A “new” knee ligament: the anterolateral ligament

Who knew? Hardly anyone! The anterolateral ligament is entirely missing from my library of anatomy texts. But it probably shouldn’t be so obscure. It’s right next door to the well-known lateral collateral ligament (LCL) and nearly as large. It comes standard, almost all knees have it. And it might be relevant to some common knee problems and injuries (or not, debate rages on).

So why isn’t this thing in the texts?

The details of anatomy are surprisingly tricky and unfinished. In 1879, French surgeon Segond described a “pearly, resistant fibrous band in the anterior lateral human knee,” and it only got a few muddled mentions in the literature for well over a century after that: imprecise and contradictory reports only.

The ALL was finally properly “discovered” in 2013 by Claes, who studied 41 cadaver knees to “clarify the long-standing enigma surrounding the existence of a ligamentous structure connecting the femur with the anterolateral tibia” and they “hypothesize that the ALL functions as a stabilizer for internal rotation.”

And boom, there you go: “new” knee ligament!