The simian line: one single crease across the palm
When the heart line and head line merge into a single crease crossing the palm from edge to edge, palmistry calls it a simian line. Here is what it looks like, what is attributed to it, and why it is simply a normal hand variation.
What the simian line is
A single horizontal crease running from one edge of the palm to the other.
Most palms carry two horizontal lines: the heart line at the top and the head line across the middle. On some hands the two merge into one continuous crease that cuts straight across. That is the simian line, also called a single transverse palmar crease.
It can appear on one hand or both. When it shows on one hand only, the other palm usually has the ordinary two-line structure.
- A perfectly straight single line — a complete merger of heart and head lines.
- A slightly curved single line — read as feeling taking precedence over analysis.
- A partial merger — the lines touch along part of their run, then separate.
- Present on the dominant hand only — read as intensity expressed in how you act.
What palmistry reads into it
Tradition reads the simian line as emotion and reason fused: the person does not separate what they feel from what they think. Hence the classic interpretations around intensity, single-minded focus and difficulty with half-measures.
The strength attributed to it is total commitment — in work, in relationships, in conviction. The risk, in the same reading, is rigidity and difficulty changing course once decided.
Like every marking on the hand, this is a symbolic description of temperament — not a diagnosis and not a forecast.
A normal hand variation
A single palmar crease is a common anatomical variation and occurs in perfectly healthy people. It says nothing about a person's health or development.
Palmistry is not medicine. For any health question the only correct source is a doctor, not a palm.
How to identify it on your own hand
Open your palm in daylight and follow the horizontal creases. If you see one line running from the edge below the little finger across to the opposite side with no second parallel line, that is a simian line.
If you are unsure, photograph both palms and upload them: the AI separates the creases and tells you whether your heart and head lines are distinct or merged.
Frequently asked questions about the simian line
What is a simian line?+
A single horizontal crease crossing the palm, formed when the heart line and head line merge. It is also called a single transverse palmar crease.
Is the simian line rare?+
Less common than the two-line structure, but it occurs in a meaningful share of the population, sometimes on one hand only.
Does a simian line mean a health problem?+
No. It is a normal variation of the palmar creases and appears in healthy people. Palmistry provides no medical information.
What does palmistry say about people with a simian line?+
It is read as emotion and reason unified: intensity, total commitment, and difficulty with partial compromises.
I have it on one hand only. What does that mean?+
On the dominant hand it reads as intensity expressed in action; on the non-dominant hand as an inborn disposition that is not always shown directly.
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