Indian Thumb Print

[Jerry Kopp <jkopp@ohio.net>]

Looked at a horse today for my children, an arab/quarter cross - nice quiet
kids horse.  She had an odd mark ( more like an indentation)  where her left
shoulder and neck meet.  The owner called it an Indian Thumb Print, said she
was born with it.  I had never seen or heard of this.  Anyone ever heard of
this and what causes it?  It wasn't a scar, just a thumb shaped indentation
in her neck, not tender or anything.  Should I be concerned?  

Thanks,
Roxanne
NE Ohio