Ma'anar ƙamus na kalmar "cranial nerve" tana nufin kowane nau'i-nau'i 12 na jijiyoyi da suka samo asali daga kwakwalwa kuma suna wucewa ta hanyoyi daban-daban a cikin kwanyar don shigar da yankuna daban-daban na kai, wuya, da gangar jikin. Wadannan jijiyoyi suna da alhakin ayyuka masu yawa kamar hangen nesa, ji, wari, dandano, da motsin fuska, da kuma daidaita yanayin bugun zuciya, numfashi, narkewa, da sauran matakai masu zaman kansu. Kowane jijiyar cranial an keɓance shi ta lamba ta Romawa dangane da wurin da yake da ita da aikinta.