Main trajectories of nerves that traverse and surround the tympanic cavity in the rat

Abstract

To guide surgery of nerves that traverse and surround the tympanic cavity in the rat, anatomical illustrations are required that are topographically correct. In this study, maps of this area are presented, extending from the superior cervical ganglion to the otic ganglion. They were derived from observations that were made during dissections using a ventral approach. Major blood vessels, bones, transected muscles of the tongue and neck and supra and infrahyoid muscles serve as landmarks in the illustrations. The course of the mandibular, facial, glossopharyngeal, vagus, accessory and hypoglossal nerves with their branches, and components of the sympathetic system, are shown and discussed with reference to data available in the literature. Discrepancies in this literature can be clarified and new data are presented on the trajectories of several nerves. The course of the tympanic nerve was established. This nerve originates from the glossopharyngeal nerve, enters the tympanic cavity, crosses the promontory, passes the tensor tympani muscle dorsally, and continues its route intracranially to the otic ganglion as the lesser petrosal nerve after intersecting with the greater petrosal nerve. Auricular branches of the glossopharyngeal and of the vagus nerve were noted. We also observed a pterygopalatine branch of the internal carotid nerve, that penetrates the tympanic cavity and courses across the promontory.

A standardized surgical technique for rat superior cervical ganglionectomy

“…The anatomical study presented here is consistent with previous descriptions of the cervical sympathetic chain (Hedger and Webber, 1976;Weijnen et al, 2000) and the arterial vessels of the upper neck (Santer and Owen, 1986). Our additional contribution is to describe the anatomical-surgical layers of the ventral neck, emphasizing the anatomical landmarks to reach the SCG and to identify their principal branches to consistently perform different SCG-related procedures.…”

“…To achieve reproducible results and assure laboratory animal welfare, a standardization of the SCGx is needed. Hedger and Webber (1976) and Weijnen et al (2000) provided thorough descriptions of the sympathetic cervical chain with excellent illustrations of the main vascular and nervous structures of the upper neck; however, the anatomical landmarks required to reach the SCG and its branches were not described in detail. In consequence, a surgical anatomy of the region where the SCG is located is needed to achieve a consistent cervical sympathetic disruption with minimal animal morbimortality.…”

Effects and mechanisms of auricular vagus nerve stimulation on high-fat-diet—induced obese rats

“…The detailed neural pathways are very complex, and signals from the NTS could be transferred to a large number of other regions of the brain, including the dorsal motor nucleus of the vagus nerve as a classical vago-vagal reflex, the central nucleus of the amygdale, the hypothalamus, locus ceruleus, etc. All of these extensive connections between the NTS and other regions may be the basic mechanism of AVNS [21,22].…”

Peripheral melatonin mediates neural stimulation of duodenal mucosal bicarbonate secretion

“…It was found in the present study that cutting all nerves around the carotid arteries, in contrast to sympathectomy alone and findings after truncal vagotomy, markedly inhibits the duodenal secretory response to intracerebroventricular phenylephrine (Figure 4). Differences between truncal vagotomy alone and extended pericarotid nervectomy has been observed before in studies of duodenal distension-secretory interactions (18) and may reflect intercommunications between vagal and sympathetic neural pathways at the cervical level (30) and anatomical mixing between these pathways (31).…”