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The origin of the conflict, a new evolutionary paradigm

To understand why the human foot is so vulnerable to FHL, we may need to go back five million years. A meeting with anthropologist Yvette Deloison, around a theory that rethinks the place of bipedalism in human evolution.

A rarely asked question

FHL is not a disease in the classic sense of the word. It is not an infection, it is not a cancer, it is not a degeneration. It is a mechanical conflict between a tendon and a bony tunnel, occurring at a precise moment of the step, in enough people that we encounter it every day in consultation. So where does this conflict come from? Why does our anatomy end up trapping itself?

The answer does not lie in the present. It lies in five million years of evolution.

A meeting, a book, a thesis

While preparing the 2023 Medicol Congress on FHL, Dr Jacques Vallotton met Yvette Deloison, an anthropologist specializing in human evolution. From this meeting arose a line of thought that sheds light on the condition from an unexpected angle, the evolutionary one.

Author

Yvette Deloison

Anthropologist, specialist in human evolution and the origins of bipedalism. Author of a theory that proposes a semi-aquatic proto-hominoid as the ancestor of the human lineage, distinct from that of the australopithecines. Reference: La préhistoire du piéton.

Two evolutionary paradigms

Classical evolution teaches that modern humans descend from the australopithecine lineage, themselves derived from tree-dwelling primates. Bipedalism would therefore be a recent and gradual acquisition, the consequence of a progressive descent from the trees toward the savanna. Yvette Deloison offers another reading.

Classical paradigm

Humans would descend from the australopithecines

Modern humans would derive from the australopithecine lineage, partially bipedal primates that appeared about four million years ago. Bipedalism would be a relatively recent acquisition, linked to the move out of the forests toward the African savannas.

Alternative hypothesis

Original bipedalism, semi-aquatic

Our lineage would descend from a bipedal proto-hominoid living in a semi-aquatic environment, distinct from that of the australopithecines. Bipedalism would not be a late conquest but an original characteristic. This thesis, supported by eminent specialists, has never been disproven.

The fossil footprints of Crete

The discovery of fossil footprints in Crete dating back more than five million years has reopened the debate. These footprints show anatomically modern features (the presence of a plantar arch, a hallux aligned with the other toes, a roll-over of the step) at a time when, according to the classical paradigm, bipedal humans should not have existed.

5 million years

The footprint that unsettles the official narrative

This fossil footprint, older than the earliest documented bipedal australopithecines in Africa, shows a morphology already very close to that of the modern human foot. It suggests that a bipedal lineage existed well before what the classical timeline admits, and that it may have followed a distinct evolutionary path.

The full interview on video

Dr Jacques Vallotton and Yvette Deloison discuss these questions in detail in a series of three videos. The main interview addresses original bipedalism, and two supplements explore the genetic angle and the angle of human reconstructions.

main interview

Original bipedalism, a new paradigm

supplement 1

Evolution and genetics

supplement 2

Human reconstructions

The link with FHL

What is the connection between this anthropological thesis and the FHL that the Centre du pied encounters every day? The connection is direct. If our lineage evolved in a semi-aquatic environment, the anatomy of our foot was optimized for constraints different from those we impose on it today. Prolonged walking on hard ground, Western footwear, even surfaces, long distances spent standing — so many demands that our foot may not have been designed to bear fully.

A working hypothesis

The retro-talar tunnel and the fibrous pulley that constrains the FHL tendon could be an evolutionary legacy of a different foot function, optimized for a use we no longer have. FHL would then be less an anomaly than a conflict between an ancient anatomy and a modern use.

« The human foot is an evolutionary compromise that has not quite finished evolving. FHL is one of the prices we pay for walking upright on sidewalks. »

Dr Jacques Vallotton, Centre Orthopédique d’Ouchy

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From theory to practice

To understand the origin of the conflict in your own case, its manifestations and the treatment options available, the Centre Orthopédique d’Ouchy offers a complete assessment.

In brief

Anthropologist

Yvette Deloison

Thesis

original bipedalism

Footprints

5 million years

Location

Crete

Hypothesis

semi-aquatic environment

Videos

1 interview + 2