Flemish Doctor Corrects 500-Year-Old Anatomy Error in Thigh

For nearly five centuries, anatomy textbooks have described the inner thigh muscles incorrectly — a mistake traced back to the pioneering 16th-century Flemish anatomist Andreas Vesalius. Now, a Belgian sports medicine physician has not only corrected the error but turned his discovery into a new global standard for treating chronic groin pain, a condition affecting over a million patients worldwide.

A 500-Year-Old Mistake

Since Vesalius published his landmark work De humani corporis fabrica in 1543, medical students have been taught that three separate adductor muscles of the inner thigh — the adductor longus, adductor brevis, and gracilis — each attach individually to the pubic bone via their own tendons. Dr. Thomas Mathieu (35), a sports medicine physician at AZ Rivierenland and lecturer at the University of Antwerp, discovered during his doctoral research that this is not the case.

According to Het Laatste Nieuws, Mathieu’s cadaver study — involving 44 dissections on 22 bodies — revealed that in 90 percent of cases, the adductor brevis and gracilis muscles are fused together, forming a single thick cable that attaches to the pubic bone. “So what’s in the anatomy books is not correct,” Mathieu told HLN. “You should not see the three thigh muscles as three separate cables, but as one thick cable.”

The Mathieu Syndrome

Beyond correcting a centuries-old anatomical error, Mathieu identified a previously unknown injury to the inferior pubic ligament (IPL) — now known internationally as the “Mathieu syndrome.” As reported by Ortho-Rheumato, MRI analyses show that approximately one in three athletes with pubic pain have a tear in this ligament.

“The ligaments around the knee and ankle have been extensively studied,” Mathieu explained. “But less research has been done on the ligaments of the pubic bone. For doctors, treating groin pain is a serious challenge. It’s sometimes called the Bermuda Triangle of sports medicine.”

Chronic groin pain affects thousands of people in Belgium alone and over a million patients worldwide, particularly footballers, hockey players, tennis players, runners, horse riders, and postpartum women.

A Revolution in Treatment

The discovery has fundamentally changed how groin pain is diagnosed and treated. Mathieu’s findings, published in the peer-reviewed journal Annals of Anatomy in February 2024, have led to:

• More precise diagnosis using ultrasound and MRI protocols that can identify the fused muscle cable and specific ligament injuries
• Targeted injections of anti-inflammatory medication guided by real-time imaging
• Avoiding unnecessary surgery — cutting individual tendons can destabilize the common tendon plate
• More effective rehabilitation that treats all three muscles together as one unit

“Now we realize that we should not operate too quickly,” Mathieu told HLN. “Previously, it was assumed that cutting one tendon would be sufficient to recover, but the results of the surgeries were not good.”

International Recognition

The significance of Mathieu’s work has been recognized worldwide. He became the first Belgian to receive the International Sports Medicine Leadership Award from the American Medical Society for Sports Medicine (AMSSM). According to Wikipedia, he also led the sports medicine delegation during the Belgian princely economic mission to Australia.

His anatomical insights have been used as a reference in a US multicenter study on groin pain in Major League Soccer (MLS) players — the league where Lionel Messi plays — and have formed the basis for recent surgical guidelines for interventions in the pubic region.

What This Means for Patients

The most profound impact is on patient outcomes. Some individuals who were told they would never fully recover from chronic groin pain are now recovering within months thanks to the new diagnostic and treatment protocols.

“Chronic groin pain affects thousands of people in our country alone,” Mathieu said. “Worldwide, it involves a million patients or more.”

As SportinAntwerpen noted, the discovery serves as a powerful reminder of the scientific method in action. “Since Andreas Vesalius in the sixteenth century, anatomical dissection studies have been conducted,” Mathieu reflected. “But as a scientist, you sometimes have to dare to question yourself and even the anatomy books to make progress.”

The Future

Mathieu’s findings are already being integrated into medical curricula and clinical practice worldwide. The new ultrasound guidelines he developed are now used globally, and his classification system helps radiologists and physicians recognize the problem correctly. For the millions suffering from chronic groin pain — from elite athletes to new mothers — this 500-year-old correction could not have come at a better time.