The term "radix posterior" is a Latin phrase used in anatomy to refer to the posterior root of a spinal nerve. Synonyms for this term can vary depending on the context. In medical literature, alternative terms such as "dorsal root" or "sensory root" may be used to describe the same structure. These synonyms highlight the fact that the radix posterior carries sensory information from the body to the spinal cord. Additionally, in some literature, the term "afferent root" can also be used interchangeably to describe the same anatomical structure. All of these synonyms ultimately point to the posterior root of a spinal nerve, emphasizing its role in transmitting sensory signals to the central nervous system.