Ah, Dexter. Few shows juggle serial killing, dark humor, and wildly inaccurate hospital scenes quite like you. In Season 4, Episode 2, our favorite blood-spatter analyst wrecks his van—with a dead body conveniently riding shotgun in the back—and winds up in the ER. What follows is a crash course in how not to portray medicine on television.

Let’s dissect, shall we? (Pun very much intended.)

The ER doctor shines a light into Dexter’s eyes. Normal practice? Sure. But then we’re treated to the statement that his pupils dilate. Pupils constrict when you shine a light into them. They dilate in darkness. This is how the human body properly works.

Next, the doctor looks at Dexter’s CT scan and announces, “You’ve sustained a concussion.” implying that concussions are diagnosed this way. Concussions can be clinically diagnosed, based on symptoms like headache, confusion, dizziness, and loss of consciousness. You don’t need a CT scan to tell you that, and a CT isn’t going to show a concussion anyway. If it does, congratulations—you’re likely now dealing with a bleed, not a simple concussion.

But hey, why rely on pesky medical standards when you can dramatically gesture at a glowing scan instead?

Then comes one of my favorite relics of outdated medical lore: the “Don’t let him sleep” after head injury rule. Dexter is told not to sleep for twelve hours, as if a good nap might somehow erase him from existence.

In reality? We don’t keep people awake anymore after they’ve suffered a head injury if they feel like they need to sleep. That advice has gone the way of lobotomies. Any injured body part needs rest to heal. The brain rests by sleeping. Sleep is good and beneficial for the head injured patient. The guidance is: let the patient rest, check in periodically if symptoms worsen, and maybe—just maybe—don’t torture the poor guy who just got his bell rung trying to hide his crimes.

Ultimate lesson– don’t get into a car accident with a body in the back of your van that the police are going to tow.

Which show do you think butchers medical accuracy the most and which on gets it right?