Many years ago, I did a short job placement at the medical library of St. Michael's Hospital in Toronto. There were all kinds of amazing things to discover in the collection, but perhaps the most striking thing I found in my time there was a copy of the Oucher pain scale - a variety of photos of children ranging in expression from placid to agonized (there is also a version of the scale featuring simple 'happy face' to 'sad face' expressions*).
The scale was a bizarre contradiction to me: expressions of discomfort and agony on small faces - pained faces, ranked in such a manner, something pornographic about it - and in a hospital of all places. My initial reaction was to find it somewhat perverse, strange and disturbing. My mind kept coming back to it, and what a curious thing it was.
But then pain is a funny thing, ultimately subjective and thus very difficult to measure. Most of us, experiencing pain, would regard it as being either 'really bad' or just plain 'ARGGHHHHH!' - any more than that and words would likely fail us utterly.
This isn't very helpful to those in the medical profession of course, and, in the interest of applying some objectivity to the subject, many different methods of measuring pain have been created. Some of these rely on testimony from the patient, often using key words to evaluate the severity of the pain. Another popular method is to simply give the pain a numeric value from 0 to 10.
In the case of children however, who lack the sophistication or vocabulary to apply words to their pain, pictures may provide assistance. This is the rationale behind the Oucher scale, created in 1980 by one Dr. Judith E. Beyer. Initially featuring Caucasian faces only, it was updated ten years later with a Hispanic version and an African-American version. In addition, the original poster format was gradually shrunk down to a pocket-size version, making it easier to use.
The language of pain and the descriptions we may employ to convey our pain are often quite remarkable, even poetic. From the Schmidt Sting Pain Index, designed to differentiate insect stings:
1.0 Sweat bee: Light, ephemeral, almost fruity. A tiny spark has singed a single hair on your arm.
1.2 Fire ant: Sharp, sudden, mildly alarming. Like walking across a shag carpet & reaching for the light switch.
1.8 Bullhorn acacia ant: A rare, piercing, elevated sort of pain. Someone has fired a staple into your cheek.
2.0 Bald-faced hornet: Rich, hearty, slightly crunchy. Similar to getting your hand mashed in a revolving door.
2.0 Yellowjacket: Hot and smoky, almost irreverent. Imagine W. C. Fields extinguishing a cigar on your tongue.
2.x Honey bee and European hornet: Like a matchhead that flips off and burns on your skin.
3.0 Red harvester ant: Bold and unrelenting. Somebody is using a drill to excavate your ingrown toenail.
3.0 Paper wasp: Caustic & burning. Distinctly bitter aftertaste. Like spilling a beaker of hydrochloric acid on a paper cut.
4.0 Tarantula hawk: Blinding, fierce, shockingly electric. A running hair drier has been dropped into your bubble bath.
4.0+ Bullet ant: Pure, intense, brilliant pain. Like fire-walking over flaming charcoal with a 3-inch rusty nail in your heel.
*the Wong-Baker pain scale is virtually identical to this smiley-sad face scale. My research, such as it is, suggests the Oucher may be strictly photographic while the Wong-Baker is drawn.