The phrase "atlas septet" may not have many direct synonyms, as it refers specifically to a set of seven cervical vertebrae in the human neck. However, there are related words and phrases that could be used interchangeably or in combination with "atlas septet", such as "upper cervical spine", "C1-C7 vertebrae", or "neck bones". Additionally, "atlas" on its own can refer specifically to the first cervical vertebra, so it could be used as a synonym in some cases. Overall, while "atlas septet" may not have a clear-cut synonym, there are plenty of related phrases that could be used to describe the same anatomical location.