Mo. Const. art. V, § 8

The judges of the supreme court shall elect from their number a chief justice to preside over the court en banc, and the judges of the court of appeals in each district shall elect from their number a chief judge of the district. The terms of the chief justice and chief judges shall be fixed by the courts over which they preside. The chief justice of the supreme court shall be the chief administrative officer of the judicial system and, subject to the supervisory authority of the supreme court, shall supervise the administration of the courts of this state. [Effective - 02 Sep 1976 , see footnote]