Ozveren M Faik, Türe Uğur, Ozek M Memet, Pamir M Necmettin
Department of Neurosurgery, Firat University School of Medicine, Elazig, Turkey.
Neurosurgery. 2003 Jun;52(6):1400-10; discussion 1410. doi: 10.1227/01.neu.0000064807.62571.02.
Compared with other lower cranial nerves, the glossopharyngeal nerve (GPhN) is well hidden within the jugular foramen, at the infratemporal fossa, and in the deep layers of the neck. This study aims to disclose the course of the GPhN and point out landmarks to aid in its exposure.
The GPhN was studied in 10 cadaveric heads (20 sides) injected with colored latex for microsurgical dissection. The specimens were dissected under the surgical microscope.
The GPhN can be divided into three portions: cisternal, jugular foramen, and extracranial. The rootlets of the GPhN emerge from the postolivary sulcus and course ventral to the flocculus and choroid plexus of the lateral recess of the fourth ventricle. The nerve then enters the jugular foramen through the uppermost porus (pars nervosa) and is separated from the vagus and accessory nerves by a fibrous crest. The cochlear aqueduct opens to the roof of this porus. On four sides in the cadaver specimens (20%), the GPhN traversed a separate bony canal within the jugular foramen; no separate canal was found in the other cadavers. In all specimens, the Jacobson's (tympanic) nerve emerged from the inferior ganglion of the GPhN, and the Arnold's (auricular branch of the vagus) nerve also consisted of branches from the GPhN. The GPhN exits from the jugular foramen posteromedial to the styloid process and the styloid muscles. The last four cranial nerves and the internal jugular vein pass through a narrow space between the transverse process of the atlas (C1) and the styloid process. The styloid muscles are a pyramid shape, the tip of which is formed by the attachment of the styloid muscles to the styloid process. The GPhN crosses to the anterior side of the stylopharyngeus muscle at the junction of the stylopharyngeus, middle constrictor, and hyoglossal muscles, which are at the base of the pyramid. The middle constrictor muscle forms a wall between the GPhN and the hypoglossal nerve in this region. Then, the GPhN gives off a lingual branch and deepens to innervate the pharyngeal mucosa.
Two landmarks help to identify the GPhN in the subarachnoid space: the choroid plexus of the lateral recess of the fourth ventricle and the dural entrance porus of the jugular foramen. The opening of the cochlear aqueduct, the mastoid canaliculus, and the inferior tympanic canaliculus are three landmarks of the GPhN within the jugular foramen. Finally, the base of the styloid process, the base of the styloid pyramid, and the transverse process of the atlas serve as three landmarks of the GPhN at the extracranial region in the infratemporal fossa.
与其他较低的颅神经相比，舌咽神经（GPhN）在颈静脉孔内、颞下窝以及颈部深层中位置较深，不易显露。本研究旨在揭示舌咽神经的走行，并指出有助于其显露的标志。
对10个注射了彩色乳胶的尸体头部（20侧）进行舌咽神经的显微外科解剖研究。标本在手术显微镜下进行解剖。
舌咽神经可分为三个部分：脑池段、颈静脉孔段和颅外段。舌咽神经的根丝从橄榄后沟发出，走行于第四脑室外侧隐窝的绒球和脉络丛腹侧。然后神经通过最上部的孔（神经部）进入颈静脉孔，并被一个纤维嵴与迷走神经和副神经分开。蜗水管开口于该孔的顶部。在尸体标本的4侧（20%），舌咽神经在颈静脉孔内穿过一个单独的骨管；其他尸体中未发现单独的骨管。在所有标本中，鼓室神经（Jacobson神经）从舌咽神经的下神经节发出，耳支（迷走神经的耳支，Arnold神经）也由舌咽神经的分支组成。舌咽神经在茎突和茎突肌的后内侧穿出颈静脉孔。最后四对颅神经和颈内静脉通过寰椎（C1）横突和茎突之间的狭窄间隙。茎突肌呈金字塔形，其尖端由茎突肌附着于茎突形成。舌咽神经在茎突咽肌、中咽缩肌和舌骨舌肌的交界处（位于金字塔底部）跨过茎突咽肌至其前侧。在该区域，中咽缩肌在舌咽神经和舌下神经之间形成一道屏障。然后，舌咽神经发出舌支并深入以支配咽黏膜。
在蛛网膜下腔，有两个标志有助于识别舌咽神经：第四脑室外侧隐窝的脉络丛和颈静脉孔的硬脑膜入口孔。蜗水管开口、乳突小管和下鼓室小管是舌咽神经在颈静脉孔内的三个标志。最后，茎突基部、茎突锥体基部和寰椎横突是舌咽神经在颞下窝颅外区域的三个标志。
