While Tottenham vs. Ajax was quite the entertaining match on Tuesday in the Champions League, it wasn't without a scary moment. Spurs defender Jan Vertonghen picked up a nasty, bloody head injury. The defender was checked out by the medical staff, and he was let back on the field before nearly collapsing. He was then substituted off. 

The incident has once again brought the topic of head injuries back on to soccer's main stage. While we hear about it so much in the National Football League and college football, it's a growing concern in soccer and usually occurs on 50-50 balls or set pieces. 

In the past we've seen plenty of collisions, like the one to Petr Cech which resulted in him having a fractured skull, hence why he has worn headgear for over the last decade. Cech nearly died as a result of the injury

The one to Vertonghen on Tuesday happened when he went up for a header and crashed heads with fellow defender Toby Alderweireld. Take a look. He obviously looks concussed, and he had to be helped off the field because it looked like his legs were giving in:

But it turns out, according to the Evening Standard's Dan Kilpatrick, that the player actually passed all concussion tests after the match.

Former U.S. men's national team player Taylor Twellman took to Twitter to give his stance. The 39-year-old has long been promoting the awareness of concussions, which ended his career early. 

Now, the fact that he was allowed to come back on to the field is a bit questionable. Many players think they could play through it, but any head injury can be potentially serious. Perhaps there needs to be modifications as to how the sport handles head injuries, but the image of Vertonghen stumbling to stay up is quite concerning. 

There have been various studies, like this one from the Institute of Medicine (US) Board on Neuroscience and Behavioral Health, that detail the concerns of simply repeatedly heading the ball, let alone the grave concerns for head-on-head collisions. 

While Vertonghen seems to be fine, and lucky for him, this is just another example of perhaps clubs needing to be more cautious when it comes to injuries and a reminder for the leaders to find a more efficient way to diagnose and treat these, no matter what a player says.

You can watch the Champions League on fuboTV (Try for free). 

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