Ankle comes from the Latin angulus (little corner or angle; hook-like) for the bend between the foot and the leg.

Angulus may also be the source for the Latin word angeion, small blood vessel, perhaps in reference to the frequent branching of such. Angeion gives us the combining form angio-, blood vessel, as in angiogram, angiogenesis, and angiotensin.

Non-anatomical tidbits: another word derived from angulus is Angul, the name given to the hook-shaped bit of land in what is now the Netherlands. From this area came the Angles, who along with the Saxons and Jutes, formed the Anglo-Saxons, the people who inhabited the land now called England in the 500 years prior to the Norman invasion of 1066.

An angler, one who fishes (with hooks), is also derived from angulus.

Picasso, Foot, 1894, Charcoal and crayon on paper, Museu Picasso, Barcelona, Spain.

Bile comes from the Latin word for bile, bilis.

The Greek word for bile is cholé and is an oft used combining form: a cholecystectomy is the removal of the gall bladder, literally, "removal of the bile bag" (cyst is derived from the Greek kystis, bag or pouch). Cholecystokinin (CCK) is a hormone that stimulates gall bladder contractions, among other functions (-kinin comes from the Greek kinein, to move or stimulate).

To the ancient Greeks and Romans and other believers in the "four humors", melancholy, from melos (Greek for black) and cholé, was thought caused by an excess of "black bile". The word choleric, meaning easily angered or annoyed, stems from the notion that excessive "yellow bile" was responsible for one's ill-temper. Bile, in its non-physiological sense, still refers to a choleric disposition (as in "full of bile") and bilious, from bilis, refers to someone who is peevish or, logically enough, ill-humored.

Gall comes from the Anglo-Saxon word for bile, galla; thus the "gall bladder", the organ that stores and concentrates bile.

Dens, a tooth-like process on the axis (the second cervical vertebra). From the Latin word for tooth, dens.

An alternative name for the dens is odontoid process (from the Greek odous, tooth, and -oeides, shaped). The term is no longer recognized by the Terminologia Anatomica, but is still firmly entrenched in the anatomical lexicon.

Other words related to dens: dentist, dentate (having a toothed or serrated edge), trident (a three-pronged, or toothed, spear), dandelion (from the French dent de lion, "tooth of the lion", referring to the dentated edge of the plant's leaves), and dentine (also dentin), the bone-like tissue that makes up the bulk of the tooth.

Anterior view of the axis. The oval facet visible on the dens articulates with the anterior arch of the atlas. wheelessonline.com

Medulla, Latin for marrow. Because of its derivation from the Latin medius, middle or core, medulla often implies a deep region within a structure, such as the renal medulla or the medulla of the adrenal gland.

Medulla was the word Vesalius used for the spinal cord, inspired perhaps by the name the Greeks favored: myelos rachites, "marrow of the spine". Indeed, the soft neural tissue of the spinal cord within the vertebral canal of the spinal column does remind one of marrow present in the hollow shaft of a long bone (in the space appropriately called the medullary cavity).

"Marrow" still appears in many English dictionaries as an alternative name for the spinal cord, though this definition has been long since discarded by anatomists.

In spite of being part of the brain, it is the spinal cord that's referred to in medulla oblongata. The term was first used by the German anatomist Lorenz Heister in 1740 and it's not clear why: its meaning does not make a lot of sense ("oblong-shaped spinal cord" or as some translate it, "rather long spinal cord") and there had been a reasonable term in use earlier, the medulla prolongata, which does make sense ("spinal cord extension"). Nonetheless, medulla oblongata became established while medulla prolongata disappeared.

Heister's original use of the term was for the entire brain stem. In 1750, the Swiss anatomist Albrecht von Haller restricted the use to its present meaning: the thumb-size segment of brain stem continuous with the spinal cord. (Haller, considered the father of modern physiology by many medical historians, named the Graafian follicle in honor of Dutch anatomist and poet Reinier De Graaf who discovered the ovarian follicles (but thought they were eggs)

Albrecht von Haller (1708-1777) www.ilmyco.gen.chicago.il.us

Chiasma, a "crossing", from the Greek letter for X, chi (pronounced "ki", rhyming with "sky").

The term was first used by first century Romans for the X-shaped crossing of the optic nerves just anterior to the pituitary. For some reason the word fell out of favor with subsequent generations of anatomists; not until the late 1500's was it revived, reentering the anatomical lexicon for a permanent stay (although "optic chiasm" is now preferred over "optic chiasma" by about a 4 to 1 ratio; both terms are recognized by the Terminologia Anatomica.)

True to its derivation, chiasma is pronounced with a hard ch, as in "chronicle".

Chi

From the archives:

Mitral is derived from the Latin mitra, girdle or turban, which gave rise to mitre, the ceremonial head-dress first worn by Roman Catholic bishops. Subsequently the hat was adopted by bishops of the Anglican, Episcopal, and some of the Christian orthodox churches.

A 15th century bishops' mitre on the left, a present-day mitre on the right, and in the middle, a 16th century-style mitre from the time of Vesalius. Adapted from the Catholic Encyclopedia www.newadvent.org		21st century mitre. murphyrobes.com

The mitral valve of the heart, positioned between the left atrium and left ventricle, was so named by Vesalius in the 16th century because its two parallel cusps (flaps) resemble of the paired, pointed "horns" or cornua of an (upside-down) bishop's mitre. Thomas Henry Huxley, "Darwin's bulldog" and the person who coined "agnostic", would give his students this mnemonic to remind them the valve was on the left: "a bishop is never in the right."

The mitral valve is also known as the bicuspid valve or the left atrioventricular (AV) valve. The Terminologia Anatomica no longer lists bicuspid.

Upside down view of the mitral valve showing its mitre-like appearance. From top to bottom, note the papillary muscles, the chordae tenidneae, and two cusps of the valve www.lionden.com

From the archives:

Mental, in anatomy, is an adjective meaning "related to the chin". It comes from the Latin word for chin, mentum.

Its use is seen in the mentalis, a muscle covering the tip of the chin, and the mental foramen, a small passageway found near the chin on each side of the mandible through which the mental artery, vein, and nerve pass.

Across all cultures it is common for people to touch their their chins as they ponder, but mental as in "mental images" comes from mens, Latin for mind, and not from mentum. However, as mentum is so closely linked to mens through our behavior, some etymologists believe (albeit without evidence) that both words are somehow etymologically related.

The Thinker by Auguste Rodin: engaged
in two types of mental activity.

The Anatomy Word of the Day is taking a Thanksgiving break. The next few days' worth of entries are from the archives.

Fornix (plural, fornices), comes directly from the Latin word for a vault, i.e., a small room with an arched ceiling. Often the term was by the Romans in specific reference to rooms occupied by slaves or the poor. Street prostitutes were known to provide their services in fornices; hence the word "fornication".

The use of fornix in anatomy includes:

• The left and right fornices of the brain's limbic system, formed by white matter tracts that arch over the diencephalon,
  
• The vaginal fornix, the vaulted space in the vagina that surrounds the cervix of the uterus
• The gastric fornix, a term used in radiology for the internal arch of the fundus.
  

A series of fornices in Roman ruins, Gaeta, Italy, with the front walls and doors long gone. Modifed from A Dictionary of Roman Antiquities, by Antony Rich, Appelton, 1874.

Afferent: moving towards something; used in reference to blood, lymph, or nerve impulses. Derived from the Latin afferre, ‘bring towards’.

Afferent arterioles in the kidney convey blood towards the glomerular capillaries. Afferent neurons carry impulses towards the central nervous system (and thus are always sensory in nature). Afferent lymphatic vessels carry lymph into lymph nodes.

Afferent arterioles ('a') carrying blood to glomerular capillaries; arrow indicates direction of flow. (Adpated from bicmra.usuhs.mil/)

The opposite of afferent is efferent (from the Latin efferre, to carry off) which refers to movement away from a reference point. Efferent arterioles carry blood out of the glomerular capillaries. Efferent neurons carry impulses from the central nervous system (and thus are motor). Efferent lymphatic vessels carry lymph out of lymph nodes.

An easy mnemonic: Afferent Arrives, Efferent Exits.

Fossa, from the Latin fossa, ditch or trench.

Anatomically, a fossa is a depression or hollow. It is the most commonly used descriptive term in anatomy, seen in 64 different structures in the Terminologia Anatomica; the most frequently cited structure (on the Internet at least) is the iliac fossa, followed by the popliteal fossa, fossa ovalis, mandibular fossa, and olecranon fossa.

A word that shares Latin roots with fossa is fossil, coming from the Latin fossalis, dug up. Fossa and fossil ultimately stem from the Latin verb fodera, to dig.

Pancreas, from the Greek pan, all, and kreas, flesh.

The original use of the term, dating to at least the time of Homer in the 8th century BC, was for any edible meat or meat-like substance. Herophilus, the 3rd century BC Greek physician out of Alexandria, was the first to use the word for the organ, naming it for its meaty appearance.

"Sweetbread" is the traditional dinner-table term for either the pancreas or thymus gland taken from calves or lambs; the culinary pancreas has also been called stomach sweetbread. Today it is typical for only the thymus to end up in a recipe while the pancreas is more likely to be sold to pharmaceutical firms.

Another word derived from kreas is creatine, the energy-storage molecule first found in skeletal muscle.

Fimbria, direct from the Latin fîmbria, the ornamental fringe on the borders of clothing, cloth napkins, etc.

The fringe on the border of the uterine tubules were first called fimbria in the 17th century by the Dutch anatomist Reinier De Graaf (the man who coined "ovary" and discovered that ovaries produce eggs, and in whose honor the Graafian follicle was named).

Julius Caesar favored fimbria on the sleeves of his tunics (interesting as this was considered an exclusively feminine affectation by both the Greeks and Romans).

An engraving of a Roman dinner napkin with fimbria; from a painting found in Pompei. From A Dictionary of Roman Antiquities, by Antony Rich, Appelton, 1874.

Lumen, straight from the Latin for light, lumen. The Romans also used the term for the aperture of windows, particularly round ones, and it once was the name given to the pupil of the eye.

Its anatomical usage now is reserved for the space inside a tube, e.g. an arterial lumen, a definition probably stemming from a tube's round opening when seen in cross section, or perhaps from the light seen through a tube if opened on both ends.

In physics, a lumen is a unit of brightness. A 100-watt incandescent light bulb generates about 1600 lumens.

Other words from lumen include luminary, luminescence, illuminate.

Jejunum, from jenunus, Latin for empty or hungry: This portion of the small intestine, the 3 feet or so between the duodenum and ileum, is typically empty when dissected, perhaps as a result of residual peristalsis in the moments after death or because most will not have eaten in the hours before death.

The original name, given by Galen, was nestis, Greek for fasting. Later the term was translated into Latin as jejunum.

Also derived from jenunus is the word jejune, something insubstantial or devoid of interest, such as the jejune comments of politicians.

Canine, aka the cuspid, the tooth between the lateral incisor and first bicuspid. It gets its name from canis, Latin for dog, which in turn comes from the Greek word for dog, kynos. The Greeks were indeed the first on record to note the tooth's superficial resemblance to the corresponding dog tooth, in particular the relatively long, often sharply pointed cusp.

The upper canines are sometimes called the "eye teeth", perhaps because their roots can extend close to the lower margin of the orbit during their development in the maxillary bones. For reasons unknown, the lower canines have been called the "stomach teeth", a phrase of uncertain origin that has all but disappeared.

Most dentists and dental hygienists freely use both canine and cuspid (perhaps preferring the former since canine would be a more familiar term to the majority of their patients). Among anatomists however the preferred term is cuspid (from the Latin cuspis, point); canine is not listed in the Terminologia Anatomica.

The crown of a developing canine (arrow) in the skull of a child approximately 9 years of age. Photo by C Carpenter

Navicular is derived from the Latin navicula, little boat (the diminutive of navis, boat).

There are two bones in the skeleton commonly called the navicular, one a carpal and the other a tarsal; both are named for their resemblance to little boats. However, the Terminologia Anatomica only recognizes the tarsal as the navicular; the carpal is more properly called the scaphoid (from the Greek skaphe that, like navicula, also means a small boat and from which comes the word skiff).

Other words derived from navis include navigation and navy.

The right navicular of the foot. The concave, proximal surface (the top of the boat) articulates with the head of the talus. Its stern is on the foot's medal aspect. Photo by C. Carpenter.

Modified from www.healthcareers.umn.edu

Dartos, the smooth muscle layer just deep to the skin of the scrotum; from the Greek, dartos, skinned or flayed.

The term was first used by Greek physicians for any anatomical preparation in which the skin had been removed. The first-century Romans, for reasons unclear, began using the term only for the muscle seen after removal of the skin of the scrotum; the name stuck.

When exposed to cold the dartos contracts. The scrotal skin wrinkles, the exposed surface area is reduced, and heat loss is minimized. Thus the muscle helps to regulate the all-important testicular temperature (and working with the spermatic cord's cremaster muscle which contracts to pull the testes towards the warm abdominal wall).

In females, a homologous muscle called the "dartos muliebris" (muliebris is Latin for "womanly") is found beneath the skin of the labia majora and is much less developed than the male counterpart. Its function probably rivals that of male nipples in importance.

Larynx comes directly from the Greek larynx which in turn is from larungao, Greek for scream or bellow. The earliest recorded use of the term was by Aristotle in the 4th century BC.

Commonly known as the voice-box, the larynx houses the vocal folds; it is the only component of the respiratory system located entirely within the neck.

"Larynx" is probably the most misread and thus most mispronounced word in anatomy. The correct pronunciation is "lair-rinks", not the oft-heard "lair-niks". I've had the disconcerting experience of being treated by health professionals who said lair-niks, immediately raising the perhaps unfair but easily avoidable question: What else don't they know?

Anterior view of larynx, trachea and bronchial tree from Andreas Vesalius De Humani Corporis Fabrica, 1543, p.151

Omentum. The earliest recorded use of the word was by the Roman writer Celsus in the first century B.C. who referred specifically to the abdominal structure now called the greater omentum. The term has always been employed in an anatomical sense; there is no other known use.

Its derivation a mystery and Celsus left no clues. It may come from operimentum, Latin for the cloth used as a bed covering in ancient Rome much as the greater omentum covers the small intestine (the lesser omentum encloses the bile ducts and hepatic vessels). Others suggest it comes from opimus, Latin for plump, which would be an allusion to the fatty nature of the omenta. Or the term may come from the Latin omen, given the practice among some of the ancient soothsayers to prophesy using the entrails of sacrificed animals (and employing, as it were, a gut instinct as to what specific omens the visceral mess may signify).

The beer belly in men is due primarily to accumulation of greater omentum fat (with mesentery fat sometimes contributing). In women, abdominal fat is more likely to accumulate subcutaneously.

www.bbc.co.uk

Lens, from the Latin, lens, the lentil bean.

The lens of the eye was so named by the Romans in the 1st century B.C. because of its resemblance to a lentil bean in shape and size.

The diameter of the human lens at birth is about 6 mm. By the time one is in their mid-sixties the lens will typically have reached a maximum diameter of around 9 mm. (The average diameter of a lentil is 6-7 mm.)

Lentils www.all-creatures.org

Malleus, Latin for hammer; the auditory ossicle that articulates with the the incus medially and the tympanic membrane laterally.

As the incus (Latin for anvil) does bear a striking resemblance to anvils going back to ancient Rome, you'd be justified in assuming that the naming of the malleus was inspired by the blacksmith's hammer. Indeed, the bone does have a long handle and a head that articulates with the incus, just as the hammer of a blacksmith should. However, it resembles not the hammer of the smithy but the hammer of the priest, used to stun oxen prior to sacrifice; butchers used it too. This tool was large and heavy, requiring two hands and not an obvious inspiration for the name of one of the smallest bones of the body. However, it had a distinctively round head like that of the ossicle and thus the bone was so designated as the malleus.

The shape of the sacrificial hammer may also explain the rather mysterious naming of the lateral malleolus and medial malleolus, the "little hammers" of the ankle that are so much larger the malleus of the ear. These rounded bony processes were probably given their name because they reminded Vaselius, who first used the term anatomically, of small versions of the large, round head of a malleus.

Other words derived from malleus include mallet and malleable, the latter in reference to metals such as gold that could be molded with hammer blows.

The malleus; adapted from Anatomy of the Human Body; Henry Gray. 1918

A sacrificial malleus from ancient Rome, from An Illustrated Companion to the Latin Dictionary and Greek Lexicon, Anthony Rich. 1849