三叉神经（Trigeminal nerve）为混合神经，也就是既含有运动神经又含有感觉神经。感觉部分收集来自面部和头部的信息，运动部分则控制咀嚼肌。三叉神经是面部最粗大的神经，它的运动部分从脑桥与脑桥臂交界处出脑，再并入下颌神经，一同经卵圆孔穿出颅部。而它的感觉部分的胞体组成位于颞骨岩部尖端的三叉神经节，三叉神经节又分出三条分支（这也就是它叫三叉神经的原因），第一分支为眼神经（Ophthalmic branch），第二分支为上颌神经（Maxillary branch），第三分支为下颌神经（Mandibular branch）。支配脸部、口腔、鼻腔的感觉和咀嚼肌的运动，并将头部的感觉消息发送至大脑。

The trigeminal nerve (the fifth cranial nerve, or simply CN V) is a nerve responsible for sensation in the face and motor functions such as biting and chewing. The largest of the cranial nerves, its name ("trigeminal" = tri-, or three and -geminus, or twin; thrice-twinned) derives from the fact that each trigeminal nerve (one on each side of the pons) has three major branches: the ophthalmic nerve (V₁), the maxillary nerve (V₂), and the mandibular nerve (V₃). The ophthalmic and maxillary nerves are purely sensory, and the mandibular nerve has sensory (or "cutaneous") and motor functions.