More on "Human Tail" Theory


Staff member
Country flag
Early sonographic detection of a 'human tail': a case report.

Efrat Z, Perri T, Meizner I, Chen R, Ben-Rafael Z, Dekel A.

Department of Obstetrics and Gynecology, Rabin Medical Center, Petah Tiqva, Israel.
Ultrasound in Obstetrics & Gynecology 2001 November

We report on a newborn in whom an echogenic protrusion arising in the caudal region was detected at 12 weeks' gestation. Subsequent ultrasound examinations at weeks 15 and 22 failed to demonstrate this finding. After birth, the infant was found to have a pilonidal sinus. The pilonidal sinus may represent a remnant of the embryonic appendage ('human tail') that usually disappears by the end of the 8th week of gestation. This case might support the theory of congenital pilonidal sinus origin.


Very Helpful
Country flag
This is fascinating and is in-keeping with my mothers theory on why I have a pilonidal sinus. I came home from the hospital as a newborn with it. I'm 42 years old though and there were no sonograms back then. I also have a "preauricular sinus" (hole in ear cartiledge) and I tend to think that these are somehow related to skin closure issues in-utero overall.
Last edited:


New Member
Country flag
I totally agree. I was just telling my mother earlier that I thought it had something to do with us having a tail in utero. Glad to see I'm not alone in this thinking.