The average NBA player meets a key diagnostic criteria for this disease. Care to guess what it is?

It's Marfan syndrome, a genetic disorder caused by the misfolding of the protein fibrillin-1, which is essential to the formation of elastic fibers in connective tissue. In essence, the bodies of people with Marfan syndrome aren't as compact as they should be.

Those affected by Marfan syndrome are often unusually tall, with long, slender limbs. As such, doctors regularly look at the ratio of a person's wingspan -- the length of the outstretched arms from fingertip to fingertip -- to their height when making a diagnosis. A ratio larger than 1.05 is indicative of Marfan.

According to an analysis completed by Sports Illustrated in 2012, the average NBA player has a wingspan-to-height ration of 1.063. While most of them probably don't have Marfan syndrome, there's little doubt that they are absurdly long and lanky. In effect, this makes NBA players both wider and taller than they really are.

You might recall Leonardo da Vinci's iconic painting of the Vitruvian Man, which accurately depicts the idealized proportions of a human male.

"Leonardo da Vinci's Vitruvian Man has an arm span equal to his height. So do I. So, probably, do you," David Epstein, a senior writer at Sports Illustrated, wrote in his 2013 book The Sports Gene.

Almost all NBA players do not; even the shortest.

If you saw Nate Robinson walking along the street, you probably wouldn't guess him to be a successful NBA point guard. Standing a mere 5'8'' on a good day, Robinson is shorter than the average American adult male. But with a wingspan of 6'1", his reach is well above average. The trend continues even amongst taller players. Washington Wizards sharpshooter John Wall is 6'3" with a wingspan of 6'9". All-star Kevin Durant is 6'10" with a wingspan of 7'5". The prolific 7'7" center Manute Bol holds the NBA record for longest wingspan: 8 feet 6 inches.

Only two NBA players playing in 2011 had a shorter wingspan than their height: J.J. Redick and Yao Ming.

"The bottom line is that not only are NBA players outlandishly tall, they are also preposterously long, even relative to their stature," Epstein wrote.

As you and your friends are gushing over the latest acrobatic dunks, forceful blocks, and insane assists from the NBA playoffs, infuse the conversation with a little science, and explain why a long wingspan means that NBA players aren't as short as they seem.

Primary Source: David Epstein, The Sports Gene: Inside the Science of Extraordinary Athletic Performance, 2013