The simian line is also known as a:

The two most comprehensive simian line-related websites I have found to date can be found here and here.

The simian line’s name stems from its resemblance to the palmar creases found in the hands of primates. In a normal hand, there are three lines intersecting the palm, generally sloping at an angle. These are the head, heart, and life lines. A standard simian line fuses the top two lines (the head and heart lines), into a single, deep line which crosses the palm from one side to the other horizontally, rather than in a curving angle.

The implications of a simian line generally focus on three areas: dermatoglyphics (studying the human hand in relation to biological and organic disorders of an inherited nature), psychodiagnostic chirology (the human hand in relation to disorders of the psyche), and physiology (whether the bearer has a chromosomal disorder).

The Simian line can be the target of negative connotations, and there are many conflicting interpretations of its meaning. Because its name stems from the word for “monkey” and because of its frequency in chromosomal disorders, most notably Down Syndrome (one health website states that simian lines are found in about one half of Down Syndrome individuals and is found in the normal population, depending on sample, in 1-15% of the people studied), many people are concerned about the simian line being a “bad sign.”

As the simian line is a combination of the head and heart lines, it is the frequent assumption of chierologists, dermatoglyphics experts, and palmists that the simian line performs the functions associated with both lines. That is, the bearer finds it difficult to separate emotions and what is desired (the heart line) from intellect and what is thought (the head line). They believe the simian line gives the ability to focus on one thing, absolutely, to the exclusion of all else. It is believed that these people generally achieve and accomplish far more than most, developing techniques and inventions that will last for generations. They also supposedly experience far more misfortune than most, usually due to the same intensity that drives them. The ambition for success in business endeavors will be strong, as will be the tendency to shut out all else in pursuit of these ambitions. People with simian lines are seen as being complex, forceful, goal-oriented, and egocentric.

Religious elements of the simian line are mentioned frequently. Arnold Holtzman, PhD, said that “Many of their numbers may come to identify with fundamentalist religion after living very open, liberal, and free-thinking lifestyles. Quite the reverse may be true, and to the same extreme, with those individuals who may originally have been brought up in very strict and rigid religious environments.” The writers at remark that “Psychological abuse was almost certainly present within your developmental years, probably taking the form of religious dogma. A complete shift in religion is now indicated as part of your life’s current direction—either into or out of a fundamentalist group.” It is stated at that “people who tend to be religious fanatics tend to have a simian line.” The roots of this perceived religious or anti-religious fanaticism probably stem from the single-minded intensity of the simian line which so closely mirrors the devoted intensity of fanaticism.

The simian line may be visualized as an agent responsible for sudden and radical adjustments in an individual’s attitudes, behavior, lifestyle, values, goals, ambitions, and, indeed, identity. Similarly, these radical adjustments may become manifest as new careers in areas these people may never before have considered. The individual, in this instance, may renounce a sound, secure, and long-standing career to devote himself, or herself, to a lifestyle which may be virtually a planet apart from anything hitherto associated with this person. Leaving everything familiar behind them these people may have felt compelled to fit themselves into their new skins, as it were. It is nothing which must necessarily respond to reason or logic inasmuch as this person would invariably attempt, and with much seeming conviction, to prove otherwise. As noted earlier, however, these dramatic developments do not always transpire. They would best be regarded as the exception rather than the rule... as a possibility and not as an inevitable expression of the simian line. Again, it is the “pressure” manifest as chronic, if low-keyed, unrest and general psychical discomfort which would best be the focus of the therapist’s attentions.

This is my simian line. I traced it faintly with a pencil because my palm lines are freakishly thin and faint, and it is nearly impossible for any of them to appear on a scan.


Miscellaneous information found online and in palmistry books:

Excerpts from Palmistry: How to Chart the Lines of Your Destiny, by Roz Levine. Buy it here.

Some athletes possess a combination of the Lines of Heart and Head, known as the Simian Line. Found on any hand, this rather unusual line reveals an intense side to the personality. If this line is found on the hand of someone with an interest in sport, and the hand is strong and sinewy, there can be a love of intense, demanding competitive activity, such as running and cycling.

The Simian Line, where the Lines of Head and Heart combine, can often correspond with an impassioned disposition. This is a relatively unusual sign. Simian types are always intense in some way, although this is not necessarily a negative trait. When it comes to passion, feelings can get out of perspective because emotional reactions can swamp and overwhelm reasoning. Such people need understanding partners. A Simian Line found on the left hand often contributes to fundamental sensuality. Together with a full Mount of Venus, love, desires, and passions are even more amplified. If the Simian Line and…a pronounced Mount of Venus were found on the right hand instead of the left, then the combination would have a very different meaning. Sensuality and passion could be different to cope with. If the Simian Line and large Mount of Venus were found on both palms, then life would be ruled by unbridled passions, probably with dire consequences. As the Simian Line appears only on his left hand, Philip will have a basic tendency to experience life on an intense level. His energies are condensed, in that the thinking and feeling sides of him combine to create determination and a terrific ability to concentrate. His Simian Line is found in the usual position of the Line of Heart, which reveals that the feeling side of Philip dominates. A line set lower on the hand would mean that the intellect rules the feelings.

The Lines of Head and Heart are usually separate, but sometimes you will see a palm that appears to have a Line of Head but no Line of Heart, or vice versa. In either case, what you are looking at is a combination of the two, called the Simian Line. The Simian Line is likely to be found on the palms of people who have a strong tendency to be ‘a law unto themselves.’ The word simian means monkey-like, but do not assume that the owner of such a line will bear any behavioral resemblance to a monkey. This line involves emotional and other responses… People with this line can find some aspects of relating to others problematic. They may need to understand how this line manifests in their lives and how best to handle the energies created by it…when separate, the Lines of Head and Heart allow objectivity and reason to rationalize and temper emotional balance because thoughts and feelings are combined. It is quite rare to find a pure Simian Line on both palms; owners of such will be very subjective and willful. They will not easily adhere to the usual norms of society, but will be a law until themselves. In extreme cases, they will be completely ruled by passions and instincts and the law of the jungle will apply, hence the name given to the line. …This type often feels a lot of tension and internal pressure as everything is experienced in an acute way; this can give way to unreasonable outbursts, which can be aggressive. A violent tendency is found when other features, as well as the Simian Line, are present. If the thumb is very straight with no waist, a lack of reason will be very marked. When the Simian Line is found on both palms, look out for a short thumb. If it is very bulbous at the top and does not bend back easily under pressure, a violent temper is likely. It may be a good idea to avoid aggravating the owner of such a palm.

If the hands, apart from having Simian Lines, are otherwise normal—and especially if they are flexible—negative traits will be less defined. There can often be a great depth of highly creative energy simmering under the surface, which, if given the opportunity in terms of education and environment, can manifest itself in a powerful, highly individual way.
For a pure simian type—someone with a very defined Simian Line on both hands—all areas of life are experienced with enormous intensity. Powers of concentration can be tremendous as everything on a mental level is also felt emotionally and all feelings simultaneously register mentally. Whatever is chosen in terms of work is therefore crucial as it will be far better to apply concentrated energies to demanding tasks rather than to other people. Emotions can be so caught up in thought that responses can be, or seem to be, cold and unfeeling. Often, there is little comfort to be found in relationships as the element of sharing can be in short supply. The deep sensitivity of many simian types registers so subjectively that experiencing closeness and harmony in a relationship can be very difficult.

If this line is to be found on the left hand only, it can tell of a rather sheltered early life, or one where the child felt alienated, lonely, and misunderstood and apart from the rest of the family. There will be a tendency to either shun responsibility especially in early life, or at least to defy the rules, be wayward and deliberately awkward. In the matters of the heart, there can be a relentless attitude, which demands things to be ideal. The subjective nature can make relationships difficult, as it will be hard to make allowances for the other person and to realize that any harm is being done. Normal Lines of Head and Heart on the right hand improve the ability to realize harmonious relationships, but there will always be a basically intense nature, which can require much love and understanding from a partner.

If the Simian Line is found on the right hand only, physical desires can get out of control. Again, the subjective nature and basic tendency to see reason can create problems. When such powerful, concentrated energies are applied to a relationship, love can sometimes find expression only through obsession, as there can be some difficulty in articulating the magnitude of innermost feelings. The need to show such intense emotion may be directed mainly through sexual channels; the owner of such a palm would need a partner who also has a strong sex drive, otherwise the needs of a right-handed simian lover could feel excessively demanding.

If you have a Simian Line on one or both palms and have read some books on palmistry, especially those that were written a long time ago, you may have felt a bit concerned about some of the things that have been said about this line. Certainly it can create some problems in terms of the intensification of all your experiences, especially emotional ones and it can sometimes be difficult for others to understand you. Take heart, however, in the knowledge that it is probably better to feel so deeply than not to feel much at all; that your inner depth is subjective and often passionate-feeling can be a fount of great creativity; and that your powers of concentration can serve you well, depends on how you choose to use them.

When the Simian Line is found in the usual position of the Line of Heart, the emphasis will be on emotional intensity and subjectivity. Reason will take second place. A Simian Line in the usual position of the Line of Head reveals that the thinking processes are intensified and can deepen the powers of concentration.


Excerpted from Secrets of Palm Reading, by Peter West. Buy it here.

Simian lines: Even normally articulate and quite intelligent people can become power-mad, when the mood takes them. They become so caught up with the need to achieve their aims that nothing, and no one, gets in their way; they are unable to direct their talents as they should. There is always a sense of purpose; they seem different; you feel their ability to control, to always be right and not to make mistakes. They must always have the facts, never probabilities. Social niceties will be dispensed with and they become efficient machines; personal popularity is the last thing on their minds. When the simian line lies deep into the palm the emotional side of the nature is badly controlled, but when it is set higher in the hand the intellectual side is more dominant. When this line is fairly thick at its commencement, the personality is quite cold and calculating. If it is more strongly etched toward the outer edge of the hand, the emotions are instinctive. One straight, thick line right across the hands shows a selfish and materialistic nature. A thinner, more lightly etched line implies a highly sensitive inner nature coupled with natural intuition. Reactions are fast but always with that selfish side of their natures in evidence. These folk are often very restless and they cannot stay still for long.

Those with a simian line love or hate with equal intensity. It does not pay to oppose them unless you are sure of your facts.

Those with a simian line are strongly attached to nature, and you will often find them working with animals. In addition, there is a strong appetite for a home... and they are loyal and expect loyalty in return. These people are survivors in the original sense, which means they are pragmatic—and just a little suspicious of others. ...They are salt of the earth, and many have wonderful senses of humor ..they value their privacy and are fiercely protective (sometimes too protective) parents.


From Palmistry Revolution, by Yasuto Nishitani. Published by Destination Handguide Publications, licensed from Tachibana Shuppan Inc., Japan.

“The holder of the Simian Line is also referred as a ‘Hyaku-nigiri’—one that can grip a hundred in his hand. With good luck, he is the ruler of a kingdom; with bad luck, he rules the Yakuza (Japanese mafia). In reality, some well known ‘Hyaku-nigirs’ were the Tokugawa Shogun and three past Prime Ministers of Japan. You could say that they have ruled a kingdom. Others are the master conductor Seiji Ozawa and a long list of prominent personalities in television, academia, the arts, religion, and in business.”


Spotted at

If the heart line is not present in the hand (by this I mean that there is only one line traveling horizontally across the palm, called the line of Simian.), this traditionally raises concerns about the emotional nature of its owner. It isn’t that they have don’t have feelings, it is just that they aren’t comfortably balanced about the expression of their feelings. The line of Simian is a blend of the head and heart lines. There are periods of time when the line of Simian person may be very overly emotional and then at other times be almost devoid of any emotion or sympathy. So the owner of such a line usually tends to be more mental in their approach to love. This makes them think through their emotions giving them the sense that they are in control with their feelings about their “significant other.” They will also be naturally oriented towards being more concerned about the practical matters of their relationship, such as ! money, position, or the career of the partner or themselves and how these matters will help the relationship they enter to be fulfilled.

The line of Simian is often seen in the palm of a person who is gifted mentally even to the point of genius. They are very often materially successful individuals and usually attract valid security into their marriages. Personally, I have read for and seen many kind and dear individuals with this line who are in happy long-term marriages. This is especially true when the mate understands their emotional makeup and their unique expression of it.


Every week I receive at least 2-3 questions concerning the line of Simian…A decade ago the Line of Simian was less common for a palmist to see in palms. You might find one hand had it while the other had a head and heart line showing. However lately it seems the Line of Simian is in more individuals’ hands. Also I am finding it to show up in both hands of the same individual.

This line certainly has receive some negative statements about its meaning in the past. In some palmistry books it can be associated with less intelligence and some negative personality traits. I have done more research lately on those who have this line. From what I have observed - and I have observed quite a few people with this line to a great extent - I find that these individuals are intense and very dedicated to their purpose. Their ability to focus upon their current duty or creative project is awesome. They have great follow through because of this ability to focus their energy on the goal at hand.

I have also noted that these people need to be out in nature. They need a good amount of their time of each day outdoors. I am curious if they are in some way related to the nature beings in spirit. Maybe they have had many past lives working with nature and nature beings for a purpose of study or income. I see that they often have special gifts with animals and plants. They are wonderful with animals because of a special deep level of love and understanding they empathy for the animal kingdom.

We are definitely seeing more palms with the line of simian present. I have decided it might be a message to the person from their soul to set aside time to be outdoors and to be with nature for personal health, happiness and comfort. We live in a technically and urban oriented world in which we as humans forget our body and soul’s deep tie to nature for nourishment. Maybe the presence of this line is to remind the owner of this need for them selves and for all of humanity.

I have seen Line of Simian people do great things in a community such as have a special piece of land dedicated as a public park. I also know one lady who has land set aside as a protectorate for wolves. I place a special sensitivity to nature, animals and to other with the line of Simian.

A case study involving simian lines can be accessed here.

Drug addicts and murderers and Tony Blair, oh my!:

Tony Blair’s hands may be telling us something which his smile does not—his emotions are triggered by his intellect. The Prime Minister’s palms reveal a “simian” line, where the head and heart lines merge—a chierological phenomenon seen in about 2.5 per cent of men. Palmist Rupert Alison explains: “Tony Blair is permanently on a mission.” The quirk has not been seen in other leading politicians, but studies show it is more prevalent among drug addicts and convicted murderers.

Found at Dr. Koop’s website:

Prominent creases, called flexion creases, normally appear on the palms of the hands and soles of the feet as part of the hand print and foot print. The palm normally has three flexion creases. Sometimes, the two horizontal creases fuse to form a single crease, called a single palmar crease or a simian crease.

Many structures develop in the first few months of gestation. Palmar creases develop early. Abnormalities in palmar creases may indicate the presence of other associated abnormalities. A single palmar crease or simian crease appears normally in approximately 1 out of 30 people.

Common Causes:

normal finding
Down’s syndrome
Aarskog syndrome
Cohen syndrome
fetal alcohol syndrome
trisomy 13
rubella syndrome
Turner’s syndrome
Klinefelter’s syndrome
gonadal dysgenesis
cri du chat syndrome

Note: There may be other causes of a simian crease. This list is not all inclusive, and the causes are not presented in order of likelihood. The causes of this symptom can include unlikely diseases and medications. Use the Symptom Analysis option to explore the possible explanations for a simian crease, occurring alone or in combination with other problems.

What to expect at your health care provider’s office:
An infant with a simian crease generally has other symptoms and signs that, when taken together, define a specific syndrome or condition. Diagnosis of that condition is based on a family history, medical history, and thorough physical evaluation.

Medical history questions documenting a simian crease in detail may include:
Is there a family history of Down syndrome or other disorder associated with a simian crease?
Have other family members had a simian crease and no other abnormality?
What was the pregnancy like?
Did the mother use alcohol while pregnant ?
What other symptoms or physical abnormalities are also present?
Note: This finding is usually discovered by the health care provider.

The history and physical examination findings will determine whether further laboratory and diagnostic procedures are necessary.

After seeing your health care provider:
You may want to add a diagnosis related to a simian crease to your personal medical record.

Found here:

An interesting property exists between the Line of Head and the Line of Heart—the closer the two are together, the more difficult the bearer shall find it to separate matters of emotion with matters of intellect. As a general rule, the more deeply cut line will prevail as the dominant force behind the bearer’s actions; however, this tension eventually culminates in the merging of two lines into what is called the simian line, so noted because this configuration is more typically noted on monkeys more than man. It carries with it two meanings:

a) The simian line is very commonly found on those people inflicted with Down Syndrome. In fact, some doctors check the hand of a newborn for this sign as an indicator to this malady.

b) The more interesting case, however, is when it belongs to a mentally healthy person; in this case, the bearer has a most peculiar intensity to them, manifesting itself in spells of concentration that cannot be broken by all but the most violent of interruptions, and a vibrant passion for their work. To these people, facts and emotion have merged into one powerful mode of thought, where rational thoughts carry additional facets of pleasure and power, and tender emotions may be carried out with a great deliberation and consideration. It is not that he feels any less than any other man, it is that instead of devoting only one mode to a given situation, thoughts are intensified by the fact that both the faculties of reasoning and emotion are backing them. Such people will carry out their ambitions heedless of the resistance met. They are rarely understood. The question may remain as to whether the emotions or rationality possess greater dominance over the individual. This may be determined by judging the position of the simian line upon the hand. Should it exist where the Line of Heart is expected, emotions are more of a guiding force; likewise will the mind have a stronger reign should the Line appear lower on the hand.

Found on

When the Heart Line and Head Line are fused together, only one major line is present, and it extends all the way across the hand from edge to edge. This is called a “Simian Line”.

The name, adopted many years ago, comes from the fact that some monkeys have only one crease in their palm. Approximately 4% of Caucasians have this line on at least one hand. Approximately 13% of all Asians have it on at least one hand. It is even rarer (1%) to have this line on both hands.

A computer search of the medical literature reveals numerous attempts to link dermatoglyphics (skin markings) to medical disorders. At least fourteen chromosomal abnormalities are listed in the medical literature that have a high correlation (up to 84%) with the occurrence of a Simian Line. Does that mean that every person with a Simian Line is likely to have something medically wrong with them? No! There are many people with Simian Lines that do not have more than the average medical problems.

However, Palmists and Hand Analysts have observed over the years some common traits in people with Simian Lines on one or both hands. [This pertains to those people who have no apparent medical problems.] People with Simian Lines generally live their life differently than most other people who do not have Simian Lines. Not living better nor worse. Just living differently.

In my book, “It’s All In Your Hands,” I describe the two types of Simian Lines, which are Heart Simian or Head Simian type, and tell how individuals with each type differ and live their life. For the sake of brevity here I will just say that both type Simian Lines indicate a challenge.

The challenge for people with either type of Simian Line is to maintain stability in a world that looks very restricted, narrow, and polarized to them. They have strong opinions about how things should be. Seldom are they satisfied to do anything or be anywhere very long. There seems to be an inner tension that never allows a feeling of peace. Most things are done with great vigor. Their lives are usually filled with extremes and constant change. When they make a change, they do it immediately and the change is usually huge.

It is interesting that a larger than statistically expected number of people with a Simian Line have made a positive contribution to history. Perhaps this is because they tend not to have a middle ground for compromise. Their world is more black and white and opinionated than most other people. Although they are generally polarized in their thinking, they can easily switch to the opposite position and act as if that was their position all the time. They generally have an exceptional skill or ability.

Spotted here:

Quite infrequently there are people who have a Head Line and Heart Line joined into a single line often called the “Simian Line.” For these individuals there is a real connectedness, a unity of mind and emotion that can either be a great blessing or an exceeding challenge. They can wear their “heart on their sleeve,” be incapable of accepting any form of criticism and find it very difficult to separate thought from feeling. Or, using this sign as a gift, one with a Simian Line can achieve greater balance that leads to an increased understanding of the thoughts and feelings of others.

Spotted in a blog:

Ever since I was little, I’ve noticed that the line in the middle of my hand goes all the way across, whereas most people’s (and my left hand’s) breaks into two lines. I always wondered what this meant. In a college anthropology course, I learned this line was called a Simian line, and in some cultures, it was supposed to denote some mystical characteristics. For me, in the back of my head, I always thought that my soulmate would also have a matching line. Somewhere out there, someone had that line that would match my own. I’ve always examined people’s palms, looking for the line. One of my cousin’s has it. No one else. Until one day, on my second outing with Jason, we were sitting in the courtyard of Japantown, smoking cigarettes...I showed him my hand...asked him if he’d ever seen anything like it....... AND HE HAD THE SAME THING ON HIS LEFT HAND! I was so excited I almost threw up.


With some rare people the heart line combines with the head line to create a single line that crosses the palm. This is called the simian line and tells that you are a very intense person whose head rules their heart. If the other hand shows a separate heart line or there are some curving horizontal lines above the simian line, then potential for loving is still good, although the intensity remains.

From a pediatrics site:

Concerned about a Newborn’s Simian Crease
“What’s the significance of a unilateral single transverse palmar crease in an otherwise normal newborn?” wonders P. CONNICK, MD, of Calgary, AB.
Since palmar creases are evident by 11 or 12 weeks of fetal life, abnormalities in them suggest that a possible embryologic defect has occurred prior to this time. In the general population, over 90% of people display two transverse palmar flexion creases. However, about 4% of normal people have only a single transverse skin crease—known as a simian crease—on one of their hands, while another 1% have bilateral simian creases. The most common condition usually associated with simian creases is, of course, trisomy 21, although syndromes other than Down’s are also associated with them, such as trisomy 8 and Roberts’ syndrome. If there's no dysmorphism, I wouldn’t investigate a healthy child having a single transverse palmar skin crease, especially if it’s unilateral.

Found in an online guestbook:

“Hi my name is Ian Scott, I am 36 yrs. old. I have quick question about the simian line. My mother is an Aries and has a simian line on her right hand only. My brother, 4 yrs. my elder, is a Sagittarius and has simian lines on both hands, and is considered a genius (158 IQ) My oldest boy will be 3 yrs. old in April (Aries) and has a simian line on his right hand only. My second son is 3 months old, (Sagittarius), and has simian lines on both hands. Can you make any comments or give me any insight into what this might mean, if anything?”

Found in the Spirit Eagle Newsletter:

QUESTION # 1: What is the meaning of having just one line traveling horizontally across my palm?

ANSWER: When there is one line instead of two lines marking the palm horizontally, this is called the line of Simian. Usually there are at least three lines in a palm. The head line, heart line, and the life line. But when the Simian line is present there are no separate head and heart line markings. When you read palmistry books you will find that the Simian line can receive a lot of “bad press,” plus there is much conflicting data as to its meaning. Most of the people who have asked this question were very concerned about this line being a “bad sign.” I practice observing the people I read for my own data collection about hands. Those who have this line that I know personally and as clients have helped me form my ideas of what this line represents. Remember when determining the influence of this line it is important to check to see if it is in both hands. Often it is only in one hand. As usual, I will repeat myself telling you that you have to see at least two other marks to back up what any one line or mark demonstrates. So with that in mind here are some traits of the Simian lined personality:
1. They are usually very energetic about anything they do.
2. They tend to see things as either black or white, no shades of gray in their perception.
3. Since the line is a combination of the heart and head lines they will approach their goals totally mentally or be all emotional in a situation. It seems they do not blend mind and emotion easily. This creates a single mindedness in their personality which I have found allows for tremendous focus and ability to follow through on promises and goals. I see them as devoted and persevering.
4. They are creative and often driven to do their creative thing. It is reported Steinbeck had two lines of Simian.

Spotted at

Simian Line: A special type of head line, which can be found in some cases of intellectually handicapped children, as well as some subjects who may be mentally normal or above average, is the Simian line. This formation is present in the majority of cases of Down Syndrome and in other types of birth defects.

The most distinctive feature of the Simian line is the apparent fusion of the lines of head and heart into one line which crosses the palm from one side to the other. In assessing a person’s behavior from hands, the presence of a Simian line is an important indication, as the subject will be found to have an extreme pattern of behavior. They are often strong minded, headstrong types, whose emotions may range from deep intensities of love or hate to coolness and indifference.

The Simian line is present in approximately 3% of the population. Where other positive features are present in the hands, the owner of this line will have a strong drive to achieve success. If found on a crudely formed hand, with negative traits, it is likely to belong to a misfit or an antisocial person. At the other extreme, a Simian line could belong to a religious fanatic. A great deal of care is needed in interpreting this mark accurately. Children who possess this line will be found to have more behavioral problems than average, unless the meanings of this line are properly understood.

From another palmistry website:

“The simian line runs across the hand replacing the heart and head line. It is a sign of inner tension. It may be destructive or creative or even both. It’s interesting to note that people who tend to be religious fanatics tend to have a simian line. Medicine has also found that simian lines may also be associated with certain types of heart defects. People with a simian line never really find peace. They spend their entire lives searching for an answer they never really find. To the person with the simian line there is only right or wrong and nothing in between. People with this line work twice as hard, study twice as hard and fight twice as hard.

Another palmistry site:

“A number of congenital problems have left their marks on both the brain and the hand. Examples of such associations are the significant increases in palmer single flexion creases (simian line) and...mental retardation in a Down Syndrome...Any changes to the normal incidence of transverse creases (Sidney, simian lines and interrupted transverse creases), will occur very early in pregnancy. By about the eighth week of gestation the thenar crease becomes visible starting on the radial side of the hand between the thumb and index finger. Around the ninth week of gestation, the metacarpophalangeal creases (between the palm and the fingers) are visible and the distal interphalangeal crease barely is visible. The thenar crease continues to be visible. As we progress into the tenth week the proximal interphalangeal creases start to become visible. The 12th week brings signs of the distal transverse crease across the palm starting under the area between the index and middle fingers to later extend to the ulnar margin of the palm. By the thirteenth week both the distal and proximal transverse creases are becoming visible and after the14th week of gestation at the 15th week all palmer creases can be clearly seen.

Spotted on The Stork Site:

Dear Tori, I am new to Stork Site and have a question for you. I have heard that a straight line across the palm of your hand means that you could have been close to being a Down’s Syndrome baby. Since the father of my baby has this trait, I have always had this concern in the back of my mind. It almost sounds silly but I thought perhaps you could direct me to some material on this. There have been no past or present problems in either of our families. I am 38 and this will be my third baby. All my children have delivered naturally at home.

Welcome to Stork Site! You will find it to be a wonderful place to be. What you have heard is an “old wives’ tale” and is not based in fact. Let me explain. When a person does have Down’s Syndrome they can have what is called a Simian fold (the straight line across the palm). This is part of the syndrome. Simply to have a straight line across a palm (such as your baby’s father has) does not have any relation to Down’s Syndrome.

From a medical site:

“Trisomy 21 (Lejeune et al., 1959), one of the most common chromosomal abnormalities in liveborn children, causes Down Syndrome. It is characterized by mental retardation and a distinctive array of facial and other dysmorphic features. These include ... Simian crease and characteristic dermatoglyphics (Epstein,1989). Simian creases are just not that common in the “normal” population. (Although I vividly remember a pediatrician colleague who proudly displayed his own simian creases whenever the subject came up.) But in my five years when I practiced pediatrics, I do not remember seeing one entirely “normal” child with a simian crease....but I do not know the true incidence of single palmar transverse crease (simian crease) in the general population…A pediatric geneticist could check out the baby and also check out the literature and see if there are any reported associations of simian crease and corectopia. One reference that I still use is Smith’s Recognizable Patterns of Human Malformation. In that one single reference, it lists 19 different syndromes where a single simian crease is ‘FREQUENT’ and 13 different syndromes where a simian crease is ‘OCCASIONALLY’ seen.”

Found in The Washington Post, 1/26/97, written by columnist Tony Kornheiser:

Things were going so well, I decided to have Wyndee read my palm also. She told me to extend the hand I write with. I did, and she gasped, “The simian crease!” She called to her mother: “Mom, read his palm. He has the simian crease.” I was alarmed. The simian crease! I might have to climb up the Empire State Building. I moved on to Wyndee’s mom. In short order she told me that I was “inflexible, dogmatic, impatient and self-indulgent—energetically so.”
“You got all that from my hand?” I asked her. “Or were you talking to my family?”
“How old are you, 40?” she asked.
Why was she looking at my palm? Couldn’t she tell by reading the lines on my face?
“Right,” she said. “Closer to 50.”
The simian crease, it turns out, is a big deal. “It occurs,” she said, pointing to a straight line across the middle of my palm, “when your head line and your heart line are fused together. It’s the merging of the mental and the emotional. People who have this search for ideas; they’re very forceful and creative. What do you do for a living?”
“I’m a sportswriter.”
“Well, that’s certainly creative,” she said patronizingly.

Spotted on

“Medical investigators have found the single palmar crease to be associated with a variety of syndromes and congenital abnormalities. Here, in an illustration taken from a book on cheiromancy, the heart and head lines when joined indicate an unusual person. In this one instance, the cheiromancer and the medical examiner are in complete agreement, for a child with a single palmar crease may indeed be unusual.” Johnson and Opitz then give their data: a study of 276 children with a variety of disorders, and 150 well children. They found a higher incidence of congenital abnormalities (52% to 30%), borderline retardation or lower IQ (52% to 33%), and certain types of problem pregnancies (infection and bleeding) in the single palmar crease (also known as the Simian Line) cases. They also found a lower incidence of prematurity and delivery complications. They conclude that the Simian Crease suggests some insult to the fetus in the first trimester and that normal looking infants with the Simian Crease should be watched carefully for later difficulties. I would have liked to have seen figures on the above average IQs associated with single palmar crease hands included in the study. I think it is important to add that in my experience of hundreds of hands with the Simian Line, in almost all cases, these clients were at least of normal intelligence, and some were exceptional.

Found on a medical website:

“The neurodevelopmental hypothesis of schizophrenia proposes that the ‘lesion’ responsible for schizophrenia dates from the development of the brain in-utero or early life, rather than the time immediately preceding overt psychosis. Subtle neurological signs have been reported in longitudinal studies of children at high risk of schizophrenia. Several studies have also demonstrated that people who develop schizophrenia deviate from the general population on a range of childhood cognitive and behavioural measures. One possible set of markers of a teratogenic influence on development are minor physical abnormalities (MPAs): subtle alterations in the development of various structures such as the palate (shape of palate roof), eyes (epicanthic fold), ears (low set ears, adherent ear lobes), fingers (inward bending fifth finger), hands (transverse palmar crease), and toes (spacing between first and second toes, syndactylia).

Spotted here:

Posted by Christine on October 05, 2000 at 00:06:48:
Hi - I'm looking for any MEDICAL information anyone might have on a simian line in a newborn. Searched internet but didn't find a whole lot. Is this indicative of heart disease? Thanx for any info.

Posted by former newborn nurse on October 05, 2000 at 00:40:21:
In Reply to: Simian line (sm) posted by Christine on October 05, 2000 at 00:06:48:
"simian crease. Crease on the palm of the hand, so termed because of its similarity to the transverse felxion crease found in some monkeys. Normally the palm of the hand at birth contains several flexion creases, two of which are separate and approx. transverse. When these two appear to fuse and thus form a single transverse crease, it is termed simian crease. The crease MAY be present in a variety of developmental abnormalities including Down syndrome, rubella syndrome, Turner syndrome, Klinefelter syndrome, pseudohypoparathyroidism, and gonadal dysgenesis."

Posted by Dolores on October 05, 2000 at 00:37:48:
In Reply to: Simian line (sm) posted by Christine on October 05, 2000 at 00:06:48:
It is a simian crease and is found in certain Down syndrome infants. I have tried to give you a link to the online Merck manual where you can read what little is there. If you have a Merck manual, it is on pages 2299-2301. Hope this is what you are looking for.

Found here:

Quite infrequently there are people who have a Head Line and Heart Line joined into a single line often called the Simian Line. For these individuals there is a real connectedness, a unity of mind and emotion that can either be a great blessing or an exceeding challenge. They can wear their heart on their sleeve, be incapable of accepting any form of criticism and find it very difficult to separate thought from feeling. Or, using this sign as a gift, one with a Simian Line can achieve greater balance that leads to an increased understanding of the thoughts and feelings of others.

(among the proof given for evolution):

Greater incidence of the so-called simian line in the palm of the hand. (The simian line is a single division across the centre of the palm, which all apes have but most humans do not. The norm for humans is two lines—the so-called head and heart lines.)

Simian Line: Emotional Intensity, Complex, Forceful, Goal-Oriented, Jealous, Egocentric

Click here or here to see a picture of a simian line in a baby with Down Syndrome

Personal websites I have found belonging to folks with simian lines can be found here, here, and here. On the last site, its creator remarks that “It’s a throwback to our prehistoric heritage when homosapiens developed from ... apes? Down’s syndrome children often have one, but this one is hereditary. It’s supposed to mark the edge of genius and insanity (although our neighbour has two and she’s fine).” This site also shows a picture of his newborn daughter’s simian line.

More to come as I find it!