(n.) the second part of the small intestine
Medical, anatomical and otherwise little-known names for body parts actually crop up every now and then on the HH Twitter feed:
…but what’s often just as interesting as finding out that names like these exist, is finding out where they come from.
Some anatomical terms derive from the function of the body part in question: so the jejunum, the second part of the small intestine, takes its name from a Latin word meaning “fasting” because early anatomists were so frequently surprised to find the jejunum empty of food in their dissections.
The name duodenum, meanwhile, belongs on a list of purely descriptive terms: it literally means “twelve finger-breadths”, which those aforementioned early anatomists (when they weren’t busy being surprised by how empty the small intestine was) reckoned was its approximate length. Likewise nostril literally means “nose hole”. Pancreas means “all flesh” (probably because of its fleshy appearance). And cornea literally means “horny” (in the sense that it has a horn-like texture, before you get any other ideas).
A lot of anatomical names, however, are metaphorical—seemingly, body parts have long been given names referring to what they resemble, not what they are or how they work. So thyroid literally means “shield-shaped”. Muscle derives from the Latin word for “mouse”, as those early anatomists (when they weren’t busy measuring your duodenum or finding your jejunum empty) reckoned they looked like mice scurrying around underneath the skin.
Your tibia takes its name from a Latin word for a pipe or flute, while the bone alongside it, the fibula, takes its name from a Latin word for the clasp or buckle, like that of a safety pin or a brooch. The coccyx at the base of the spine is so called because of its resemblance to the bill of a cuckoo, the Greek name for which was kokkyx.
The acetabulum is the indentation that the top of the thigh bone sits inside—it takes its name from the Latin word for a vinegar saucer used in Roman banquets. And the sacrum bone in your pelvis is so-called because it was the joint of an animal once used in sacrificial offerings.
The medical name for your collar bone, clavicle, derives from a Latin name meaning “little key”. Your mandible takes its name from a Latin word essentially meaning “chewer”. Your cheekbone, or zygoma, takes its name from the Greek word for a yoke used to link cattle together. Likewise the name of the vomer bone—which helps form the division between your nostrils—comes from the Latin for “ploughshare”. And the phalanges in your fingers are so-called because they’re arranged in neat sets or rows, like troops in a military phalanx.
But the best of all the anatomical etymologies on offer probably has to be the one we tweeted just this week: