NaBloPoMo Post #22: Let's Learn Some Orthoptics!
NaBloPoMo Post #22: 25th November 2008
I have malted milk biscuits and a cup of chai tea. Ahhh, the simple things in life.
Well, kiddoes, today I'm going to teach you some orthoptics! My topic of choice is a somewhat rare and unusual syndrome. Like a lot of syndromes, it has a stupid name. The complicated name for it is Pterygoid-Levator or Trigemino-oculomotor Synkinesis, but a more descriptive term is Marcus Gunn Jaw Winking Syndrome.
So, what the hell is that? Perhaps it's best if I show you a video - this guy's one is a beauty!
Pretty bizarre, huh? So how the hell does he do that? There's no trick to it or anything - he was actually born that way. Going back to the complicated name for the condition, Trigemino-oculomotor Synkinesis - the components of the first word refer to two of the twelve cranial nerves that power various things on your face. There's the trigeminal nerve, which is the fifth cranial nerve - this provides most of the sensation to your face and also powers the muscles you use for chewing, biting and swallowing. And then there's the oculomotor nerve, which powers four of the six muscles that move your eyes around and, more importantly, the muscle that hoists up your upper eyelid.
The Synkinesis part basically means a mixing up of which nerve powers what. So this bizarre winking motion of the guy's eyelid in the video as he eats is essentially caused by a miswiring of his nerves. His trigeminal nerve has wired itself up to the upper eyelid muscle along with the usual branch of the oculomotor nerve (sometimes that doesn't wire up fully because of the trigeminal pushing in, and they end up with a droopy lid when they're not eating). Thus when his jaw moves, the nerve signals passing to the jaw to initiate the chewing action are also passing up to his eyelid, and bing! Wink wink wink goes the eyelid and chew chew chew goes the jaw in perfect synchronisation.
So there we go, this is why it's called Marcus Gunn Jaw Winking Syndrome - pretty much what it says on the tin, yes? It's pretty rare, I've only seen two cases in the three years I was training. You'll get a kid coming in and Mum goes "Oh, he's got a droopy lid", and you'll look at them and find absolutely nothing, maybe a very slight droop but nothing as bad as what they're describing. Then they'll say they notice it most at dinner time and then the penny will drop! Give 'em a toffee or something and your diagnosis is confirmed, easy peasy XD
But the reason I decided to tell you all about this is because our lighting technician for the show has an absolute CORKER of a Marcus Gunn - it's as bad as that of the guy in the video. We were all at the after-first-night party and he was sitting across from me eating his pudding, and he was looking down at his food but I noticed that his right lid seemed to be wide open compared to the other one. This is unusual when you're looking down because normally the lids drop a little. I was looking at him discreetly trying to figure out what it was that he had, and then he started chewing and phooo boy did that lid go! I'd never seen one quite as profound as that before, it was awesome XD
Moral of this story: Once you start training as an orthoptist that's it, your whole perspective is changed and you suddenly start noticing EVERYBODY'S dodgy eyes even when you're off-duty! XD
I have malted milk biscuits and a cup of chai tea. Ahhh, the simple things in life.
Well, kiddoes, today I'm going to teach you some orthoptics! My topic of choice is a somewhat rare and unusual syndrome. Like a lot of syndromes, it has a stupid name. The complicated name for it is Pterygoid-Levator or Trigemino-oculomotor Synkinesis, but a more descriptive term is Marcus Gunn Jaw Winking Syndrome.
So, what the hell is that? Perhaps it's best if I show you a video - this guy's one is a beauty!
Click to viewPretty bizarre, huh? So how the hell does he do that? There's no trick to it or anything - he was actually born that way. Going back to the complicated name for the condition, Trigemino-oculomotor Synkinesis - the components of the first word refer to two of the twelve cranial nerves that power various things on your face. There's the trigeminal nerve, which is the fifth cranial nerve - this provides most of the sensation to your face and also powers the muscles you use for chewing, biting and swallowing. And then there's the oculomotor nerve, which powers four of the six muscles that move your eyes around and, more importantly, the muscle that hoists up your upper eyelid.
The Synkinesis part basically means a mixing up of which nerve powers what. So this bizarre winking motion of the guy's eyelid in the video as he eats is essentially caused by a miswiring of his nerves. His trigeminal nerve has wired itself up to the upper eyelid muscle along with the usual branch of the oculomotor nerve (sometimes that doesn't wire up fully because of the trigeminal pushing in, and they end up with a droopy lid when they're not eating). Thus when his jaw moves, the nerve signals passing to the jaw to initiate the chewing action are also passing up to his eyelid, and bing! Wink wink wink goes the eyelid and chew chew chew goes the jaw in perfect synchronisation.
So there we go, this is why it's called Marcus Gunn Jaw Winking Syndrome - pretty much what it says on the tin, yes? It's pretty rare, I've only seen two cases in the three years I was training. You'll get a kid coming in and Mum goes "Oh, he's got a droopy lid", and you'll look at them and find absolutely nothing, maybe a very slight droop but nothing as bad as what they're describing. Then they'll say they notice it most at dinner time and then the penny will drop! Give 'em a toffee or something and your diagnosis is confirmed, easy peasy XD
But the reason I decided to tell you all about this is because our lighting technician for the show has an absolute CORKER of a Marcus Gunn - it's as bad as that of the guy in the video. We were all at the after-first-night party and he was sitting across from me eating his pudding, and he was looking down at his food but I noticed that his right lid seemed to be wide open compared to the other one. This is unusual when you're looking down because normally the lids drop a little. I was looking at him discreetly trying to figure out what it was that he had, and then he started chewing and phooo boy did that lid go! I'd never seen one quite as profound as that before, it was awesome XD
Moral of this story: Once you start training as an orthoptist that's it, your whole perspective is changed and you suddenly start noticing EVERYBODY'S dodgy eyes even when you're off-duty! XD