FIGURE 1-21

     The dura is a pain-sensitive structure - but the arachnoid, pia and the brain itself are not. The dura of the anterior and middle fossae receives sensory endings from the trigeminal nerve (Figure 1-21). The dura of posterior cranial fossa is supplied by branches of the vagus nerve, coming off before it exits from the cranial cavity) and by branches of spinal nerves C2 and C3, that enter through the Foramen Magnum. The significance of this is that irritation of the dura may be perceived (or "referred" to) as coming from sensory territory of the trigeminal or upper cervical nerves.