It was the distinguishing mark of the anointing of the high priest, that the holy oil was poured upon his head like a crown (compare Leviticus 8:12).
Uncover his head - Rather, let his hair be disheveled. See the note at Leviticus 10:6.
Related Commentaries of Leviticus 21:10
Leviticus 21:10
10 And he that is the high priest among his brethren, upon whose head the anointing oil was poured, and that is consecrated to put on the garments, shall not uncover his head, nor rend his clothes;