Two Belgian surgeons have discovered a new body part—though there's potentially a 3% chance you don't actually have it. In a paper published in the Journal of Anatomy, they confirm the existence of the knee's anterolateral ligament. They were far from the first to speculate on the mysterious "enigmatic" ligament, though: That honor goes to Frenchman Paul Segond, who wrote an 1879 paper that speculated about the "pearly, resistant, fibrous band," reports Medical Daily.
To put Segond's theory to the test, Dr. Steven Claes and Dr. Johan Bellemans dissected the knees of 41 cadavers. Science Daily reports they found the ALL—which sits toward the front and side of the knee, and connects the femur and anterolateral tibia—in 40, or 97%, of them. (You can see a somewhat grisly photo here.) But the news isn't just neat, it's potentially quite useful: The surgeons say their findings help explain why those who have treated an ACL injury still have issues, specifically experiencing "pivot shifts," in which the knee gives way. Based on the ALL's structure and location, the doctors assert that an ALL injury may be what causes the pivot shift. The men plan to next develop a method of repairing injured ALLs. (Amazingly, this is actually the second new body part to be found this year.)