What does Leviticus 21:20 mean?

If a priest is hunchbacked, too small, has a disease in his eyes, or has a skin condition or damaged testicles, he can't serve at the altar either. Leviticus 21:20 - Modern Text Bible

(The list continues, naming other physical conditions that would prevent a priest from carrying out public rituals. The idea is to keep the ceremonies free from anything seen as a defect or distraction.)