatomy of the oblique popliteal ligament (OPL).The purpose of this study was to investigate the detailed morphology of the OPL using several techniques: cadaver dissection (13 males, 8 females;mean age 75.9 [SD 9.6] years) and histology (samples from eight knees, randomly selected);and MRI scans in healthy volunteers (10 males, 3 females;mean age 23.6 [SD 3.2] years).