New Body Part Discovered, But You May Not Even Have It

If you think you’re familiar with the human anatomy, think again. Scientists at University Hospitals Leuven in Belgium discovered a new body part inside the muscles and tendons of the knee.

The new part, called the anterolateral ligament (ALL), was dissected for the first time in a new study published this week in the Journal of Anatomy. According to the researchers, three percent of the population doesn’t have the ligament.

Science Daily reports that two knee surgeons working at the hospitals discovered the ligament, which appears to play a role in patients with tears in their anterior cruciate ligament (ACL).

Despite successful surgeries to repair the ACL, plus rehabilitation, some patients continue to experience “pivot shift,” where the knee “gives away” during activity. Dr. Steven Claes and Professor Dr. Johan Bellemans conducted research for the past four years into serious ACL injuries to find out why this happens.

They started with an article published in 1879 by a French surgeon, who suggested that another ligament could exist on the anterior of the human knee. Elaborating on the article, the Belgian doctors discovered the suggestion was correct after using macroscopic dissection techniques in a broad cadaver discovery.

Medical Daily notes that the ALL is a “pearly band” that connects the femur to the anterolaterial tibia. In their conclusion, the study authors explained, “Given its structure and anatomic location, the ALL is hypothesized to control internal tibial rotation and thus to affect the pivot shift phenomenon, although further studies are needed to investigate its biochemical function.”

If it seems strange that scientists are just discovering a new body part after studying humans for thousands of years, consider that a new layer of the eye was discovered earlier this summer. The feature, called the Dua’s layer, is a structure behind the cornea that was found using an electron microscope after scientists injected air bubbles into donated eyes to separate the different layers of the cornea.

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