The Encyclopedia Britannica describes laughter as "rhythmic, vocalized, expiratory and involuntary actions". Way to make laughter sound singularly unfunny, EB. Seems unlikely, then, that laughing could cause one's arse to fall off. But we need to be sure, lest our next burst leaves us without our seating appendage.
Muscle-wise, some fifteen facial muscles contract, and the diaphragm and the muscles of the abdomen, respiratory tract, and back are given a workout. No mention of gluteuses minimus, medius, or, least of all, maximus.
The epiglottis, that flap that switches between breathing and eating, half-closes the larynx (voicebox), which is why breathing becomes gaspy. This whole area could hardly be anatomically further from the arse. Unless, of course, the subject is alledged to talk out of theirs. That would certainly mix things up. An investigation into which orifice an individual deploys for the purposes of vocalisation is beyond the remit of this blog, but could, perhaps, be the topic of a future blog.
The zygomatic major muscle, the main lifting mechanism of the upper lip, is stimulated. This explains that twitching of the upper lip you get. This becomes increasingly noticeable, when circumstances dictate that you resist the urge to laugh. Like when you're at a funeral. If anything, perhaps the top lip is likely to work itself loose as a result of laughter, as you struggle to keep it down and still, so as not to betray your underlying urge to laugh.
Which brings us on to the head in general. The head, of course, is also prone to detachment as a result of laughter. This, at least, makes some sense, since we are known to throw our head back in laughter. It's surely plausible, then, that something could make us laugh so much that we momentarily forget to exercise due diligence whilst throwing our head back, do so in an over-zealous manner, and the head, in fact, falls off. It's only logical.
Why, then, is it always one's arse that is described as falling off when one laughs excessively? The arse, we now know, has nothing whatever to do with the business of laughing. Were anything to fall off, it would clearly be one's head, or possibly just one's top lip.
LMAO? I don't think so. That's just plain silly. LMHO, or LMTLO? It's just possible. And that's science fact.
