Fig. 1From: The fifth cranial nerve in headachesSchematic of the Trigeminal System. a: The somatotopic distribution of trigeminal nociceptive afferents terminating in the trigeminal nucleus caudalis [11]. b: Innervation of facial skin areas and its related three branches (V1, V2 and V3). PSN (Principal sensory nucleus CN V), MN (Mesencephalic nucleus CN V), PA (Spinal nucleus of CN V Pars Oralis), PI (Spinal nucleus of CN V Pars Interpolaris), PC (Spinal nucleus of CN V Pars Caudalis). N. = Nerve. G. = GanglionBack to article page