Nerve communication between the glossopharyngeal nerve, external carotid plexus and the superficial cervical ansa: Human autopsy case

Abstract

The authors encountered a very rare human autopsy case in which the supernumerary branch of the glossopharyngeal nerve and a nerve branch arising from the external carotid plexus communicated with the superficial cervical ansa. This anomaly was observed on the left side of a 71-year-old male cadaver during the gross anatomical seminar at Niigata University in 2004. The nerve fascicle and fiber analyses indicated that the supernumerary branch of the glossopharyngeal nerve separated cranial to the branches to the pharyngeal constrictor muscles, carotid sinus and stylopharyngeal muscle and sent the nerve fibers to the muscular branches to the platysma and the cutaneous branches to the cervical region. Additionally, it was shown that the branch arising from the external carotid plexus sent the nerve fibers to the cutaneous branch to the cervical region. Although the external carotid plexus is primarily postganglionic sympathetic fibers originating from the superior cervical ganglion, the vagus and glossopharyngeal nerves gave off branches connecting to the plexus, and therefore it was not possible to determine the origins of this branch of the external carotid plexus. The present nerve fascicle analysis demonstrates that the supernumerary branch of the glossopharyngeal nerve, which innervated the platysma, did not share any nerve components with the branches to the pharyngeal constrictor muscles, carotid sinus and stylopharyngeal muscle, suggesting that this supernumerary branch may be categorized into the different group from these well-known branches.

Cervical vagus nerve morphometry and vascularity in the context of nerve stimulation - A cadaveric study

“…The given study investigated the detailed morphometry, vascularity and surface topography of the CVN for both invasive and non-invasive VNS. Previous findings that the CVN has previously unknown branching patterns 28 , large variations in topography 29 , and a variety of anastomoses 33 – 36 indicate that the CVN is not as easy to be visualized surgically, underlining the rationale to provide detailed morphometry to improve surgery, stimulate the nerve reliably and to rule out potential effects of nerve irritation such as focal demyelinization 37 . Both morphometric values and spatial alignment in the neck relative to the laryngeal eminence showed large inter-individual variation, supplemented by novel information on the vascular supply of the CVN.…”

Positional Relations of the Cervical Vagus Nerve Revisited

“…Dionigi and coworkers utilized ultrasound in a clinical setting to determine the CVN position and observed variations in 27% of their patients (40). CVN branching (23,24,40,41) and vagal connections to other cervical nerves such as the facial nerve (15,16,42), the hypoglossal nerve (17,18), and the cervical sympathicus (19)(20)(21)(22) were found more frequently. The proximity of the cervical part of the vagus nerve to the cervical sympathicus is depicted in Figure 3b.…”

“…Also, stimulation-induced side effects such as bradycardia (12,24,59), neck and throat pain, coughing, dyspnea, and voice alterations (1,7,10,13) appear to be quite common. A hypothetical explanation for some of these side effects and the lacking therapeutic efficacy might be found in the combination of positional variations of the CVN observed here and in CVN branching quantified elsewhere (23) and vagal connections with other nerves (15)(16)(17)(18)42) or sympathetic ganglia (19)(20)(21)(22) to the effect that pathways other than to the CVN as a target structure may become influenced (Fig. 3b).…”

Human Vagus Nerve Branching in the Cervical Region

“…The vagus nerve has been described to run lateral [ 13 – 15 ] or ventrolateral [ 33 ] and parallel to the carotid arteries, following the aortic arch on the left and the subclavian artery on the right side, with the internal jugular vein lying lateral or posterior to it [ 28 , 34 ]. The vagus nerve supplies branches to the facial [ 35 ], the glossopharyngeal [ 36 ], the accessory [ 37 ] and the hypoglossal nerve [ 38 ] in some cases before entering the carotid sheath. Also, connections to the cervical sympathetic trunk have been described [ 39 – 41 ] for the vagus nerve after entering the thorax and for the recurrent laryngeal nerve [ 42 , 43 ].…”