9/28/07

Clitoris is derived from the Greek word for clitoris, kleitoris, which in turn comes from kleio (to close, as with a door or latch), perhaps in reference to those portions of the labia minora that enclose the clitoris, or to the clitoris as a metaphorical gateway to the vagina.

Some have suggested that clitoris may be derived from the Greek verb for tickle, kleitorizein (the German word for clitoris is der Kitzler, the tickler). However,
kleitorizein may be dervied from Kitzler (kleitorizein also means "to touch the clitoris").

Gabriele Falloppio (of Fallopian tube fame) was the first to systematically describe the external anatomy of the clitoris back in the 16th century.

The clitoris is rarely represented in its entirely in textbook diagrams and anatomical models. The average length of the adult clitoris from the visible glans to the embedded ends of the crura (which attach to the bones of the pelvic girdle) is about 4".

The image “http://www.luckymojo.com/clitorisfrontview.gif” cannot be displayed, because it contains errors.
The clitoris surrounding the penis during intercourse.
The outer layers of the woman's skin and fat are not shown and the
penis is represented
as a feature-less cross-section. The ascending
portion of the clitoral shaft can be seen above the glans (the glans is the
portion usually visible). The shaft bends posteriorly at its apex
and divides into the two "legs" (crura ) which encircle the vaginal opening
and the penis.
Drawing by Robert Latou Dickinson, in Human Sex Anatomy, 1949.




Lateral view of the clitoris
This diagram is from a US college website, but I lost the link.
If anyone knows, please leave a comment.

9/27/07

Ileum, from the Greek word for twisted, elios. Its a matter of conjecture why only the last 2/3s of the small intestine should be called "twisted" (in the sense of meadering) even though the initial 1/3, the jejunum, is worthy of the distinction as well.

It has been suggested that the word may stem from the use of elios by ancient Greeks for pathologies such as torsion, obstructions, or paralysis that are somewhat more common in the more distal portions of the small intestine .

Ileus as a term for intestinal paralysis was first used by Hippocrates in the 5th century B.C.

The ilium of the pelvic girdle didn't make its appearance in anatomy until Vesalius named it in the 16th century. The ancient Romans used the word for the soft areas of the abdomen, such as the flank or belly, and not the bone; in fact it may have come from ilia, the Latin word for soft (ilia was used by the Greeks for the female external genitalia). Others have suggested it comes from os ilei, "the bone the ileum lies against".

9/25/07

Coronary, from the Latin corona, garland, wreath, or crown. Corona is also Latin for boundary.

When viewed from above, it can be seen that the right and left coronary arteries (more specifically, the right coronary and circumflex branch of the the left coronary) encircle the heart like a crown.

The coronal suture of the skull, linking the frontal bone to the parietals, is arranged vertically instead of encircling the cranium. It is very roughly reminiscent of the style favored by Roman emperors for the wearing of a garland, or corona , i.e., high on the forehead, and this has been suggested as the inspiration of suture's name.

However, the another Latin meaning of corona is a boundary such as the edge of a field and, perhaps from this definition, the anterior edge of the hair on the head. Especially in one with a receding hairline, the position of the coronal suture and the pattern of hair growth closely match, and perhaps from this relationship came the name of the suture Others suggest the term simply is in reference to the edge of the frontal bone.

In any event, corona in an anatomical sense does not appear in any extant Roman writings. It first makes its appearance around the 10th century in Latin translations of Arabic anatomical texts.

A coronal section initially referred to a cut made along the coronal suture. The term has since become generalized to mean any such cut that separates anterior and posterior regions.

Some non-anatomic words derived from the Latin corona include coronation and coroner (the original definition of the latter word was "an officer appointed by the crown").

http://aycu11.webshots.com/image/11210/2006300190770596364_rs.jpghttp://www.notablebiographies.com/images/uewb_02_img0134.jpg
A transverse section through a plane containing the heart valves. The circumflex artery curves around the mitral valve on the left, and on the opposite side, the right coronary artery curves around the tricuspid, with both vessels almost touching posteriorly and thus completing the crown.
radiologynotes.servehttp.com
Julius Caesar wearing a corona.
Courtesy of the
Library of Congress


Abducens: cranial nerve number six; carries somatic motor impulses to the lateral rectus muscle on the lateral side of the eyeball. Also known as the abducent nerve.

From the Latin ab (away) and ducere (to lead). Named for the consequences of its action: when the nerve stimulates the lateral rectus to contract, the eyeball is abducted (i.e., turned away from the midline).

The lateral rectus muscle was once known musculus amatorius ("love muscle") because of its action in producing the alluring sidelong glances of lovers (though the contralateral medial rectus muscle is also used in this look, it's the eye that's moving laterally that gets all the attention.)

"ASKANCE"
Original Oil by Don Huebner
www.artbydonhuebner.com

9/24/07

Androgen is from the Greek andros (a man), and genao (I produce). The androgens include a number of hormones, testosterone being the most predominant.

The dramatic role that androgens play in male sexual development can be deduced by observing those with complete androgen insensitivity syndrome (CAIS). These individuals have the XY genotype and thus would be males were it not for the fact that they lack all androgen receptors on their cells. Consequently, in the absence of androgen stimulation, those with CAIS are females, externally appearing as normal girls or women and typically choosing a female gender identity. Internally they have no uterus, fallopian tubes or ovaries, and have testes in the abdomen.

   
Cindy Stone has complete androgen insensitivity syndrome. She is shown here at age eight and as an adult. Her thoughts about the condition, along with others with disorders of sexual development (DSDs), can be read at www.dsdguidelines.org/htdocs/parents/adults_memories.html

9/21/07

Adipose is derived from adeps, the Latin word for grease, lard, or animal fat (see abdomen). The first recorded English use of adipose was in the mid-18th century. It is not known who coined the term.

Adeps had already entered the English language in the 17th century, meaning fat generally, but also referring specifically to the internal abdominal fat of the hog, usually that of the mesenteries, omentum or renal adipose tissue, that had been removed and purified for use in the preparation of skin ointments.

Other words derived from adeps (from http://www.wordinfo.info):
  • adipocere: A grayish fatty substance generated on or in dead bodies that were buried in moist places or submerged in water. It can persists for centuries (synonyms: grave wax, lipocere).
  • adipescent: Becoming fatty
  • adipophobia: An abnormal fear of being too fat
  • adipate: To feed fat.

"More to Love"
A painting of adipose tissue
by
Odra Noel.
http://www.odranoel.eu/

9/20/07

The carotid artery gets its name from the Greek karos, which means "deep sleep or stupor". The term was already being taught in Roman medical schools early in the first century A.D., and was quite possibly used by the Greeks 300 hundred years earlier as it was Aristotle (384-322 BCE) who first noted that pressure on the both carotid arteries could induce a stupor.

Galen claimed, from the results of his experiments, that carotid pressure did not produce any kind of stupor. However, he probably was basing his observations on the response of ruminants which have a very effective collateral blood supply to the brain through a number of vertebral vessels; consequently they don't show a loss of consciousness even with prolonged pressure applied to the carotids.

In humans, the "blood choke" (carotid restraint) in which both carotids are compressed typically leads to unconsciousness in around 10 seconds. Once pressure is removed, consciousness is regained in 10-20 seconds


Carotid restraint
www.answers.com

9/19/07

Fontanelle (also fontanel), from fontanella, from the Italian word for little spring or fountain: any of the six soft, membranous regions in the the cranium of an infant or fetus where bone tissue formation has yet to take place. The word was coined in Italy in the 13th century.

The term originally referred only to the anterior fontanelle, located on the top of the skull between the parietal bones. It is the largest and the last fontanelle to disappear, usually by the 24th month; in casual usage, it is referred to as the soft spot.

The fontanelles seem unrelated to either fountains or springs and three suggestions, all in reference to the anterior fontaenlle, have been offered to explain the link. In order of decreasing plausibility:

  • The natural spring explanation: the ground at the site of a spring often has a slight hollow or indentation associated with it, as may the anterior fontanelle.
  • The surgical explanation: in the 13th century a blood-letting procedure was developed for the treatment of brain and eye disorders in newborns. The technique involved creating a small opening in the anterior fontanelle so that blood, carrying supposed poisons, could flow out and effect a cure. The welling blood could have reminded one of a fountain.v
  • The pulsation explanation: a pulse can be felt in the anterior fontanelle, perhaps reminding one of the pulsating flow typically seen in fountains with a vertical water spout. Such fountains would have been a common site in 13th century Italy.

The anterior fontanelle in a newborn
commons.wikimedia.org

9/18/07

Biceps comes from the Latin words bis (twice) and caput (head). The biceps brachii is a muscle with two "heads" (or origins).

Biceps is both singular and plural, although about a quarter the usage on the Internet is in the pseudo-singular form of "bicep". (To be strictly correct, the plural of biceps is bicipites, used only by those who wish to flaunt their learning to the of point annoyance).

The biceps brachii was named in 1734 by the German anatomist Bernhard Weiss (who went by the Latinized name of Albinus).



Albinus (1697-1770)
clendening.kumc.edu

9/17/07

Abdomen, directly from the Latin abdomen, belly. Obscure origins, but most probably came from either of the latin words abdere (conceal) or adeps (fat)

The term was originally applied to the bellies of pregnant pigs, whose milk-laden mammary glands were eaten as delicacies in ancient Greece. Around 60 B.C., Cicero and the Greek comedy writers began using the word as a humorous insult to pot-bellied men. It was the Greek philosopher Pliny the Elder (23-79 A.D.) who first used the term in the anatomical sense familiar today.

Related usage: rectus abdominis. If well-defined, the rectus abdominis is colloquially called a "six-pack." (Note: often misspelled as “rectus abdominus”; a mnemonic for the correct spelling: i have a six-pack, u don't)


Pliny the Elder
www.crystalinks.com

9/13/07

Obturator comes from the Latin obturare, to close up. The obturator foramen of the os coxa, completely covered by a membrane, was named by the great French surgeon Ambroise Paré in 1550,

The obturator nerve is the only nerve with the name of a foramen that does not also pass through said foramen. It has been suggested the nerve was so-called because it supplies the adductor muscles of the thigh and thus is required to close the legs.

Also derived from obturare: obstruct.

The image “http://ar.utmb.edu/areas/informresources/collections/blocker/portraits/Images/pare.jpg” cannot be displayed, because it contains errors.
Ambroise Pare, 1510-1590
From the Truman G. Blocker History of Medicine Collection, University of Texas

9/12/07

Lymph, from the Latin lympha for "clear spring water". The Latin term can be traced back to the Greek Nymphe (with "L" replacing the "N" for reasons unknown). Nymphe were Greek goddesses of things pastoral, including pristine lakes and springs.

Greek anatomists such as Aristotle and Herophilus noted the existence of what are now called lymphatic vessels, but considered them simply as veins that carried water. Galen said these vessels didn't exist and, given his inexplicable power, such was the dogma for over 1400 years.

Spurred on with the discovery of lacteals by Gaspara Aselli in 1622, the lymphatic system was finally described by a number of anatomists during the mid to late 1600s. Thomas Bartholin, around 1660, was the first to use the term vasa lymphatic (lymphatic vessels), in reference to the watery fluid within (Bartholin's grandson, Kaspar, was the first to describe the greater vestibular glands of the female reproductive system, the erstwhile Barthonlin's glands).

In spite of the successes in illuminating its anatomy, it wasn't until the 1820s that the lymphatic system was understood not to be the general route of absorption, through the lacteals, of food and water.

The image “http://upload.wikimedia.org/wikipedia/commons/f/f4/Thomas_bartholin.jpg” cannot be displayed, because it contains errors.
Thomas Bartholin, 1616-1680
Public domain image

9/11/07

Hymen comes from the Greek hyalos, membrane. The Greeks used the term for any type of anatomical membrane, including the peritoneum, pericardium, and meninges.

Vesalius, in the 16th century, was the first to use hymen specifically for the membrane of the vaginal orifice, perhaps inspired by the name of the Greek god of marriage, Hymen.

http://www.p-synd.com/rennie01sm.jpg
Cupid Rekindling the Torch of Hymen. A statue by the Scottish sculptor George Rennie (1802-1860); Victoria and Albert Museum, London.

9/10/07

Appendix comes from the Latin appendere, meaning to "hang from". The most familiar appendix in the body is the vermiform ("worm-like") appendix which is attached to the the cecum of the large intestine. It contains lymphatic tissue and thus plays a role in immune function, albeit a very minor one.

The other appendices recognized by the Terminologia Anatomica (and often not present): the fibrous appendix of the liver, the appendix of the testis (the hydatid of Morgani), and the appendix of the epididymis,
the latter two being remnants of the and müllerian and mesonephric ducts respectively..

In only 30 percent of us does the vermiform appendix actually hang down from the cecum as is typically seen in diagrams and models; in the remaining 70% of the population it runs upward alongside the cecum and ascending colon. As is typical for structures without important functions, is quite variable in structure with lengths that usually vary from ¼ to over nine inches (with one record case of 13 inches). Check out the online Illustrated Encyclopedia of Human Anatomic Variation for additional details.

The image “http://images.livescience.com/images/top10_vestigial_appendix.jpg” cannot be displayed, because it contains errors.
The earliest known drawing of the human appendix ("n"), done by Leonardo De Vinci around 1505. From O'Mally and Saunders 1952, Leonardo da Vinci on the human body

9/9/07

Sternum is a word that can be traced back to a couple of Greek terms for breast: sternon, a poetic designation for the breast of a man (but not that of a woman) and stethos, an anatomical term for either the breast of a man or woman (and from which comes stethoscope).

Galen, in second century Rome, was the first to use sternon in the anatomical sense of breast bone;
the word transformed into sternum sometime after the fall of the Roman empire in the 6th century. However, os pectoris was the preferred Latin term for well over 1500 years, from the time of ancient Rome through the Renaissance, and was used by Vesalius in the Fabrica. Sternum didn't show up in English until the 17th century and os pectoris was still appearing in English medical dictionaries late into the 19th century.

The components of the sternum are rich in sword-related etymologies. See
manubrium for details.

The bone exhibits a little-known sexual dimorphism: in males the body is typically more than twice the length of the manubrium; in females it is usually less than twice the length. It also shows a number of common structural variations.



Variations in sternum structure.
From The Illustrated Encyclopedia of Human Anatomic Variation.
In a 2006 study done in Istanbul, Turkey, X-ray examination of 1000 individuals with otherwise normal sternums showed 4% with suprasternal bones, 4.5% with a foramen in the body, 27% with a xiphoid foramen, and 27% with a bifid xiphoid process.

9/6/07

Axon comes directly from axon, the Greek word for axle or axis.

In 1845, the Swiss physiologist and comparative anatomist Rudolph Albert von Kölliker (1817-1905) provided the first definitive proof that axons were part of the neuron. 51 years later, in 1898, von Kölliker proposed that these fibers, which form the long axis of the neuron and had come to be called "axis-cylinders", be referred to as "axons" instead. Around the same time, some began using axon as an alternative name for the notocord, but as von Kölliker's axon gained in popularity, axon-as-notocord faded from use.
http://clendening.kumc.edu/dc/pc/kolliker.jpg
www.clendening.kumc.edu

9/5/07

Capillary comes from the Latin capillus which means "hair of the head" (caput, head, plus pilus, a hair). In spite of its etymology, an average capillary is a hollow tube about 8 microns in diameter, about 1/10 that of a typical human hair.

Capillaries were first described in 1661 by the renowned Italian anatomist Marcello Malpighi while observing frog lungs under a microscope; Malphghi was one of the first to use the microscope, invented in the Netherlands a generation earlier, for biological observations.

A human adult has over 60,000 miles of capillaries with a total surface area of 600-1000 square meters, an area equal to 2-3 tennis courts

The total volume of the capillaries is around 4-5 liters, the same as the blood volume; obviously, at any given time, a significant number are empty.


Malpighi's original drawing of frog lung capillaries, modified from Fishman and Richards (1964)

9/4/07

Arbor vitae, Latin for "tree of life", is used to describe the branching pattern of white matter seen in sagittal sections of the cerebellum. This is not because the branchings suggest a tree or represent some kind of life-sustaining function in the cerebellum, but rather because of its resemblance to the foliage of the arborvitae, a group of ornamental plants native to East Asia and North America.

The term was coined in the late 17th or early 18th century by Jacob Winslow, the great Danish anatomist. Winslow did much of his work in Paris and presumably encountered in it Parisian gardens. Most likely he saw Thuja occidentalis, or Eastern Arborvitae (often misidentified as cedar), which was the first North American plant introduced into Europe.

The tree was brought back from the new world in 1534 by French explorers who had learned from indigenous people along the St. Lawrence River that a boiled concoction made from its greenery cured scurvy. It was thus named “l’arbor de vie” by the King Francis I and planted in medicinal plant gardens.

Winslow also named the sympathetic chain and was the first to call the ring of pigment surrounding the pupil the "iris".

Thuja occidentalis
www.preservedgardens.com


9/3/07

Cilium was the Latin word used by the ancient Romans for eyelid.

Though the word seemed to die off with the demise of Latin, anatomist in the 17th century started using the term again, not for eyelids however, but for eyelashes.

Meanwhile, also in the 17th century, the Danish biologist Antony van Leeuwenhoek turned his primitive magnifying lenses to pond water and discovered the microscopic world of biology. He was the first to describe, among many other things, bacteria, sperm cells, red blood cells, and protists, and on some of the protists, small hair-like structures.

In the late 18th century the cellular "hairs" came to called "cilia" given their resemblance, under the microscope, to eyelashes.

Supercilium is Latin for eyebrows and the English word "supercilious" (sneering and arrogant) comes from the arched-eyebrow look that often accompanies those who show such traits.

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cnn.com