scholarly journals Dissection and Exposure of the Whole Course of Deep Nerves in Human Head Specimens after Decalcification

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Longping Liu ◽  
Robin Arnold ◽  
Marcus Robinson
Keyword(s):  
Facial Nerve ◽  
Human Head ◽  
Chorda Tympani ◽  
Tympanic Cavity ◽  
Chorda Tympani Nerve ◽  
Stylomastoid Foramen ◽  
Greater Petrosal Nerve ◽  
Facial Nerves ◽  
Pterygoid Canal ◽  
The Mean

The whole course of the chorda tympani nerve, nerve of pterygoid canal, and facial nerves and their relationships with surrounding structures are complex. After reviewing the literature, it was found that details of the whole course of these deep nerves are rarely reported and specimens displaying these nerves are rarely seen in the dissecting room, anatomical museum, or atlases. Dissections were performed on 16 decalcified human head specimens, exposing the chorda tympani and the nerve connection between the geniculate and pterygopalatine ganglia. Measurements of nerve lengths, branching distances, and ganglia size were taken. The chorda tympani is a very fine nerve (0.44 mm in diameter within the tympanic cavity) and approximately 54 mm in length. The mean length of the facial nerve from opening of internal acoustic meatus to stylomastoid foramen was 52.5 mm. The mean length of the greater petrosal nerve was 26.1 mm and nerve of the pterygoid canal was 15.1 mm.

scholarly journals Active and Adequate Exposure of the Facial Nerve and Chorda Tympani Nerve to Improve the Safety of Cochlear Implantation

2019 ◽  
pp. 014556131987401
Author(s):  
Ling Lu ◽  
Maohua Wang ◽  
Jianfei Dong ◽  
Chuanyao Lin ◽  
Chenjie Yu ◽  
...  
Keyword(s):  
Postoperative Complications ◽  
Facial Nerve ◽  
Semicircular Canal ◽  
Cochlear Implantation ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Horizontal Semicircular Canal ◽  
Facial Recess ◽  
Cochlear Implant Surgery ◽  
Facial Nerves

Background: The posterior tympanum approach of cochlear implantation is easy to damage the facial nerve and cord tympanic nerve. Therefore, we need to improve the safety of cochlear implantation. Objectives: To discuss the safety and feasibility of active and adequate transparent exposure of the facial nerve and chorda tympani nerve during the surgery. Methods: A retrospective analysis was performed on all 945 patients who underwent cochlear implantation from January 2011 to September 2017. All patients have been followed up for 14 months to 5 years postoperatively and postoperative complications have been observed. Results: All 945 patients received artificial cochlear implantation. The facial nerves of 76 cases were above the horizontal semicircular canal plane, while narrow facial recess was observed in 44 cases. Serious chorda tympani nerve variation was found in 1 case. No facial paralysis and facial nerve irritation and abnormal taste occurred after operation. Conclusions: Cochlear implantation with initiative and adequate exposure of facial nerve and the chorda tympani nerve can improve the safety of the cochlear implant surgery. Our study provide a safe and effective method for clinical cochlear implantation to reduce facial nerve and tympanic cord nerve injury.

scholarly journals Conduction velocity of the rabbit facial nerve: a noninvasive functional evaluation

2003 ◽  
Vol 17 (2) ◽  
pp. 126-131 ◽  
Author(s):  
Belmiro Cavalcanti do Egito Vasconcelos ◽  
Cosme Gay Escoda ◽  
Ricardo José de Holanda Vasconcellos ◽  
Riedel Frota Sá Nogueira Neves
Keyword(s):  
Facial Nerve ◽  
Conduction Velocity ◽  
Nerve Conduction ◽  
Action Potentials ◽  
Functional Evaluation ◽  
Surface Electrodes ◽  
Nerve Grafts ◽  
Synthetic Materials ◽  
Facial Nerves ◽  
The Mean

The aim of this study was to evaluate standardized conduction velocity data for uninjured facial nerve and facial nerve repaired with autologous graft nerves and synthetic materials. An evaluation was made measuring the preoperative differences in the facial nerve conduction velocities on either side, and ascertaining the existence of a positive correlation between facial nerve conduction velocity and the number of axons regenerated postoperatively. In 17 rabbits, bilateral facial nerve motor action potentials were recorded pre- and postoperatively. The stimulation surface electrodes were placed on the auricular pavilion (facial nerve trunk) and the recording surface electrodes were placed on the quadratus labii inferior muscle. The facial nerves were isolated, transected and separated 10 mm apart. The gap between the two nerve ends was repaired with autologous nerve grafts and PTFE-e (polytetrafluoroethylene) or collagen tubes. The mean of maximal conduction velocity of the facial nerve was 41.10 m/s. After 15 days no nerve conduction was evoked in the evaluated group. For the period of 2 and 4 months the mean conduction velocity was approximately 50% of the normal value in the subgroups assessed. A significant correlation was observed between the conduction velocity and the number of regenerated axons. Noninvasive functional evaluation with surface electrodes can be useful for stimulating and recording muscle action potentials and for assessing the functional state of the facial nerve.

scholarly journals The depth of the facial nerve in the mastoid bone

2018 ◽  
Vol 4 (3) ◽  
pp. 666
Author(s):  
B. Y. Praveen Kumar ◽  
K. T. Chandrashekhar ◽  
M. K. Veena Pani ◽  
Sunil K. C. ◽  
Anand Kumar S. ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Temporal Bone ◽  
Significant Variation ◽  
Canal Wall ◽  
Stylomastoid Foramen ◽  
Cortical Mastoidectomy ◽  
Canal Wall Down ◽  
Canal Wall Down Mastoidectomy ◽  
The Mean ◽  
Temporal Bones

<p class="abstract"><strong>Background:</strong> The hallmark of the temporal bone is variation. Various important structures like the facial nerve run in the temporal bone at various depths which can be injured during mastoidectomy.</p><p class="abstract"><strong>Methods:</strong> Twenty wet cadaveric temporal bones were dissected. A cortical mastoidectomy was performed followed by a canal wall down mastoidectomy and the depth of the vertical segment of the facial nerve in the mastoid was determined.  </p><p class="abstract"><strong>Results:</strong> The mean depth of the second genu was 13.82 mm. The mean depth of the stylomastoid foramen was 12.75 mm and the mean distance from the annulus at 6’0 clock to the stylomastoid foramen was 10.22 mm.</p><p><strong>Conclusions:</strong> There is significant variation in the average depth of the facial nerve in the mastoid. </p>

scholarly journals Memoirs: The Chorda Tympani and Middle Ear in Reptiles, Birds, and Mammals

1915 ◽  
Vol s2-61 (242) ◽  
pp. 137-160
Author(s):  
EDWIN S. GOODRICH
Keyword(s):  
Facial Nerve ◽  
Middle Ear ◽  
Proximal Region ◽  
Geniculate Ganglion ◽  
Chorda Tympani ◽  
Tympanic Cavity ◽  
Gill Slit ◽  
Lower Region ◽  
Lower Jaw ◽  
Dorsal Edge

A comparison of the development of the various structures of the middle-ear region in the lizard, duck, and mammal, shows a remarkable uniformity in their origin and relation. The first gill-pouch separates off from the epidermis from below upwards; at its dorsal edge is an epiblastic proliferation contributing to the geniculate ganglion. The tympanum is formed between the outer epidermis and an outgrowing diverticulum of the hinder lower region of the first gill-pouch. The chorda tympani is a post-trematic branch of the facial nerve, developing behind the first or spiracular gill-slit, and passing down to the lower jaw between the tympanum and the closing spiracle. The relation of these parts to the skeleton and blood-vessels is (with the exception mentioned below) constant throughout the Amniota, and is only intelligible on the view of Reichert that the proximal region of the columella corresponds to the stapes, the quadrate to the incus, and the articular to the malleus. In the chick the chorda tympani develops as a pre-trematic branch of the facial nerve from its first appearance. In adult gallinaceous birds the chorda passes down directly from the geniculate ganglion in front of the tympanic cavity. This exceptional position is probably due to some secondary modification at present unexplained.

Chemospecific deficits in taste detection after selective gustatory deafferentation in rats

1990 ◽  
Vol 258 (3) ◽  
pp. R820-R826 ◽  
Author(s):  
A. C. Spector ◽  
G. J. Schwartz ◽  
H. J. Grill
Keyword(s):  
Detection Threshold ◽  
Conditioned Avoidance ◽  
Taste Bud ◽  
Taste Receptors ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Before And After ◽  
The Mean ◽  
Taste Detection ◽  
Response To Water

Electrophysiological data support the existence of sodium-specific taste receptors that appear to be limited to the anterior tongue. However, previous behavioral findings suggest that bilateral transection of the chorda tympani nerve (CTn) has minimal consequences on NaCl intake and preference. This study employed a conditioned avoidance procedure to measure detection thresholds to NaCl and sucrose both before and after bilateral transection of the CTn. Rats were trained to maintain spout contact in response to water presentations (70 microliters) and to avoid spout contact when a taste solution (70 microliters) was presented. In experiment 1, all rats (n = 3) showed statistically significant impairments in the detectability of NaCl after bilateral section of the CTn. The mean increase in the NaCl detection threshold was 1.41 log units. In contrast, sucrose threshold in these same rats was marginally affected by CTn section (mean increase = 0.22 log units). Experiment 2 (n = 4) replicated the findings of the first experiment. The mean increase in the NaCl detection threshold was 2.23 log units. Sucrose threshold in these rats was, again, only marginally affected by CTn section (mean increase = 0.83 log units). Histological examination of the anterior tongue from the rats in experiment 2 indicated that the CTn transections were complete. These findings reveal that the anterior oral receptive field (innervated by the CTn) containing only 15% of the total taste bud population is critical for the normal detection of NaCl.

Suprascapular nerve as a donor for extracranial facial nerve reanimation procedures: a cadaveric feasibility study

2008 ◽  
Vol 108 (1) ◽  
pp. 145-148 ◽  
Author(s):  
R. Shane Tubbs ◽  
Robert G. Louis ◽  
Christopher T. Wartmann ◽  
Marios Loukas ◽  
Mohammadali M. Shoja ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Head Rotation ◽  
Suprascapular Nerve ◽  
Suprascapular Notch ◽  
Splitting Technique ◽  
Stylomastoid Foramen ◽  
The Face ◽  
Human Cadavers ◽  
The Mean ◽  
Neurovascular Structures

Object Facial nerve injury with resultant facial muscle paralysis is disfiguring and disabling. To the auhtors' knowledge, neurotization of the facial nerve using a branch of the brachial plexus has not been previously performed. Methods In an attempt to identify an additional nerve donor candidate for facial nerve neurotization, 5 fresh adult human cadavers (10 sides) underwent dissection of the suprascapular nerve distal to the suprascapular notch where it was transected. The facial nerve was localized from the stylomastoid foramen onto the face, and the cut end of the suprascapular nerve was tunneled to this location. Measurements were made of the length and diameter of the supra-scapular nerve. In 2 of these specimens prior to transection of the nerve, a nerve-splitting technique was used. Results All specimens were found to have a suprascapular nerve with enough length to be tunneled, tension free, superiorly to the extracranial facial nerve. Connections remained tensionless with left and right head rotation of up to 45°. The mean length of this part of the suprascapular nerve was 12.5 cm (range 11.5–14 cm). The mean diameter of this nerve was 3 mm. A nerve-splitting technique was also easily performed. No gross evidence of injury to surrounding neurovascular structures was identified. Conclusions To the authors' knowledge, the suprascapular nerve has not been previously explored as a donor nerve for facial nerve reanimation procedures. Based on the results of this cadaveric study, the authors believe that use of the suprascapular nerve may be considered for surgical maneuvers.

Chorda Tympani in Chronic Inflammatory Middle Ear Disease

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P52-P53
Author(s):  
Arun Goyal ◽  
P P Singh ◽  
Gautam Dash
Keyword(s):  
Middle Ear ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Retraction Pocket ◽  
Taste Strips ◽  
Disease Site ◽  
Middle Ear Disease ◽  
The Mean ◽  
The Difference ◽  
A Prospective Study

Objective To study the effect of chronic inflammatory middle ear disease on gustatory function of chorda tympani nerve. Methods A prospective study was performed in 2007 on 85 patients of unilateral chronic inflammatory middle ear disease of both cholesteatomatous and noncholesteatomatous type. Gustatory assessment on both sides of the tongue was performed using dry taste strips. Taste strips were made of filter paper soaked in four different taste solutions of four different concentrations each and dried. The taste score is the number of correctly identified taste strips. Results were analyzed using Analysis of Variance (ANOVA) and t-test. Results Comparison of mean taste scores on the side of diseased ear with normal ear was done. On the diseased side, the mean taste score was 9.16 and on the normal side, the mean taste score was 13.24. The difference between the two was found to be statistically significant (p<0.0001). The results were also analyzed for various other parameters like type, duration, and location of disease. Site of cholesteatoma was found to have a significant effect on the taste score of the diseased side. Patients having postero-superior retraction pocket cholesteatoma had significantly lower taste scores as compared to those having cholesteatoma at other sites (p=0.008). Conclusions A patient of chronic inflammatory middle ear disease already has dysfunctional chorda tympani and is unlikely to notice a change in the taste sensation in the event of cutting of the nerve during the course of an ear surgery.

scholarly journals The Prognostic Value of the Test of Chorda Tympani Nerve Function in Patients with Traumatic Facial Nerve Paralysis

1983 ◽  
Vol 76 (2special) ◽  
pp. 300-306
Author(s):  
Hideo Higashitsuji ◽  
Hiroyuki Kitamura ◽  
Susumu Tamaki ◽  
Kazuhiko Shoji ◽  
Atsuko Ichikawa
Keyword(s):  
Facial Nerve ◽  
Prognostic Value ◽  
Facial Nerve Paralysis ◽  
Nerve Function ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Nerve Paralysis
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