An implantable anatomical support includes a non-rectangular support body with a plurality of arms extending from the support body; an interconnecting member that is coupled to each of the arms; and an adjustable anchor slidably coupled to at least one of the interconnecting members to permit bi-directional movement along the interconnecting member and so configured to exert a compressive force generating frictional interference between the adjustable anchor and the interconnecting member to inhibit the bi-directional movement of the adjustable anchor along the interconnecting member unless sufficient force is applied to overcome the frictional interference.