This week’s theme-title is a pun. We’ll be talking about words related to parts of the face.
sclera – the white of the eyeball
– Jacqueline Sheehan, Lost & Found
I mention this last because it has a much more interesting figurative use, to mean “rigidity, excessive resistance to change”. It’s been used to refer to theater (old-fashioned and sclerotic), transportation (the traffic [gets] more sclerotic), and governments (sclerotic tax laws). And here’s a spin-off coined (apparently by German economist Herbert Giersch) in the 1980s:
– New York Times, April 9, 1986
Anyone who has ever dissected an eyeball knows that the sclera is appropriately named. I used to teach a lab in which we dissected bovine eyes. It's like cutting open a racquetball. I would toss a whole one on the floor and challenge one of the students to stand on it. They can usually support at least 150 lbs before rupturing.
Wow, my anatomy teacher never did that. How interesting!
Just think how many things get blown in your eye every day.
My friend in Medical School reported on an incident when he and his classmates were paired off to do dissections, two students and a ... cadaver ... per cubicle. Concentrating that day on the Genito-urinary systems. From one of the cubicles came the voice of a female student saying, "I always thought it had a bone in it."
Here’s a famous sinciput:
sinciput – the forehead (also, the upper half of the skull)
[From Latin, meaning ‘semi-head’. A truly obscure word for the same thing is bregma. Compare occiput – the back of the skull.]
– Edgar Allen Poe, The Business Man (excepted)
spalpeen – Irish dialect: rascal; scamp
nares – nostrils
Illustrated by two quotes with unusual perspectives. In the first, a fish insults a swan. In the second, we consider how the Invisible Man’s innards work.
. . .“Nonsense,” said the swan snappily, putting its head into the water rand giving them a frown with its black nares. “Swans like to rest in this position, and you can keep your keep your fishy sympathy to yourself, so there.” It continued to glare at them from up above, … until they were out of sight.
– T. H. White, The Once and Future King
After he had done eating, … the Invisible Man demanded a cigar. … It was strange to see him smoking; his mouth, and throat, pharynx and nares, became visible as a sort of whirling smoke cast.
– H.G. Wells, The Invisible Man
edentate – toothless
[also refers to certain mammals, such as armadillos, that are toothless or nearly so]
– Kurt Vonnegut, Galápagos
Flashback induced by reading "edentate," bringing to mind actuarial studies from early in my career:
"...The difference in 7-year mortality between edentulous subjects and those with ≥20 teeth was evident among men in cohorts II and III and in both genders in ..."
I'm curious: how did the edentulous subjects fare? I'm guessing badly.
Alas, neveu, you have the instincts of an actuary.
That need prove no impediment to social success. I for example have kept those same instincts in check for many years now...
As to the toothless - yes, the edentulous fare worse over time. Factors include correlation of poor health with tooth loss, as well as difficulty in getting proper nutrition.
The ancients knew a fair bit of actuarial science. Prince Hal, for example, notes the grave gapes three times as wide for Falstaff for his weight.
The site was down when I tried to post this last night.
It's noisy, and to block out the noise you stick your finger in your ear, palm forward. Your fingerpad presses against a stiff flap of cartilage. Who'd have thought that it had a name? This is not an easy word to work into a conversation!
tragus – the bump of cartilage in front of the ear-hole
[from Greek for "male goat", supposedly so named for the tuft of hair which grows there]
– Liam Durcan, Garcia's Heart
Tragus also gives us the tragos-oide or goat-song, described in Online Etymological Dictionary as: "a dramatic poem or play in formal language and having an unhappy resolution." Tragedy.
Dictionaries conflict on today’s word. AHD has it as a horse-word (a sudden, violent check of a horse, by drawing the reins suddenly), but to Merriam Webster it pertains to the eyes. Neither mentions the other’s sense. For our theme, we focus on the eyes.
saccade – a brief, rapid eye-movement from one position of rest to another, either voluntary (as in reading) or involuntary
– Adam Davies, Goodbye Lemon (ellipses omitted)
Beep! A new [email] message had just arrived. The sender’s address was -- My God … He opened the message, and his eyes flew all over it in mad saccades, trying to absorb it as a gestalt. And then, his pulse racing, he re-read it carefully, from top to bottom.
– Robert J. Sawyer, Rollback
– Leo L. Sullivan, Life
Does anyone know the difference between this and nystagmus? I would define jerky eye movements, as in this definition, as nystagmus, and I haven't heard of saccade before. Here is an online definition for nystagmus: " Involuntary movements of the eyes, often noted as shaky or wiggly movement." Perhaps the the difference is that saccade can be voluntary; nystagmus is always abnormal.
Not exactly. Everyone with normal vision is saccading once or twice every second; you cannot will them to cease completely. If they are suppressed (mechanically or pharmacologically) you "grey out" and only see patches of the scene or parts where things are moving. Your eye needs to be constantly moving in order to properly see.
The eye movements in nystagmus may or may not be saccades (that is, driven by the saccadic control system of the brain) depending on the type of nystagmus, but voluntary nystagmus, the ability to rapidly vibrate one's eyes side-to-side at will (which I can do, by the way), appears to be regular saccades rapidly cycled with little or no refractory period between them. It used to freak kids out in grade school.
edentulous is now the more usual form. And, thanks to dental hygiene but more especially (involuntary) fluoride intake, the incidence has declined in the last 20-30 years.
Saccades refer to any sudden movement of the eyeballs whether conscious or unconscious, normal or abnormal.
Nystagmus is generally an abnormal (pathological) movement of the eyeballs, but has many different and complex patterns depending on direction of primary gaze, speed and type of movement, etc. It can even be dysconjugate—affecting one eye more than the other. It can be congenital, or, caused by a large number of diseases in various sites in the brain, and also induced by drugs, including alcohol. Too big a topic for a blog.
This is not correct, at least not among people who publish about these things. Saccades are specific, high-velocity, time-optimized eye movements that redirect fixation. They can be distinguished by their angle/maximum velocity profile from other kinds of eye movements, and they are produced by a particular control center in the brain.
An interesting word, first coined (in the eye movement sense) by Louis Émile Javal, a French ophthalmologist, in the late 19th century, from an equestrian term, from French saquer 'to jerk, pull abruptly' (< VL verb *saccare, supposedly related to sac 'sack, bag', but I couldn't track that down). (Extra: Javal became totally blind by 1900 and was an Esperanto enthusiast, being a friend of L L Zamenhof, who was also an eye doctor.)
—Ceci n'est pas un seing.
Your 19th-century dating is interesting z. OED has 1953 and MW has 1938 (each for the eye-moment sense). But perhaps it was 19th century in French, and didn't come into English until later. Do you have any more details of the 19th-century usage?
Here's an example of the equestrian meaning from an early 19th century dictionary (1835).
It seems to have been known as a medical term, as this antebellum (1845) article shows, and, with regards to respiration, in this postbellum one (1868).
And, erotic argot, too: from an 1889 dictionary of slang (from Rabelais "Elle aura par Dieu la saccade, puisqu'il y a moines autour").
Finally, here's a 1922 citation for saccadic. (More searches on Google books or scholar may help.)
—Ceci n'est pas un seing.
This week quite a few readers have written asking me, “Are you going to do my favorite body-word?” Every one of them had the same favorite, and it’s one of my favorites too. How curious; I wonder why so many of us like it.
philtrum – the vertical groove from the base of the nose to the upper lip
[from Greek philein "to love; to kiss"]
– Diane Ackerman, The Zookeeper's Wife
A friend of ours is a paramedic. When one of her patients is about to faint, she pinches the patient's philtrum – the fleshy part between the upper lip and nose. That prevents the faint from happening.
– Joan Wilen and Lydia Wilen, More Chicken Soup & Other Folk Remedies
I seem to recall learning somewhere that it often presents in persons undergoing the last stages of starvation.
What types of people publish about saccades? Is it medical people? I've not heard the term before at all.
I find it interesting that the OED Online cites 1953 for saccade, but 1916 for saccadic.
The Moving Tablet of the Eye: The Origins of Modern Eye Movement, by Nicholas Wade and Benjamin W. Tatler (Oxford University Press, 2005) says that Javal's mention of saccades in his 1879 book were in reference to work done by Lamare (page 134).
Roger P. G. Van Gompel says essentially the same thing in Eye Movements: A Window on Mind and Brain (Elsevier 2007, page 49; E-book)
People like me! Well, not me, exactly, but my dissertation adviser made a career of it (see esp. #168). People who study vision, or eye movements, or neurology, or ophthalmology. There's a whole neurological system that drives these eye movements, and we would like to understand how it works. And they are crucial for our visual system to work properly, so we'd like to understand that business, too.
Neveu, your description is correct, but is entirely consistent with my deliberately non-technical one liner! There are many detailed publications and explanations, but for anyone curious enough to be interested in the technicalities, a very brief summary might be:
The major conjugate eye movement systems are saccades and pursuit. The saccadic system controls rapid eye movement and maintains fixation (foveation) on the object of regard. Horizontal saccades are controlled by contralateral frontal eye fields in the frontal lobe. The right frontal lobe controls saccades to the left, and the left frontal lobe controls horizontal saccades to the right.
The pursuit system controls smooth tracking to follow slow-moving objects. The pursuit movements are controlled by the parietal lobe on the same side (ie, right pursuit is driven by the right parietal lobe, and left pursuit is driven by the left parietal lobe). Most voluntary eye movements are a combination of saccade and pursuit eye movements.
Saccades can be tested by asking a person to move his or her eyes in a particular direction. Separating saccades from smooth pursuit may be clinically important. Smooth pursuit may be irregular in brainstem-cerebellar disease, and catch-up saccades may be required. In certain syndromes, upgaze saccades may be affected more than upward smooth pursuit early in the disease. In patients with small pontine strokes involving purely the paramedian pontine reticular formation (PPRF), saccades may be affected and smooth pursuit relatively preserved, because the fibers of the latter eye-movement system do not synapse in the PPRF.
Nystagmus is defined as a periodic rhythmic ocular oscillation of the eyes. The oscillations may be sinusoidal and of approximately equal amplitude and velocity (pendular nystagmus) or, more commonly, with a slow initiating phase and a fast corrective phase (jerk nystagmus).
Nystagmus may be unilateral or bilateral, but, when the nystagmus appears unilateral, it is more often asymmetrical rather than truly unilateral. Nystagmus may be conjugate or disconjugate (dissociated). It may be horizontal, vertical, torsional (rotary), or any combination of these movements superimposed upon each other.
The detailed analysis of these eye movements is invaluable in location and diagnosis of diseases of the brain and brainstem.
Pearce, we send you sincere expressions of heartfelt gratitude. Now, thanks to you and Neveu, we know precisely what to tell our grandchildren when they ask about saccades and nystagmus.
~~~~~ jerryThis message has been edited. Last edited by: jerry thomas,
I didn't want people to go away thinking that any old jerky eye movement is a saccade, which was one way to interpret your non-technical one liner.
Apparently I just didn't study eyes enough, as clearly saccode is a medical term.
Pearce had said that "generally" nystagmus is pathologic (I had thought it always was), though "saccades" seem to be more general, including both pathologic and normal movements. Yet, neveu says that any old jerky movement isn't a saccade. So that conclusion about saccades being more general might not be correct; is it? Is any old jerky movement nystagmus then?
Not always. Gazing at the scenery from the side window a moving train can induce optokinetic nystagmus, and there's also voluntary nystagmus.
Maybe saccade used to include pathologic movements, but now it almost exclusively refers to normal eye movements. The presence of saccades can be pathological, but they are normal saccades. For example, schizophrenics tend track moving objects using saccadic eye movements rather than smooth pursuit movements, jumping ahead to where the object will be, briefly fixating then jumping again, instead of smoothly following the target like a normal subject.
No. Saccade is more specific; nystagmus is more general.
I'd say any old "periodic rhythmic ocular oscillation" probably counts.This message has been edited. Last edited by: neveu,
Showing off one's professional knowledge is not generally a laugh, nor useful intelligence to those not in need. I really don't think it apt to indulge in such a specialised and technical physiological/neurological topic in this setting, but let's be correct.
in nystagmus,which is usually pathological, the primary eye movement is an oscillation; but it swings back rapidly, and this is called a corrective saccade. So it's wrong to say that saccades almost exclusively refer to normal eye movements, though saccades are an element in normal eye movements, especially fixation et.c etc.
I shall say no more on this matter.
nevau, pearce, this discussion is hard for me to follow, but it would be no surprise if the definition I gave isn’t quite right. That's understandable when a term specific-to-a-field is defined by someone not personally familiar with that field. For example, I’ve found that OED not-infrequently err when defining terms from field (e.g., basketball) that I happen to know well.
Here are OED’s definitions of the terms you’re talking about. If (as I think you’re saying) those definitions are not quite right, could you please provide a corrected text, plus a brief explanation of the change of the sort a layman could follow? I’ll pass it on to the folks at OED.
saccade – A brief, rapid movement of the eye from one position of rest to another, whether voluntary (as in reading) or involuntary (as when a point is fixated).
nynstagmus – Involuntary, rapid, oscillating movement of the eyeballs (most commonly from side to side); an instance or type of this.
Apparently this is a matter of opinion. I tend to prefer discussions in which at least one person actually knows what they are talking about. Kalleh asked, I answered. Sorry.
Let's be correct. The primary eye movement is a drift, and that the combination of drift and saccade produce the oscillation.
As I said, saccades can be components of pathological movements. The corrective saccade in nystagmus is a normal fixation saccade, correcting for a drift off the fixation point. The saccade is not the problem, the drift is. The saccade is the solution. Together they create a pathological condition called nystagmus. They are perfectly normal saccades as can be seen by their position on the main sequence.
Moreover, when I said "Maybe saccade used to include pathologic movements, but now it almost exclusively refers to normal eye movements" I meant the following: if you search for "saccade" in Google Scholar, it will bring up hundreds of papers about saccades. These papers are not about any old jerky eye movements, nor are they about some kind of pathology, they are specifically about a particular kind of ubiquitous time-optimal refixation movement, with a particular control signal, coming from a particular part of the brain. Med schools may have taught something different before about 1965, but that's what the word means today.
I have no problem with either definition.