Aquarius takes the ankles and the calves by position, and in most modern versions the circulation of the blood as well. That last item is the clearest datable retrofit in the whole scheme, and it makes a useful test of any source that presents melothesia as an ancient and unchanging inheritance.
The circulation of the blood was demonstrated by William Harvey in De Motu Cordis, published in 1628. Before that the prevailing account, from Galen, had blood produced in the liver and consumed at the periphery, with no circuit at all. A first century writer such as Manilius could not have assigned the circulation to any sign, because the circulation was not a thing anyone thought existed.
So the entry arrives after 1628, and in practice much later, in the popularising astrological literature of the nineteenth and twentieth centuries which redistributed the body according to physiology as it was then understood. The same period gave Gemini the nervous system and Cancer the lymphatics.
None of this makes the modern lists worse than the old ones. It makes them modern, and it shows a supposedly fixed correspondence tracking the medical knowledge of whoever was writing it down. The atlas records the assignment and its date, and makes no claim about the circulatory system.
Sources AstronomicaMarcus Manilius with William Harvey's Natural PhilosophyRoger French, Ancient MedicineVivian Nutton