Welcome to FTW Explains: a guide to catching up on and better understanding stuff going on in the world. You may have seen the news about Philadelphia 76ers guard Markelle Fultz being diagnosed with Thoracic Outlet Syndrome and wondered what that was. We’re here to help.

Who is Markelle Fultz?

He was chosen by the Sixers first overall in the 2017 NBA Draft out of Washington. Since being drafted and dealing with shoulder problems that have affected his shooting form, he’s struggled to live up to the expectations placed upon him. There’s been rampant speculation about what could be the cause of his shooting struggles, which has included pump-faking at the free throw line and changing his routine at the charity stripe.

This is worse than we have ever seen Fultz's free throw form look. pic.twitter.com/FhCYpNpd5b — Kyle Neubeck (@KyleNeubeck) November 13, 2018

The latest from Markelle Fultz at the FT line: pic.twitter.com/OJZPKEfvf1 — SportsCenter (@SportsCenter) November 17, 2018

Was it his shoulder acting up? A case of the yips? There wasn’t really a definitive answer until now.

What happened now?

On Tuesday, Fultz was diagnosed with thoracic outlet syndrome, and the guard is out indefinitely as he goes through physical therapy to correct the problem.

Thoracic outlet syndrome?

From the Mayo Clinic:

Thoracic outlet syndrome is a group of disorders that occur when blood vessels or nerves in the space between your collarbone and your first rib (thoracic outlet) are compressed. This can cause pain in your shoulders and neck and numbness in your fingers. Common causes of thoracic outlet syndrome include physical trauma from a car accident, repetitive injuries from job- or sports-related activities, certain anatomical defects (such as having an extra rib), and pregnancy. Sometimes doctors can’t determine the cause of thoracic outlet syndrome.

Have we seen this in sports before?

We have! It’s become more common in baseball players, specifically pitchers.

What do they do to recover?

Like Fultz, treatment can start with physical therapy, but in more severe cases, surgery can help. Pitchers like Matt Harvey, Tyson Ross and Phil Hughes have had a rib removed to alleviate the pain (and some patients like Hughes keep the bone as a souvenir).

Will Fultz require surgery?

We don’t know yet. It sounds like the first step is rehabbing it.