The phrase "nervi labiales posteriores" refers to the posterior labial nerves, which are responsible for carrying sensory information from the back part of the lips. Synonyms for this term include "nervus labialis posterior", "posterior labial branch", and "back lip nerves". These synonyms can be used interchangeably to describe the same group of nerves that innervate the posterior region of the lips. Understanding these synonyms is essential in medical and dental fields, where they are commonly used to discuss the anatomy and function of the nerves in question.