The Mysterious Math Behind the Brazilian Butt Lift

In the history of gluteal enhancement, Mexico City stands out. It protrudes. It was here, in 1979, that a plastic surgeon, Mario González-Ulloa, first installed a pair of silicone implants designed specifically for the buttocks. The textbook Body Sculpting with Silicone Implants calls González-Ulloa the “grandfather of buttock augmentation.” The early 2000s saw a new generation of Mexico City buttock transformation luminaries, notably Ramón Cuenca-Guerra. In his 2004 paper “What Makes Buttocks Beautiful?” Cuenca-Guerra laid out four characteristics that “determine attractive buttocks” as well as the five types of “defects,” with strategies for correcting each one. I, for instance, have defect type 5, the “senile buttock.” (González-Ulloa’s depiction of this took the form of charcoal nudes contrasting “the typical ‘happy buttock’”—high, rounded, dimpled—with its counterpart, the low-slung, drooping “sad buttock.”)

While I understand the value of standardizing procedures and setting guidelines for surgical practice, I tripped over Cuenca-Guerra’s methodology. How and by whom had the determinants been determined? Like this: 1,320 photographs of “nude women ages 20 to 35 years, as seen from behind” were presented to a panel of six plastic surgeons, who “pointed out which buttocks they considered attractive and harmonious, and features on which this attractiveness depended.” Oho!

I thought it would be interesting to talk to Cuenca-Guerra about the notion of a visually ideal female figure. As something that could or should be surgically created (or, in the case of the senile buttock, re-created). As something that even exists. I sent an email using the address on a more recent journal paper. There was no reply. Ramón Cuenca-Guerra’s buttocks are in worse shape than mine. He has been dead for some time. I was able to reach a colleague of his, José Luis Daza-Flores. Here was the third generation; just as Cuenca-Guerra had studied under González-Ulloa, Daza-Flores had studied under Cuenca-Guerra, extending the lineage and making Daza-Flores, I guess, “the son of buttock augmentation.”

Daza-Flores collaborated with Cuenca-Guerra on a paper called “Calf Implants,” in which the team did for the lower leg what Cuenca-Guerra had done for the butt: laid out “the anatomical characteristics that make calves look attractive” and the “defects” to be addressed. Here again, plastic surgeons were recruited to judge images—2,600 of them, a vast photographic millipede of female legs.

The paper took an unexpected turn. Referring to a marked-up photograph of a lower leg deemed attractive, the authors tried to show that its measurements conformed to what is known in mathematics as the divine proportion (or golden ratio)—1.6 (I’m rounding it off) to 1. When you divide a line into two parts such that the whole length divided by the long part is equal to the long part divided by the short part, both those ratios will be 1.6 to 1. I found an illustration of the divine proportion on a website called Math Is Fun (and convincing no one). The golden dividing line splits the length such that one chunk is roughly two-thirds and the other is around one-third. The ancient Greeks divided the “ideal” face into similarly proportioned thirds. This was the first time I’d seen the divine proportion applied to a leg.

The paper contained sentences like this: “Seventeen women had thin legs, in the shape of a tube, and a mere 1:1.618 ratio in the A-P and L-L projections.” Though I confess to not grasping the particulars of the discussion, I believe that to be a mathematically precise description of cankles.