Where the Upper Court is also called the Heavenly Court, tian ting, the Lower Court carries the paired name Earthly Court, di ge, and the two names together reveal a cosmological structure sitting underneath the system's plainer division into hairline, nose and chin. Chinese cosmology has long organized the world around a triad of heaven, human and earth, tian ren di, heaven above, earth below and the human person mediating between them, and mapping that same triad onto the vertical span of a single face, sky at the hairline and ground at the chin, with the human years of the Middle Court in between, is a deliberate borrowing of a much older cosmological pattern into the specific work of physiognomy rather than an incidental naming choice.
The Lower Court itself, running from beneath the nose to the chin, is read as the record of a life's later stretch, roughly fifty onward, and of home, children and the material security a life has managed to accumulate by its end. A full, well rounded chin here completes the reading the Heavenly Court began at the top of the face, so the two named courts bracket the whole vertical reading the way heaven and earth bracket the cosmology the system borrows its names from, with the Middle Court's human years of active effort filling the span between them.