Plastic surgeons have discovered the formula behind what are considered beautiful legs – and it’s not just about length and slenderness.

From the ancient Greeks through the Renaissance to modern day there is one attribute that has consistently defined what is thought of as beautiful, they found: a straight line from the top of the thigh to the ankle.

Surgeons studied 600 pairs of legs over 12 year from magazines, live models, athletes, art and Barbie dolls – all those widely accepted as the most attractive in the western world.

“Not a single attractive leg was found to deviate from the vertical, and each was in absolute continuity with the thigh,” the study, published in the medical journal Aesthetic Plastic Surgery, revealed.

The study surmised that the attractiveness of long, straight, slender legs may be attributed to a sense of aesthetic harmony, which is “intensified by the blending of fragility, represented by thinness, and strength, represented by straightness”.

“The straightness of the legs of models who advertise leg stockings and lingerie is notable,” it added.

Plastic surgeons have discovered the formula behind what are considered beautiful legs

The second key to beautiful legs is the distribution of curves from the knee to the ankle. Legs considered beautiful were found to curve through the top two thirds of the calf when viewed in profile, while the front of the leg appeared almost straight.

The calf on the inside of the leg should have a well-defined convex curve, and another short concave curve as it descends into the ankle. The outside of the perfect leg has a much longer, smoother convex curve.

The study looked at depictions of beautiful legs from as early as 2,000 BC in Greece and found “the shape and distribution of the curves of such ancient legs are exactly the same as those of men and women models today!”.