Lambda (λ) sign or twin peak sign.

Josh Billings said one day:
“There are two things in life for which we are never truly prepared: twins.”
…at least now you may prepare a bit earlier for that!

 Lambda (λ) sign or twin peak sign.

Twin peak sign is a sign of dichorionic diamniotic twin pregnancy, which means that each child has its own amniotic and chorionic sacs.

This most commonly occurs in a dizygotic pregnancy, which is when two ova are independently fertilised by two different sperms, creating two separate zygotes.

The twin peak sign is seen on ultrasound examination as a triangularly shaped chorion, which separates between the two twins. The best time for see this sign on USG is in the first trimester (10-14 weeks).

Dichorionic diamniotic (DCDA) twin pregnancies occurs in about 76% of all twin pregnancies.


Case courtesy of Dr Alexandra Stanislavsky, Radiopaedia,org, rID: 13492