Stylomastoid Foramen Research Articles

Tympanohyal bone in toothed whales and the formation of the tympano‐periotic complex (Mammalia: Cetacea)

A tympanohyal bone is reported in dolphins for the first time. The exceptional occurrence of this element in the bottlenose dolphin (Tursiops truncatus) and its location in a furrow of the tympanic can be taken as a vestige of an ancestral conformation indicating that, in cetacean ancestry, uncoupling of the periotic from the mastoid must have taken place laterally and dorsally to attachment of the hyoid arch and the stylomastoid foramen. There is a good correspondence between morphology and topographical relations of structures surrounding the facial canal in toothed whales and terres-trial mammals (especially perissodactyls and artiodactyls). During early cetacean evolution, the tympanic had to undergo strong modification because of its functional correlation with the periotic. In precetaceans, the tympanic was probably loosely attached to neighboring skull bones, while at the same time it was suspended from the periotic via the tympanohyal. The earliest known cetaceans obviously lost this indirect osseous suspension but retained the peripheral attachments of the tympanic. In advanced archeocetes, two of these attachments are maintained but have shifted onto the periotic. In modern dolphins, the tympanic is in firm osseous contact exclusively with the periotic (tympano-periotic complex). Both elements are isolated from the skull acoustically and form a separate mechanical unit specialized for high-frequency underwater sound perception.

The facial "motor" nerve of the rat: control of vibrissal movement and examination of motor and sensory components.

Rhythmical whisking of the mystacial vibrissae at about 7 Hz during exploration is one of the most conspicuous behavioral patterns in the rat. To identify the final common pathway for vibrissal movement, individual motor branches of the facial nerve, including the posterior auricular, temporal, zygomatic, buccal, marginal mandibular, cervical, stylohyoid, and posterior digastric branches, were cut, either singly or in various combinations. We found that vibrissal movement could be abolished only by transection involving the buccal branch and the upper division of the marginal mandibular branch. To trace back the central origins of the buccal and marginal mandibular, as well as the other branches of the facial nerve, all distal to the stylomastoid foramen, horseradish peroxidase (HRP) was applied to the cut proximal ends of these individual branches. The retrograde HRP labelling in the facial motor nucleus revealed topographical representation of these branches in which the buccal and marginal mandibular branches were represented laterally. The stylohyoid and posterior digastric branches originated from cells in the suprafacial nucleus. Consistent with earlier observations with intramuscular HRP injections, the motoneuronal population devoted to vibrissal movement did not seem to be substantially larger than that for other facial movements. An additional examination was made of the labelled afferent component of the facial motor nerve. We confirmed and extended previous findings that none of the above facial motor nerve branches, except the posterior auricular branch, contained a significant number of afferent fibers originating from the geniculate ganglion, the sensory ganglion of the seventh nerve. In addition, no labelling was seen in the mesencephalic trigeminal nucleus or trigeminal ganglion. These findings, in combination, suggest that, with the exception of the posterior auricular branch, all the facial motor nerve branches, including those involved in vibrissal movement, are almost entirely efferent.

Positional Nystagmus due to Alteration of the Specific Gravity in the Labyrinth

Horizontal positional nystagmus having characteristics similar to ice water caloric nystagmus was induced by injecting heavy water into the rabbit middle ear cavity or facial nerve through the stylomastoid foramen. Furthermore, with general administration of glycerol to normal subjects, horizontal positional nystagmus as with general administration of heavy water to experimental animals was observed. It is possible that alteration of the specific gravity arising from infiltration of heavy water or glycerol into the labyrinth accounts for the manifestation of positional nystagmus. These studies on positional nystagmus may be one of the means to elucidate the mechanism of caloric nystagmus and to examine the function of the human blood-labyrinth-barrier. Key words: positional nystagmus, speci3c gravity, labyrinth, heavy water, glycerol.

Electrophysiological diagnosis of peripheral facial palsy. 1. Clinical study

Electroneurography (ENoG) is an electrophysiological diagnostic method for predicting the prognosis of peripheral facial palsy. It provides an electric stimulation to the facial nerve from the stylomastoid foramen and records mainly the orbicularis oris muscle contraction by surface electrodes, and the prognosis is evaluated in terms of the ratio of the amplitude of the normal side to that of the lesion side (ENoG value). In 175 patients with Bell's palsy seen within 2 weeks after the onset and given a conservative therapy in our department, recovery of the facial movement (May's score modified by Hosomi) at 1, 2 and 6 months after the onset and the appearance of sequelae were examined. Diagnostic criteria of the prognosis were formulated on the basis of the ENoG values within 2 weeks after the onset.The criteria indicated that patients with an ENoG value above 40% almost recovered within a month without any sequela, those with an ENoG value of 20-39% almost recovered within 2 months with a 1/10 incidence of sequela and those with an ENoG value of 5-19% recovered in many cases within 6 months. The incidence of sequela was 1/5 for those with al ENoG value above 10% and 1/2 for those with an ENoG value below 10%. In patients with an ENoG value of 0-4%, the ENoG value was mostly 0% without sufficient recovery even after 6 months in whom the sequela amounted to 1/2.The present criteria provide a larger advantage for precise evaluation than the conventional Esslen's criteria in that the former permits more patient distribution of cases, detailed assessment of the prognosis and quantification of the incidence of sequela. It was also found that 10-19% was a clinical critical limit below which a complete recovery was not expected.

刺激性眼振モデルの作成

KCl and Ca2+ decreasing agents (Na2C2O4, Na-citrate, NaHCO3 and Na2EDTA) injected into the middle ear through the tympanic membrane or the facial nerve through the stylomastoid foramen provoked "Irritative Nystagmus". KCl presumably infiltrated into the perilymph and induced a slight increase of K+ concentration, resulting in decrease of the resting potential of the vestibular nerve or sensory cells in the vestibular labyrinth The solution of the Ca2+ decreasing agent might decrease Ca2+ in the perilymph and alter the excitability of the vestibular nerve or sensory cells in relation to Ca2+ stabilizing action. These effects of KCl and Ca2+ decreasing agents might be responsible for "Irrita-tive Nystagmus" due to continuous excitation of the vestibular nerve or sensory sensory cells. The relationship between these experimental results and the "Irritative Nystagmus" of Ménière's disease are dicussed in regard to K+ or Ca2+ concentration in the perilymph.

The intrinsic vasculature of the cat facial nerve.

Treatment of facial nerve disorders is based in part on assumptions regarding the intrinsic blood supply of the nerve. This study was designed to comprehensively delineate the intrinsic facial nerve microcirculation and its relation to the extrinsic circulation in an animal model. Twenty-eight cat facial nerves were removed intact from brain stem to stylomastoid foramen following intravital fixation. Specimens were studied by gross dissection, silicone injection and tissue clearing, complete vessel counts on serial cross sections of individual nerves, and scanning electron microscopy or transmission electron microscopy. The labyrinthine segment of the cat facial nerve contains strikingly fewer intrinsic blood vessels than the mastoid and tympanic segments. The geniculate ganglion, however, has a distinct, rich vascular plexus. The ultrastructure of the intrinsic facial nerve vessels is similar to other small vessels of the body with tight junctions of the endothelium and overlapping spiral smooth muscle fibers of arterioles, as well as surrounding pericytes.

Facial Nerve Evoked Potentials

Evoked potentials representing both intracranial and extracranial activity have been recorded from the canine scalp after retrograde stimulation of peripheral facial nerve branches. A negative electrode at the vertex and a positive electrode at the ipsilateral mastoid (grounded at the contralateral mastoid) show a monophasic negative stylomastoid evoked potential that appears to be generated from the facial nerve trunk at the stylomastoid foramen. When the positive electrode is moved from the mastoid to the posterior scalp (overlying the foramen magnum), a similar potential with a latency 1.5 msec greater is obtained. This brain stem evoked potential is generated from fibers in the vicinity of the root entry zone and the initial trajectory into the brain stem. A potential of similar latency but greater magnitude is recorded with the positive electrode in the cerebrospinal fluid of the posterior fossa.

Communicatory routes connecting the middle ear, the inner ear and the subarachnoid space via perineural space.

Twenty-one rabbits received injection of Indian ink into the stylomastoid foramen. Observation of the serial sections of their temporal bones revealed Indian ink infiltration into the subarachnoid space, along the facial nerve, the auricular branch of the vagus nerve and the tympanic nerve. Along the acoustic nerve, the infiltration was found as far as the fundus of the internal auditory meatus. In some cases, however, Indian ink reached the subarachnoid space and infiltrated into the scala tympani, scala vestibuli and around the saccule by way of the cochlear aqueduct. These routes are suspected to be a course of spreading infection or tumor cells.

An Attempt of Reduction of Aminoglycoside Ototoxicity by Chondroitin Sulfate given through the Stylomastoid Foramen

An Attempt of Reduction of Aminoglycoside Ototoxicity by Chondroitin Sulfate given through the Stylomastoid Foramen

茎乳突孔注入法によるアミノ配糖体抗生剤の聴器毒性評価と毒性発現機序に関する実験的研究

The ototoxicity of various aminoglycoside antibiotics was evaluated after a single injection into the facial nerve through the stylomastoid foramen and a mechanism of the inner ear damage was studied in rabbits. Tobramycin (TOB), gentamicin (GM), kanamycin (KM), amikacin (AMK) and dibekacin (DKB) were dissolved 100mg/ml respectively, and their 0.04ml were given. Histological findings of the hair cell in 24 hours and 10 days after the injection was observed by the surface preparation technique with a phase contrast microscope. The concentration of these drugs in perilymph and tympanic cavity was concurrently measured by the bioassay method.No hair cell damage was observable in any rabbit decapitated 24 hours after the injection. In the animals decapitated 10 days after the injection, however, the outer hair cells were damaged. The damage of the outer hair cell caused by TOB and GM was more severe than that by KM, AMK, or DKB. These results coincide with the ototoxicic evaluation of these drugs by general administration. There were no differences in the perilymph concentration between these drugs. Therefore it is thought that the difference of the ototoxicity resulting from the aminoglycoside antibiotics is due to the difference of their own otoxicities to the hair cells and not to the difference of their accumulation in the perilymph.In order to clarify a mechanism of inner ear damage after the injection into the facial nerve, the serial horizontal sections of the temporal bones after an injection of indian ink 0.04ml were observed histopathologically. The indian ink was transudated into the tympanic cavity from the dehiscence of the facial nerve and along the stapedius muscle and the auricular branch of the vagus nerve. The indian ink was also observed in the intracranial space and inner auditory canal. There was high concentration of the drugs in perilymph and tympanic cavity. It is concluded that the inner ear damage after the injection of aminoglycoside antibiotics into the facial nerve through the stylomastoid foramen is caused by the drugs, which arrived in the perilymph along the cochlear nerve and through the round and oval window from the tympanic cavity.

Experimental Ménière Attack induced by Injection of the Solutions into the Facial Nerve through the Stylomastoid Foramen

Experimental Ménière Attack induced by Injection of the Solutions into the Facial Nerve through the Stylomastoid Foramen

The facial nerve between the stylomastoid foramen and the parotid: computed tomographic imaging.

A small segment of the facial nerve between its exit from the stylomastoid foramen and its entrance into the parotid is surrounded by fat and, therefore, can be imaged well using modern computed tomography. A small dot can be seen surrounded by fat just beneath the stylomastoid foramen on computed tomographic scan. To verify that this indeed represented the facial nerve, tissue sections and an injection into the mastoid segment of the intratemporal facial nerve were performed. The anatomic correlation and clinical material demonstrating involvement of the facial nerve in this region are presented.

Evaluation of Ototoxicity of Aminoglycoside Antibiotics injected into the Facial Nerve through the Stylomastoid Foramen of Rabbit (Second Report)

Evaluation of Ototoxicity of Aminoglycoside Antibiotics injected into the Facial Nerve through the Stylomastoid Foramen of Rabbit (Second Report)

Diffusion Route of Indian Ink Injected into the Facial Nerve at the Entrance of Stylomastoid Foramen of Rabbit

Diffusion Route of Indian Ink Injected into the Facial Nerve at the Entrance of Stylomastoid Foramen of Rabbit

Diffusion Route of Indian Ink Injected into the Facial Nerve at the Entrance of Stylomastoid Foramen of Rabbit

Diffusion Route of Indian Ink Injected into the Facial Nerve at the Entrance of Stylomastoid Foramen of Rabbit

Evaluation of Ototoxicity of Aminoglycoside Antibiotics injected into the Facial Nerve through the Stylomastoid Foramen of Rabbit

Evaluation of Ototoxicity of Aminoglycoside Antibiotics injected into the Facial Nerve through the Stylomastoid Foramen of Rabbit

Diffusion Route of Indian Ink Injected into the Facial Nerve at the Entrance of Stylomastoid Foramen of Rabbit

Diffusion Route of Indian Ink Injected into the Facial Nerve at the Entrance of Stylomastoid Foramen of Rabbit

メニエール病の反復性めまいに対する免疫アレルギー的考察

The reality of allergic endolymphatic hydrops as a cause of recurrent episodes of Meniere's disease was suggested from the results of the following studies: 1) Clinical studiesa) The skin test using 34 sorts of food antigen extracts and the glycerol test were performed on 23 patients with Meniere's disease. The rate of positive glycerol test was higher in the group with the positive skin reaction than in the negative group (p=0.05).b) In some patients, whose episodes were provoked by the challenge-feeding test, improvement in hearing was produced after Portmann's endolymphatic operation. 2) Experimental studiesa) Labyrinthine reactions were produced when challenged with the antigen through the left foramen stylomastoideum in 4 groups of rabbits as follows: (A) rabbits sensitized by hen's serum, (B) control rabbits, (C) rabbits inoculated with BCG vaccine and (D) control rabbits. Among these 4 groups, the positional nystagmus observed in group A bore a striking resemblance to that of Meniere's attack. The electrocochleograph of group A showed a pattern of cochlear impairment and a histological study revealed endolymphatic hydrops in the ear on the challenged side. This endolymphatic hydrops was not found in the other groups. From these findings, endolymphatic hydrops does not appear to be induced by cell-mediated immunity, but by humoral immunity.b) To determine the place of antigen-antibody reaction, the labyrinths of guinea pigs sensitized by horseradish peroxidase (HRP) were investigated by electronmicroscopy after challenge with this antigen through the perilymphatic space. Particles of HRP could pass through the Reissner's membrane by intracellular transportation and clung to the surface of dark cells in the stria vascularis. These findings were not observed in the control study and suggest that hyper-permeability of the Reissner's membrane and hypersecretion of the stria vascularis induced by the antigen-antibody reaction are probable causes of endolymphatic hydrops.

Anatomy of the temporal bone in early anthropoids, with remarks on the problem of anthropoid origins

AbstractNew and previously undescribed specimens of the petrous, squamous, and tympanic parts of the temporal bones of anthropoid primates from the Oligocene of Egypt display a general morphological resemblance to the equivalent parts of Recent ceboid skulls. Like that of ceboids, the ectotympanic bone of Fayum anthropoids is a simple anulus, fused to the squamosal at both its extremities. The petrosal's bullar contribution appears to bear transverse septa running laterally from promontory to ectotympanic; similar septa are seen in callitrichids and some prosimians. The definitive stylomastoid foramen is in a position characteristic for ceboids but not found among adult catarrhines. As far as can currently be determined, pneumatization of the petrous and squamous temporal is specifically anthropoid‐like in pattern and extent, but exhibits no special resemblances to that found in any particular anthropoid taxon. On the other hand, Fayum anthropoids appear to resemble other catarrhines and to differ from most extant ceboids in lacking a vascular canal leading from the subarcuate fossa to the sigmoid venous sinus. Vascular impressions on a squamosal fragment tentatively assigned to Aegyptopithecus zeuxis show that the petrosquamous and cranio‐orbital venous sinuses were persistently large, as in prosimians. A squamosal fragment previously attributed to Apidium phiomense, and adduced as evidence for a lemuriform ancestry of Anthropoidea, is probably that of a hyaenodontid creodont. It is certainly not that of a primate. The ceboid like morphology of the early catarrhine ear region is probably primitive for anthropoids, and in any case it does not argue for an Old World origin of ceboids–but it emphatically suggests that Anthropoidea is a strictly monophyletic taxon.

Percutaneous radiofrequency facial nerve coagulation in the management of facial spasm.

The authors have developed a fluoroscopy-assisted technique of percutaneous radiofrequency facial nerve coagulation at or near the stylomastoid foramen for management of facial spasm. The details of the procedure and the operative results in the initial series of 27 cases of facial spasm are described. The series included six men and 21 women, aged from 16 to 73 years. Twenty-four patients had classical, intractable, persistent hemifacial spasm, one had an unusual bilateral facial spasm, and one a postparalytic facial spasm. The age of onset varied from 16 years to 70 years. The duration of the symptoms ranged from 3 months to 11 years. Ten patients had undergone previous blunt-needle compression of the facial nerve from one to 10 times. The operative results in the 27 patients have so far been excellent. The longest follow-up has been 1 1/2 years. Although partial facial weakness was present in 60% of the cases, it invariably disappeared within 1 to 4 months. Only three patients experienced recurrence of spasm. In two of them, recurrence followed low-temperature coagulation. The procedure is simple, easy to perform, and extremely effective. It can be performed under local anesthesia in the outpatient clinic.