It is a marvel that there are parts of the human gross anatomy that are still being discovered! The anterolateral ligament, a ligament near the ACL (of “I tore my ACL playing basketball” fame) was only recently re-discovered. The notion of this particular ligament was first made by French surgeon Paul Segond in 1879 but it has evaded definitive surgical classification until 2013 or so! Understanding it is starting to help surgeons repair knee injuries better!
I checked my Netter’s Atlas of Human Anatomy 6th Edition and Clinically Oriented Anatomy 7th Edition and came up empty!