三叉神经TrigeminalNerve

CRANIAL NERVE ANATOMY颅神经结构,The Trigeminal Nerve or Cranial Nerve 三叉神经,The Trigeminal Nerve,The trigeminal nerve is both motor and sensory to the muscles of mastication(咀嚼肌）and of course also has a large sensory territory.,The Trigeminal Nerve,The trigeminal nerve is the thickest cranial nerve（三叉神经是颅神经中最粗的）. It emerges from the anterior side of the pons by two roots（它自桥脑前方发出两个根）:a sensory root supplying the skin of the face, the facial cavities and the teeth（分布于面部皮肤，面部各腔及牙齿的感觉根）,a motor root supplying the masticatory muscles（分布于咀嚼肌的运动根）.,The Trigeminal Nerve,The trigeminal ganglion（三叉神经节） punctuates the course of the sensory root. The trigeminal nerve distributes three branches:the opthalmic (V1)（眼神经）the maxillary nerve (V2)（上颌神经）the mandibular nerve (V3)（下颌神经）,The trigeminal nerve can be divided in several segments:trigeminal nuclei intra-axial segment （三叉神经核轴内段）cisternal or preganglionic segment（脑池或三叉神经节前段）Meckels cave interdural segment（ Meckels 腔硬膜间段）,The “motor nucleus” is located in the lateral pontine tegmentum and supplies the muscles of mastication and the tensor veli palatini and tensor tympani muscle（三叉神经运动核位于桥脑被盖外侧，并支配咀嚼肌和腭帆张肌、鼓室张肌）.,Trigeminal nuclei intra-axial segment,The “pontine” or “principal” sensory nucleus (PSN), which can be found lateral to the motor nucleus and anterolateral to the fourth ventricle at the level of the root entry zone (REZ), processes discriminative tactile sensation from the skin of the face（三叉神经桥脑核，位于运动核外侧及三叉神经根入桥脑水平的四脑室前外侧,传导辨别面部皮肤的触觉）.,Trigeminal nuclei intra-axial segment,Trigeminal nuclei intra-axial segment,The “mesencephalic nucleus” is a superior extension of the PSN in the midbrain up to the level of the inferior colliculus（三叉神经中脑核是中脑至下丘水平PSN的向上的延伸）. It is the only nucleus in the CNS composed of unipolar neurons（由单极神经元组成）. It receives afferent fibers for facial proprioception（接收面部感觉的传入纤维）(teeth, hard palate（硬腭）, temporomandibular joint TMJ). Their peripheral processes supply stretch receptors in the muscles of mastication and periodontal ligaments of the teeth（其周围突分布于咀嚼肌和牙周韧带的牵张感受器）.,Trigeminal nuclei intra-axial segment,The spinal nucleus is a caudal extension of the PSN and descends from the level of the lower pons down to spinal cord level C3 （三叉神经脊束核是PSN向尾侧的延伸，并自桥脑下行至颈3脊髓水平）. The nucleus merges with dorsal gray matter of the cord（此核延续为脊髓后角的灰质）. This nucleus mainly receives tactile, nociceptive, and thermal information from the entire V1,V2, and V3 trigeminal areas（该核主要接收V1、V2及V3的触、痛及温等感觉）.,Cisternal or preganglionic segment,The cisternal or preganglionic segment leaves the brainstem at the site where the pons is widest in the coronal and axial plane, also called the REZ（脑池段或神经节前段，在冠状位和轴位上均可显示在桥脑最宽的地方出脑干）. The cisternal segment is composed of a sensory and motor root and courses anterosuperiorly through the prepontine cistern, passes over the tip of the petrous apex, and enters the CSF-filled Meckels cave through an opening in the dura mater called “the porus trigeminus” （脑池段由感觉根和运动根组成，通过桥前池向前上方走行，经过岩骨尖，穿过被覆硬膜的三叉神经孔，进入到充满脑脊液的Meckels 腔）.,Cisternal or preganglionic segment,This segment and the sensory fibers inside Meckels cave are best seen on heavily T2W images but can also be seen on high-resolution T1W images（这一段及Meckels腔的感觉纤维在重T2WI上显示最为清楚，在高分辨T1WI上也能看到）.,The preganlionic segment ends in the gasserian or semilunar sensory ganglion（节前神经节段止于半月神经节）. This ganglion always enhances as it has no blood-nerve barrier（由于缺乏血脑屏障，这个神经节通常会强化）. The motor root passes under the gasserian ganglion and leaves the skull through the oval foramen（运动根在半月神经节下方穿过经卵圆孔出颅）. The sensory root divides in an ophthalmic (V1), maxillary (V2), and mandibular (V3) division at the anterior aspect of the Gasserian ganglion.,Meckels cave interdural segment,The ophthalmic nerve V1 division,The ophthalmic nerve courses in the wall of the cavernous sinus, just below the fourth nerve and lateral to the sixth nerve（眼神经穿入海绵窦外侧壁，在滑车神经和展神经外下方走行）. This can be seen as a craniocaudal ovoid nerve, which is much larger than the adjacent fourth and sixth nerves. This nerve can only be depicted in a reliable way on coronal contrast-enhanced high-resolution T1W images through the cavernous sinus（眼神经在增强后的高分辨T1WI冠状位上可以看到）. The nerve then leaves the skull through the SOF and enters the orbit, where it divides into a frontal, lacrimal, and nasociliary nerve providing sensory innervation to the globe, nose, forehead, and scalp（眼神经经眶上裂出颅入眶，分布于眼球、鼻、额部及头皮，主要分支为额神经、泪腺神经和鼻睫神经）.,The maxillary nerve V2 division,The maxillary nerve also courses in the wall of the floor of the cavernous sinus and can sometimes even be found under the cavernous sinus in a dural sheath（上颌神经也是穿入海绵窦外侧壁，有时在海绵窦下方的硬膜鞘内）. The nerve exits the skull through the foramen rotundum and is there always clearly visible on coronal images（经圆孔出颅，在冠状位上显示清晰）.,The maxillary nerve V2 division,The nerve continues through the upper part of pterygopalatine fossa where it gives off several side branches: the posterior superior alveolar nerve, the zygomatic nerve, and two pterygopalatine nerves, which will reach the pterygopalatine ganglion（进入翼腭窝后发出一些分支，上牙槽神经后支、颧神经、2支翼腭神经）. Through these two connecting branches and the Vidian nerve the trigeminal nerve and facial nerve territories are connected. The maxillary nerve has a bayonet course and then reaches the orbit through the inferior orbital fissure (IOF)（上颌神经经眶下裂入眶）.,The maxillary nerve V2 division,There the nerve becomes the infraorbital nerve and follows the floor of the orbit. After giving off the anterior superior alveolar nerve, which can often be seen in the lateral nasal wall, the infraorbital nerve exits the infraorbital foramen and reaches the soft tissues of the midface. The V2 receives sensory information from the midface, cheek, and upper teeth（上颌神经延续为眶下神经至眶底，发出上牙槽神经前支。眶下神经出眶下孔至面部。接收来自面、颊及上牙的感觉信息）.,The mandibular nerve V3 division,The mandibular nerve immediately leaves the skull inferiorly through the oval foramen, and does not run through the cavernous sinus （下颌神经不穿入海绵窦直接经卵圆孔出颅）. In the oval foramen it is joined by the motor root and both nerves continue into the masticator space（在卵圆孔处与运动根一起分布在咀嚼肌间隙）. The motor branch divides in two major nerves just beneath the skull base, the masticator nerve, which innervates all the muscles of mastication, and the mylohyoid nerve, which innervates the mylohyoid muscle and anterior belly of the digastric muscle（运动支在颅底下方主要分出两根神经：咀嚼肌神经支配所有咀嚼肌，及下颌舌骨肌神经支配下颌舌骨肌和二腹肌前腹）.,The mandibular nerve V3 division,The sensory branch divides into the inferior alveolar nerve, lingual nerve, auriculotemporal nerve, and a small buccal branch（感觉支有下牙槽神经，舌神经，耳颞神经和一支细小的颊神经）. The auriculotemporal nerve will finally enter the parotid gland where it connects with branches of the facial nerve（耳颞神经入腮腺并和面神经分支连接）. The lingual nerve connects high in the masticator space with the chorda tympani, again a facial nerve branch. The otic ganglion, located just under the skull base, finally connects the mandibular nerve with the facial nerve via the lesser petrosal nerve（舌神经在咀嚼间隙上与来自面神经分支的鼓索相连，耳神经节位于颅底下方，通过岩小神经连接面神经和下颌神经）.,The mandibular nerve V3 divis