TT #127 · Parshas Tazria · Aliyah 2 · Passuk 10
English: If the eruption spreads out in the skin, so that the eruption covers all the skin of the affected person from head to foot, as far as the priest can see,
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:12
Torah Temimah cites Sifra (Toras Kohanim) for the limits of the phrase “from his head to his foot”.
Sifra — Vayikra 13, Midrash Sefer
English: “From his head to his foot” means that the head and foot themselves are not included in the stated endpoints.
Textual derivation
The Sifra reads the endpoints precisely: the phrase covers the span from the head to the feet without including the head and feet themselves.