Part 2 book “Localization in clinical neurology” has contents: Cranial nerves IX and X, the cerebellum, the localization of lesions affecting the hypothalamus and pituitary gland, the anatomic localization of lesions in the thalamus, the localization of lesions affecting the cerebral hemispheres, localization of lesions in the autonomic nervous system, and other contents. | 12 Cranial Nerves IX and X (The Glossopharyngeal and Vagus Nerves) Anatomy of Cranial Nerve IX (Glossopharyngeal Nerve) The glossopharyngeal nerve contains motor, sensory, and parasympathetic fibers. The nerve emerges from the posterior lateral sulcus of the medulla oblongata dorsal to the inferior olive in close relation with cranial nerve X (the vagus nerve) and the bulbar fibers of cranial nerve XI (the spinal accessory nerve) (Fig. 12-1 ) [11,45]. These three nerves then travel together through the jugular foramen. Within or distal to this foramen, the glossopharyngeal nerve widens at the superior and the petrous ganglia and then descends on the lateral side of the pharynx, passing between the internal carotid artery and the internal jugular vein. The nerve winds around the lower border of the stylopharyngeus muscle (which it supplies) and then penetrates the pharyngeal constrictor muscles to reach the base of the tongue. Figure 12-1 Ventral view of medulla and cranial nerves IX, X, and XI exiting together through the jugular foramen. Dorsal roots of C1 through C6 in the The motor fibers originate from the rostral nucleus ambiguus and innervate upper cervical spinal cord are also shown. (From Daube JR, Reagan TJ, the stylopharyngeus muscle (a pharyngeal elevator) and (with the vagus nerve) Sandok BA. Medical Neurosciences: An Approach to Anatomy, Pathology, and the constrictor muscles of the pharynx. Physiology by System and Levels. 2nd ed. Boston, MA: Little, Brown, 1986. By The sensory fibers carried in the glossopharyngeal nerve include taste permission of Mayo Foundation.) afferents, supplying the posterior third of the tongue and the pharynx, and general visceral afferents from the posterior third of the tongue, tonsillary region, posterior palatal arch, soft palate, nasopharynx, and tragus of the ear. By way of the tympanic branch of the glossopharyngeal nerve (Jacobson nerve), sensation is supplied to the tympanic membrane, eustachian tube, and the .
