Also written in a less phonetic form "Satcakra-Narupana".
The Satchakra-Narupana is a book, written over five hundred years ago in Sanskrit, by a fellow named Purnananda Swami.
The title means "Description of and Investigation into the Six Bodily Centres"
The book features eight chapters, giving detailed descriptions of the spiritual points of the body, the chakra - or "soul muscles," if you will.
An English translation from the early 1900s is readily available at the website: http://www.realization.org