The flurry of punches that knocked out Conor McGregor only told half of the story of Dustin Poirier's shock victory at UFC 257.

By the time the Diamond caught the Notorious and sent him stumbling onto the canvas, he had already demobilised him with a series of leg kicks. 

The irony, of course, is that when the pair met in 2014, it was one of Poirier's left hooks which rattled McGregor - and while his fists spelled the end of his opponent this time, it was a different weapon in his arsenal which caused problems in both rounds. 

After the fight, the Irishman complained of his leg being "completely dead" and "compromised".

When the pair met backstage, he could also be heard telling Poirier: "You broke my leg, you b******. Great going." 

McGregor's leg swelled right up and images of his lower leg which emerged post-fight went some way towards explaining why he had been unable to evade the American's onslaught. 

It wasn't immediately clear what kind of injury he had sustained though, or why Poirier's leg kicks were so effective. 

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However, Physician Brian Sutterer has released a video detailing exactly what kind of punishment McGregor had sustained. 

"As soon as he put weight on that right leg, he was in some serious discomfort," Sutterer explained. 

"[Poirier's leg kicks] made contact exactly on this kind of lateral aspect of McGregor's lower leg near the outside of the calf. Even right away we can see McGregor have some pain here, having difficulty putting weight on that leg. And that just accumulated throughout the fight, so at the end, McGregor's leg was basically dead. 

"A kick in this area is specifically targeting something we call the common fibular nerve...it's the nerve that supplies muscle control to part of the lower leg, but also some of the sensation.

"Pay attention to exactly where Poirier's leg is making contact with McGregor's, it's just below his knee.

"This is where these UFC fighters are trying to strike to have these effective calf kicks. The green nerve [in the video] is that common fibular nerve, and what's important about it is how superficial it is, meaning how close it is to the skin. 

"A lot of other big nerves in our body are deep beneath skin or deep beneath muscle, and so they're pretty well protected. But this nerve in particular is really close to the surface and really susceptible to these stuns and getting injured."

That certainly explains why McGregor was unable to feel his leg after such a prolonged assault on the nerves from Poirier.

It also emphasises just how accurate his leg kicks were. 

If a trilogy fight does happen, he'll be much more aware of Poirier's secret weapon next time around.