Ukuthunga imisonto ephindwe kabini kunye nezandla ezinwebekayo - Ezi glavu ziluncedo zibonisa umsonto ophindwe kabini okunika ukhuseleko oluzinzileyo.Uyilo olunwebekayo lwesandla, lusenza kube lula ukunxiba/ukuvala iiglavu, luya kugcina ubumdaka kunye nobutyobo bungaphandle kweglavu.