Reading the hand

The Simian Line: When Head and Heart Are One Crease

Also called the single palmar crease. It's uncommon, it's easy to misread in a photograph, and it carries more myth than almost any other feature of the hand.

Where it is

On most hands, two horizontal creases cross the upper palm: the heart line, below the fingers, and the head line, running out from between thumb and forefinger. On a minority of hands those two are a single crease running straight across the palm. That's the simian line. The name is Victorian and unflattering. Anatomists prefer single transverse palmar crease, which is accurate and dull.

It can appear on one hand or both. When it's on one hand only, a full reading compares that hand with the other, because traditionally they're read as what you were given and what you made of it.

How common it is

Studies vary with population and with how strictly "single" is defined, which is the honest reason you'll see different figures quoted. A full single crease on at least one hand is generally reported in the low single-digit percentages of people. It's more common on one hand than on both, and somewhat more common in men. A larger group has a partial version, where the two lines are joined by a strong bridge but remain distinguishable. Those hands are usually read as ordinary head and heart lines with an unusually close relationship.

What it is, physically

Palm creases form before birth, in roughly the first trimester, along with the ridge patterns Harold Cummins spent his career studying. They're flexion folds, so they don't wear in or wear away. The line you have now is the line you were born with.

What the tradition makes of it

In palmistry the reading follows from the shape. Where most hands keep thought and feeling on separate lines, this hand runs them together, so the traditional interpretation is intensity and singleness of purpose. Someone who doesn't easily separate what they think from what they feel. They throw themselves fully into work or attachment, and find half-measures difficult. Older books lean on darker words like stubborn and obsessive. More recent writers lean on brighter ones like focused and wholehearted. As usual, an honest reading considers both and lets the rest of the hand decide which way it tips.

What the tradition doesn't say, despite the internet, is that the line marks anyone as a genius, a criminal or doomed. Those claims come from nineteenth-century writing that also read character from skull shape. We don't repeat them.

Reading it from a photograph

This is the feature most often mis-identified in a photo. A cupped palm, a flat light source or a strong fold at rest can make a normal head line and heart line look joined. Before reading a simian line, we look for three things:

1. A single clear groove across the palm, not two lines that meet.
2. The same result with the hand relaxed and slightly flexed. A true single crease stays single.
3. Side lighting. Front light flattens creases into each other. The photo guide covers this in five minutes.

If the photograph can't settle it, the reading says so, and reads the two lines as possibly joined rather than pretending to know.

The short version

Uncommon, formed before birth, and read traditionally as thought and feeling running on one track. It isn't a verdict on anything.

Think yours might be one? Photograph your hand from the side and we'll tell you what's visible, and what isn't. Two readings free, no card.