My explorations into the vocabulary for parts of the body began with the armpit, a (concave) area or region (or part) of the body that many people would be reluctant to call a bodypart (or body-part or body part) — a topic for another posting. It struck me that the ordinary English vocabulary was poor in words for concavities (though usually there are technical terms in anatomy for these areas), while being rich in words for areas of the body that project (nose, ears, lips, fingers, toes, elbows, knees, nipples, and so on).
Then yesterday Victor Mair posted on Language Log about the area (or web) between the thumb and forefinger, which has a label in Chinese (a metaphorical label Victor translated as “tiger’s maw”), but certainly doesn’t in English.
Armpit. This area might more reasonably have been called the shoulder pit, but then language develops as it will, not by conscious reasoning.
In any case, the area has two ordinary-language labels, armpit and underarm (and apparently in Scots and Northern English, oxter), plus the anatomical label axilla, which few people know or use.
Other pits. Analogous to the armpit are the inside of the elbow and the inside of the knee. These phrases — inside of the elbow, inside of the knee — are of course available for talking about these areas, but there are no standard lexical items for them in ordinary English. There are anatomical terms, cubital fossa and popliteal fossa, respectively, but these are even less commonly known than axilla. (Latin fossa ‘ditch, trench’. Anatomical terms are packed with metaphors.)
And there are are compounds, elbow pit and knee pit, formed on analogy to armpit, but though widely used, they haven’t made the trip from slang to standard.
The philtrum. Another concavity with no ordinary-language name: the vertical groove between the lip and the nose.
The perineum. From the Wikipedia entry:
In human anatomy, the perineum (Late Latin, from Greek περίνεος – perineos) is a region of the body including the perineal body and surrounding structures. There is some variability in how the boundaries are defined, but the term generally includes the genitals and anus.
… A wide variety of slang terms are commonly used for this area of the human body, most commonly “chode,” “gooch,” or “taint,” or even “the spot where God sewed us up” but they generally refer to a smaller, less inclusive area — just the surface skin region between the anus and the scrotum or vaginal opening.
Another theme here in labels for parts of the body: some labels apply to wider or narrower areas; that is, they’re ambiguous between more inclusive and more exclusive senses.
Back to the Tiger’s maw. English references to this area generally use the phrase between the thumb and forefinger (or index finger):
The five dots tattoo is a tattoo of five dots arranged in a quincunx, usually on the outer surface of the hand, between the thumb and the index finger. (link)
In the United Kingdom, the quincunx tattoo, on the web between thumb and forefinger, is a prison tattoo reflecting the view of women by those wearing it – Find Her, Follow Her, Finger Her, Fuck Her, Forget Her. (link)
Keep massaging the flap of skin between thumb and forefinger. (link)
Gokoku: Pressure point in fleshy area between thumb and forefinger. (link)
The last cite points to the significance of this area in martial arts and acupuncture: it’s the site of an important pressure/acupuncture point. So it would make sense for Chinese to have a label for it.
English has no widely used term, though the obvious thumb pit has been invented on occasion:
[on guitar picks] Alternatively you can just hold it with your unused fingers e.g. pinky and ring, or in your thumb pit. (link)
Even an anatomical label is hard to find, though given Latin pollex (genitive pollicis) ‘thumb’, we could hope for polliceal fossa.