Simian Crease

Also known as: simian crease, simian line, single palmar crease, STPC

What is single transverse palmar crease?

Single transverse palmar crease refers to a single crease across the palm of the hand. In most individuals, there are two slightly offset creases across the palm. Sometimes referred to as simian crease, now more commonly called single transverse palmar crease, or STPC.

What might cause single transverse palmar crease?

STPC occurs in about 1 out of every 30 people. In most cases, it is completely normal and is not related to a medical condition. However, it is more likely to be present in people with certain medical conditions, such as:

• Down syndrome
• Fetal alcohol syndrome
• Aarskog syndrome

How can single transverse palmar crease be treated?

In most cases, no action is needed if STPC is noted on the palms.

When should you seek medical attention for single palmar crease?

For patients with STPC, it might be a cue for their doctor to examine them more closely for any associated medical conditions.

Reviewed by: Katherine Schain, M.S., CGC

This page was last updated on: September 16, 2025 12:51 PM