The thumb of the hand or the big toe of the foot. Used in the ordination of priests (Leviticus 8) and the purification ritual for skin disease (Leviticus 14), where blood or oil was applied to the right ear, right thumb, and right big toe — signifying consecration of the whole person.
At Aaron's ordination, Moses applied blood from the sin offering to the tip of Aaron's right ear, the thumb of his right hand, and the big toe of his right foot (Leviticus 8:23–24). The right side represents prominence; ear (hearing), hand (working), and foot (walking) together signify total consecration — every faculty consecrated to God. The same ritual applied to cleansed lepers (Leviticus 14:14), marking reintegration into the covenant community as a complete re-consecration of the person.