So, the cause of why the finger on the leg is numb may be a banal prolonged immobility of the person, an uncomfortable pose or excessive weight (when the lower limbs are under the weight for a long time).
Ngakho, isizathu sokuthi kungani ithuntubeze uzwane kungenzeka banal isikhathi eside baxhashazwe umuntu ukuma ungakhululekile noma isisindo ngokweqile (lapho izitho aphansi isikhathi eside bangaphansi isisindo).