Archive for November 10, 2012

CLITORAL ANATOMY IN NULLIPAROUS, HEALTHY, PREMENOPAUSAL VOLUNTEERS USING UNENHANCED MAGNETIC RESONANCE IMAGING

 

Figures

Purpose: We determined the magnetic resonance imaging (MRI) characteristics of normal clitoral anatomy.

Materials and Methods: A series of MRI studies of 10 healthy, nulliparous volunteers with no prior surgery and normal pelvic examination was studied and the key characteristics of clitoral anatomy were determined. A range of different magnetic resonance sequences was used without any contrast agent.

Results: The axial plane best revealed the clitoral body and its proximal continuation as the paired crura. The glans was seen more caudal than the body of the clitoris. The bulbs of the clitoris had the same signal as the rest of the clitoris in the axial plane and they related consistently to the other erectile structures. The bulbs, body and crura formed an erectile tissue cluster, namely the clitoris. In turn, the clitoris partially surrounded the urethra and vagina, forming a consistently observed tissue complex. Midline sagittal section revealed the shape of the body, although in this plane the rest of the clitoris was poorly displayed. The coronal plane revealed the relationship between the clitoral body and labia. The axial section cephalad to the clitoral body best revealed the vascular component of the neurovascular bundle to the clitoris. The fat saturation sequence particularly highlighted clitoral anatomy in healthy, premenopausal, nulliparous women.

Conclusions: Normal clitoral anatomy has been clearly demonstrated using non-contrast pelvic MRI.

Keywords: clitoris, magnetic resonance imaging, anatomy, premenopause, parity.

Although there has been some recent progress, advances in understanding male sexual function and dysfunction have not been paralleled by similar advances in female sexual function, even in basic anatomy and physiology. A problem facing researchers in female sexuality is the fact that the clitoris is largely an internal structure relative to the external visibility of the penis. Clitoral anatomy based on cadaveric studies have been limited by the lack of access to younger specimens with most being from elderly, postmenopausal women in whom erectile structures were distorted by the absence of blood flow and by the embalming process.

Suh described detailed imagery of female genital anatomy using magnetic resonance imaging (MRI) with the blood pool contrast medium MS-325. Visualization was poor or absent on T1-weighted images prior to contrast medium use. Two other reports from the same center indicated that this is useful for evaluating female sexual arousal. However, there is no comment on MRI obtained by the fat saturation technique and planes other than the axial plane are not provided. Prior studies also involved women in whom parity status was unknown. We present findings in a series of healthy, premenopausal, nulliparous volunteers and describe clitoral anatomy as seen in each plane using unenhanced MRI. Dissection studies revealed significant age related atrophy, and so we expected that clitoral tissues of premenopausal women would be more easily distinguished with MRI than would tissues from an unselected group of women.

Materials and Methods: An institutional review board approved MRI study was commenced at the University of Michigan, Ann Arbor in 1994. This prospective study involved the MRI evaluation of 240 patients, specifically to evaluate the effects of a first birth. Among these women were a consecutive series of 10 healthy, nulliparous, premenopausal volunteers with no prior surgery and no abnormality on pelvic examination. They underwent several MRI sequences to test which of them best showed the pelvic floor structures. These scans form the basis of this study.

Scanning techniques included T2-weighted fast spin-echo (FSE), T1-weighted spin-echo and proton density FSE with or without fat saturation. A 1.5 Tesla magnet machine was used to create the images. For most scans 0.4 cm section thickness with a 1.0 cm space between sections and a matrix size of 256 × 256 were used. Each scan was first examined to determine the features present in each plane (axial, coronal and sagittal) with each type of scanning. In a few series 1.0 cm sections were used and the sections omitted anatomical detail. For the purpose of clarifying clitoral anatomy only images using 0.4 cm section thickness are shown. All scans were then reexamined to determine the consistency with each of the features identified. The consistent findings are detailed. Structure identification was based on our previous published cadaver studies.

Results: Clitoral anatomy was shown most clearly in the axial plane. The sagittal and coronal planes provided further details and they were complementary. Ultimately all components of the clitoris, crura, corpora, bulbs, glans and its neurovascular bundle could be clearly identified on MRI after the combination of the 3 planes was used. Each plane provided a different representation of the structure.

The clitoris is ventral to the urethra and vagina. Its body projects into the fat of the mons pubis. It is composed of 5 components, namely the paired corpora united in the midline and separated only by a fibrous septum, the bilateral (vestibular) bulbs and the single glans. The glans is a more caudal structure and, therefore, it was seen in more caudal sections. The corpora diverge and follow the pubic rami on each side, where they are called the crura. The clitoris is distinct from the urethra and vagina. The target-like appearance of the urethra is particularly distinct with the urethral wall having a darker gray color than the surrounding clitoris. The bulbs flank the urethra and vagina laterally. This axial section lies directly caudal to the symphysis pubis. The fat in this sequence is the whitest structure, followed by the cavernous tissue of the clitoris, the urethral lumen, the vaginal wall, the urethral wall and finally muscle in decreasing order of intensity. Dorsally the clitoris, urethra and vagina are related to the ischiorectal fat and in the midline they are related to the anal canal. The body of the clitoris is an angled structure that projects inferiorly into the mons pubis fat with its most caudal part continuous with the glans clitoris. Because of the shape of the clitoris, the glans is typically seen in a more caudal axial section than the rest of the clitoris. In the more caudal sections the urethra and vagina are not distinct and the caudal limit of the bulbs is just visible lateral to the urethra. The glans is the most distinct clitoral structure in these sections. In some women the urethral meatus was also distinct in the most caudal section.

The cavernous or erectile tissue was highlighted using a fat saturation technique. In this type of scan the fat appeared black and the cavernous structures of the clitoris were bright white. The urethral wall and vagina were also highlighted with this technique, although to a lesser extent than cavernous tissue. Other surrounding tissues, muscle and bone appeared as dark structures, increasing the contrast with the centrally placed cavernous structures. In axial section the clitoris formed a triangular complex with the urethra and vagina, namely the clitorourethrovaginal complex.

The structures best seen are the vessels of the neurovascular bundles arising from the pelvic side wall, where the terminal component of the pudendal neurovascular bundle bifurcates into perineal and clitoral divisions to supply the clitorourethrovaginal complex. The perineal division is also best seen while the clitoral division, which ascends along the inferior pubic ramus adjacent to the crura, is best seen in figure 3. The neurovascular bundle is cranial to the clitoral body. The autonomic cavernous neurovascular supply to the clitoris is not visible on these MRI studies. The large clitoral neurovascular bundles on either side ascend along the ischiopubic ramus to the under surface of the pubic symphysis in the midline, from which they run along the cephalad surface of the clitoral body toward the glans. These bundles, which were easily seen using dissection techniques, were not large enough to be visible consistently on MRI, although fat saturation is known to highlight the vascular structures.

Sagittal scans demonstrated the angled clitoral body and glans projecting into the mons on the under surface of the symphysis pubis. The bulbs and crura were also visible in more lateral sections, although not well displayed. Coronal sections revealed the 2 corpora forming the body and ending as the glans clitoris. The body was seen attached to the under surface of the symphysis pubis. The labia minora and majora were well seen in this coronal section. The glans is visible extending more dorsal toward the anus because of its tendency to curve dorsal and caudal.

Bulbar anatomy is best displayed in axial views and it was seen to a limited extent in sagittal and coronal views in all women. The bulbs met ventral to the urethra. Dissection studies have shown that they are not continuous across the midline.4 They descend on either side of the urethra and flank the lateral aspect of the distal vaginal wall bilaterally. The bulbs have a more consistent relationship with the clitoris and urethra than with the vestibule. Thus, in this study the bulbs are named the bulbs of the clitoris according to their consistent relationship to the clitoris.

Discussion: MRI studies of the clitoris complement studies previously performed in cadavers4 and reveal the anatomy in healthy, premenopausal nullipara. No major differences were apparent between findings in the cadavers and on MRI, although in cadavers the structures appeared to be atrophic, as would be expected because of the advanced age of most specimens and other reasons.

Historical, social and scientific factors appear to be responsible for the poor presentation of clitoral anatomy even in current textbooks. Active deletion of the clitoris as a labeled structure from an early version of Gray’s Anatomy compared with subsequent versions indicates the influence of social factors over science. The medical profession has also had a major influence on female sexuality throughout history, particularly in the 19th century. The widespread practice in Western medicine of clitoridectomy for indications as diverse as epilepsy, hysteria and catalepsy is relatively recent.6 In addition to such factors, anatomists have compounded the poor display of clitoral anatomy by revealing it only in 1 plane. While the sagittal plane may suit the display of an essentially linear structure such as the penis, the clitoris is not well displayed in this plane. The axial plane is the most useful. As a multiplanar modality, MRI reveals each component of the clitoris and complements the information obtained at dissection.

This MRI study of the clitoris revealed each clitoral component in detail. The advantages of MRI over dissection based study are that it reveals anatomy in the living subject and it has the ability to enhance a given tissue because of its relative response to magnetic resonance. The MRI technique of fat saturation enhances cavernous tissue, of which the clitoris is composed. Fat saturation gives each clitoral structure a white appearance juxtaposed to all related structures, which are a shade of gray. Even the urethra and vagina, which are vascular structures, appear relatively gray by comparison to the clitoris. This indicates the highly vascular nature of the clitoris even in the non-aroused state.

Recent research has shown that MRI is capable of demonstrating vascular enhancement that may correlate with female sexual arousal, thereby, showing great promise for sexual function studies. The new, gadolinium based, blood pool contrast agent MS-325 administered intravenously has been found to provide an excellent depiction of the female genitalia in premenopausal and postmenopausal women. The same agent has been shown to be useful in studying changes in female genitalia that occur with sexual arousal. The exact superiority of this contrast enhanced, T1-weighted study over the unenhanced fat saturation technique is not clear. MRI with phased array pelvic and endorectal coils has been shown to be an excellent tool for studying the female urethra and periurethral diseases.7

Objective imaging techniques such as MRI and even photography help overcome the inaccuracies associated with diagrams. The structures least well described in anatomical textbooks to date are the bulbs. Typically their relationship to the clitoris and urethra is not acknowledged or in fact said not to exist. The bulbs are usually drawn as if they pass alongside the vaginal introitus, forming the core of the labia. MRI clearly shows the extensive relationship between the urethra and bulbs, and also reveals how these structures are intimately related to the crura and corpora forming the root of the clitoris, an anatomical structure mentioned in some recent anatomical textbooks.9 The view of the bulbs afforded by MRI shows even more clearly than with dissection that the bulbs on either side continue anterior to the urethra and meet together in the midline without merging. The exact role of the bulbs in urethral support and sexual function is unclear. Recent study has suggested they have a significant role in urethral continence. The concept of the clitorourethrovaginal complex is not new, having been called by French investigators after ultrasound based studies the “ensemble uretroclitoridovulvaire.”

Previous studies have used confusing terminology or techniques that have failed clearly to demonstrate clitoral anatomy. Recently MRI of couples copulating have been shown in sagittal section, the plane which in these studies least clearly displays the clitoris. In the same study the male subject only was administered sildenafil, relatively enhancing the signal intensity of the penis and further obscuring the clitoris. In another MRI study in which a woman with true hermaphroditism was depicted13 the term corpus spongiosum was used in reference to the bulbs. In this study the clitoris was noted to be barely visible, part of the difficulty again being the choice of plane, ie sagittal rather than axial, the latter being the plane of preference for clitoral anatomy.

Conclusions: We observed that normal clitoral anatomy in healthy volunteers can be well displayed by MRI using fat saturation techniques without using any contrast agent. The bright erectile tissue of the clitoris surrounds the urethrovaginal complex anterolaterally. The bulbs are recognized as parts of the clitoris and they should be preferably called bulbs of clitoris rather than vestibular bulbs. Axial views are more useful for depicting most of the clitoris, and the sagittal and coronal planes are complementary. This study complements cadaveric studies of clitoral anatomy and provides further insights into the role and scope of MRI for demonstrating normal anatomy.

Professor John Hutson, Royal Children’s Hospital, Melbourne supervised the dissection based female urogenital anatomy project.

Credits: HELEN E. O’CONNELL and JOHN O. L. DeLANCEY

For Figures:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1283096/

Posted November 10, 2012 by dranilj1 in Medicine

Tagged with , , , ,

Do Sensual Excesses Really Sell?

Flashy magazine ads portraying lewd women may not catch the eyes of female readers, according to recent research. The advertising industry bases its success on consumers being drawn to their products. But when it comes to selling in magazines like Allure and Glamour—publications with a female readership of nearly 100 percent—what do consumers want? To find out, a team of researchers at the University of Florida in Gainesville gauged the emotional responses of more than 100 college-aged women to photos of attractive women. After looking at each photo, the participants would point to a manikin that represented their emotional reaction. For instance, one set of manikins represented arousal reactions; ranging from disinterested to excite.

The more seductive the model, the more it left the women bored and uninterested, according to lead author Robyn Goodman. The findings seem to contradict the sensual images that saturate the ads in glossy female magazines. It seems they missed the mark here. The results also illuminate a gap between the male executives who are marketing the magazines and the consumers.

What is beauty?

In an initial survey, participants were asked to rate photos of models according to six beauty categories, including lewd kitten and classic feminine. These beauty types were determined by fashion editors at New York magazines. But rather than distinguishing between six beauty types, the participants only saw two types. After analyzing the data, it was found that female consumers only saw two types of beauty; wholesome and lewd-sensual. For instance, Katie Holmes is an example of wholesome while the Victoria’s Secret models are lewd-sensual. The study was presented at the Association for Education in Journalism and Mass Communication convention last month in San Francisco.

Message to advertisers based on this research; it is evident that many advertisers may have been misled in using more lewd models to attract women to their products. What do women want? Presumably, women desire to be more like the wholesome beauty models, and in turn, will purchase the products they endorse more readily than they would a product endorsed by a more overtly lewd model. The researchers did discuss whether or not clothing or posture had any effect on the results. They thought it was mostly a look and not necessarily those other characteristics such as attire and pose. They hope to test this theory by showing images of the same women in different attire and poses.

Indeed, this study seems to show the fallacy in the age-old adage that “lewd sells."

Incomprehensibility of the Mind

 

Incomprehensibility of the Mind

Much of what we don’t understand about being human is simply in our heads. The brain is a befuddling organ, as are the very questions of life and death, consciousness, sleep, and much more. Here’s a heads-up on what’s known and what’s not understood about your noggin.

When you wake up in the morning, you might perceive that the Sun is just rising, hear a few birds chirping, and maybe even feel a flash of happiness as the fresh morning air hits your face. In other words, you are conscious. This complex topic has plagued the scientific community since antiquity. Only recently have neuroscientists considered consciousness a realistic research topic. The greatest brainteaser in this field has been to explain how processes in the brain give rise to subjective experiences. So far, scientists have managed to develop a great list of questions. Living forever may not be a reality. But a pioneering field called cryonics could give some people two lives. Cryonics centers like Alcor Life Extension Foundation, in Arizona, store posthumous bodies in vats filled with liquid nitrogen at bone-chilling temperatures of minus 320 degrees Fahrenheit (negative 195 degrees Celsius). The idea is that a person who dies from a presently incurable disease could be thawed and revived in the future when a cure has been found. The body of the late baseball legend Ted Williams is stored in one of Alcor’s freezers. Like the other human popsicles, Williams is positioned head down. That way, if there were ever a leak in the tank, the brain would stay submerged in the cold liquid. Not one of the cryopreserved bodies has been revived, because that technology doesn’t exist. For one, if the body isn’t thawed at exactly the right temperature, the person’s cells could turn to ice and blast into pieces.

Living forever is just for Hollywood. But why do humans age? You are born with a robust toolbox full of mechanisms to fight disease and injury, which you might think should arm you against stiff joints and other ailments. But as we age, the body’s repair mechanisms get out of shape. In effect, your resilience to physical injury and stress declines. Theories for why people age can be divided into two categories:

1. Like other human characteristics, aging could just be a part of human genetics and is somehow beneficial.

2. In the less optimistic view, aging has no purpose and results from cellular damage that occurs over a person’s lifetime. A handful of researchers, however, think science will ultimately delay aging at least long enough to double life spans.

In the long-running battle of whether our thoughts and personalities are controlled by genes or environment, scientists are building a convincing body of evidence that it could be either or both! The ability to study individual genes points to many human traits that we have little control over, yet in many realms, peer pressure or upbringing has been shown heavily influence who we are and what we do.

Laughter is one of the least understood of human behaviors. Scientists have found that during a good laugh three parts of the brain light up: A thinking part that helps you get the joke, a movement area that tells your muscles to move, and an emotional region that elicits the "giddy" feeling. But it remains unknown why one person laughs at your brother’s foolish jokes while another chuckles while watching a horror movie. John Morreall, who is a pioneer of humor research at the College of William and Mary, has found that laughter is a playful response to incongruities — stories that disobey conventional expectations. Others in the humor field point to laughter as a way of signaling to another person that this action is meant "in fun." One thing is clear: Laughter makes us feel better.

Some experiences are hard to forget, like perhaps your first kiss. But how does a person hold onto these personal movies? Using brain-imaging techniques, scientists are unraveling the mechanism responsible for creating and storing memories. They are finding that the hippocampus, within the brain’s gray matter, could act as a memory box. But this storage area isn’t so discriminatory. It turns out that both true and false memories activate similar brain regions. To pull out the real memory, some researchers ask a subject to recall the memory in context, something that’s much more difficult when the event didn’t actually occur.

Residing in the hypothalamus of the brain; the suprachiasmatic nucleus or biological clock, programs the body to follow a 24-hour rhythm. The most evident effect of circadian rhythm is the sleep-wake cycle, but the biological clock also impacts digestion, body temperature, blood pressure, and hormone production. Researchers have found that light intensity can adjust the clock forward or backward by regulating the hormone melatonin. The latest debate is whether or not melatonin supplements could help prevent jet lags — the drowsy, achy feeling you get when "jetting" across time zones.

It’s estimated that about 80 percent of amputees experience sensations, including warmth, itching, pressure and pain, coming from the missing limb. People who experience this phenomenon, known as "phantom limb," feel sensations as if the missing limb were part of their bodies. One explanation says that the nerves area where the limb severed create new connections to the spinal cord and continue to send signals to the brain as if the missing limb was still there. Another possibility is that the brain is "hard-wired" to operate as if the body was fully intact — meaning the brain holds a blueprint of the body with all parts attached.

Fruit flies do it. Tigers do it. And humans can’t seem to get enough of it. No, not that. We’re talking about shut-eye, so crucial we spend more than a quarter of our lives at it. Yet the underlying reasons for sleep remain as puzzling as a rambling dream. One thing scientists do know: Sleep is crucial for survival in mammals. Extended sleeplessness can lead to mood swings, hallucination, and in extreme cases, death. There are two states of sleep — non-rapid eye movement (NREM), during which the brain exhibits low metabolic activity, and rapid eye movement (REM), during which the brain is very active. Some scientists think NREM sleep gives your body a break, and in turn conserves energy, similar to hibernation. REM sleep could help to organize memories. However, this idea isn’t proven, and dreams during REM sleep don’t always correlate with memories.

If you were to ask 10 people what dreams are made of, you’d probably get 10 different answers. That’s because scientists are still unraveling this mystery. One possibility: Dreaming exercises brain by stimulating the trafficking of synapses between brain cells. Another theory is that people dream about tasks and emotions that they didn’t take care of during the day, and that the process can help solidify thoughts and memories. In general, scientists agree that dreaming happens during your deepest sleep, called Rapid Eye Movement.

Neuroscience Elucidate Instant Attraction

 

How do you know when you’re attracted to a new face? Thank your medial prefrontal cortex, a brain region now discovered to play a major role in romantic decision-making. Different parts of this region, which sits near the front of the brain, make a snap judgment about physical attraction and about whether the person is Mr. or Ms. Right — all within milliseconds of seeing a new face, a new study from Ireland finds. The research is the first to use real-world dating to examine how the brain makes fast romantic judgments.

To conduct the study, researchers recruited 78 women and 73 men, all heterosexual and single, from Trinity College Dublin to participate in a speed-dating event. Like any typical speed-dating night, participants rotated around the room and chatted with one another for five minutes. After this meet-and-greet, they filled out forms indicating whom they’d like to see again.

But before the speed-dating event, 39 of the participants had their brains imaged. Using a functional magnetic resonance imaging machine, researchers recorded the volunteers’ brain activity as they saw pictures of the people they’d soon meet at the event. For each picture, the volunteers had a few seconds to rate, on a scale of 1 to 4, how much they would like to date that person. They also reported their physical attraction to each person and how likeable they thought each person was.

In the next few days, the volunteers met face-to-face with the people in the pictures, during the speed-dating event. People turned out to be pretty good at knowing who interested them based on photographs alone, the researchers found. Some 63 percent of the time, their initial, photograph-based interest in dating a person was backed up by their real decision after their five-minute speed date. The dating event, incidentally, was all aboveboard, said Jeffrey Cooper, a psychology researcher who conducted the study while he was a postdoctoral student at Trinity College. Participants who "matched" with another study volunteer really did exchange phone numbers, and between 10 percent and 20 percent ended up getting in touch with each other later, Cooper told LiveScience. ‘We joked quite a bit that we hoped there might be a wedding someday, but no invitations have come through yet," he said.

The brain on dating more intriguing was what the brain was doing to make those judgments. The researchers found a link between one specific region of the medial prefrontal cortex, called the paracingulate cortex, and people’s ultimate decisions about dating. This region buzzed with increased activity when volunteers saw photographs of the people they’d later say "yes" to. They think it is especially involved in comparing options against a whole bunch of other options, or some sort of standard. Meanwhile, the ventromedial prefrontal cortex, which sits closer to the front of the head, became especially active when participants looked at faces they thought were attractive. But there was a catch: This region was most active when looking at faces that most people agreed were hot. Of course, people don’t always agree on who looks good. When people saw a face that tripped their trigger but didn’t get great ratings from others, a different region activated: the rostromedial prefrontal cortex, a segment of the medial prefrontal cortex located lower in the brain. That region in this moment may be doing something like evaluating not just ‘Is this person a good catch?’ but ‘Is this person a good catch for me?

That role makes sense for the rostromedial region, because the region is known to be very important in social decisions. Among the judgments this region makes is how similar someone else is to you. Given that people tend to find similar folks attractive as potential mates, the rostromedial prefrontal cortex could be saying, "Hey, this one matches us!" There are two ways to look at the results, published in the Nov. 7 issue of the Journal of Neuroscience. One is that we’re pretty shallow. In the first few milliseconds of seeing a new face, we’re evaluating physical attractiveness, but the rostromedial prefrontal cortex goes a bit deeper, very quickly asking, Yeah, but are they compatible with me? These really are separate processes, but they really are both happening in your head as you make those initial evaluations.

Cool and Sound Good

 

Cool and Sound Good

I have quite a many friends who are mental health professionals and I enjoy the discussion among us friends. I am not mental health professional, but their input is revelations and helps me a lot in handling Critical Care ICU patients all the time. Especially, intriguing is the discussion thread called – what are some of your favorite quotes that have motivated and inspired you? They are quotes that they share with patients or with each other, or that they just think are cool and sound good. Gist, I paraphrase in this post.

Life is not measured by the number of breaths we take, but by the moments that take our breath away. If you can keep your wits about you while others are losing theirs and blaming you, the world will be yours. Give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime. If there is one lesson that I have learned during my life as an internist, it is the lesson that what my patients tell me is likely to be true – that many times when I believed that I was right and my patients were wrong, it turned out, though often only after a prolonged search, that my rightness was superficial, whereas their rightness was profound.

You cannot solve a problem from the same consciousness that created it. You must learn to see the world anew. People that judge don’t matter. People that matter don’t judge. The only time a man should be looking down at another man is if the other man is on the ground and the man looking down at him and extending his hand to him so that he can help him up. Creativity exists in the spaces between ideas. Resentment is like drinking poison and waiting for the other person to die.

Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming — WOW — What a ride! Our deepest fear is not that we are inadequate. Our deepest fear is that we are powerful beyond measure. It is our light, not our darkness, that most frightens us. We ask ourselves, who am I to be brilliant, gorgeous, talented, and fabulous? Actually, who are you not to be? You are a child of God. I have not failed 10,000 times. I found 10,000 ways that won’t work. The beauty of balance is that I can do it all and not feel bad about my choices; because every moment is an opportunity to start all over again. Life is a kaleidoscope, so turn your head to a different angle and you see it a whole new way.

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