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Snakes have distinct body plans that can be traced to the origin of the clade. It remains unresolved whether ancestral snakes were adapted to terrestrial environments as burrowers, or to marine environments as swimmers. Recently, new approaches have been used to infer fossorial and aquatic specialists in the early evolution of snakes, using virtual CT models of the ear of fossils. This chapter reviews variation in the osseous part of the ear of major snake lineages. Vestibules are relatively large in fossorial species and small in aquatic snakes. Using quantitative analyses of bony labyrinth geometry, it has been suggested that putative stem snakes, such as Dinilysia patagonica, were fossorial. Improvements to testing correlations between bony labyrinth morphology and ecology can be made in the refinement of quantitative approaches to capturing and analysing shape variations, as well as better classifications of ecology. Using inner and middle ear morphology to improve the accuracy and precision of inferences of the ecology of the ancestral snake will depend also upon robust, well-resolved phylogenies for extinct and extant taxa, and denser taxonomic and ecomorphological sampling.
Many late antique and medieval sources show that the Early Christian basilica of Saint Peter's had a baptistery, but it has left no physical traces. Early descriptions of the location of this inscription are particularly interesting. Until the fifteenth century, the inscription was not inside the basilica but outside, fixed on the external wall near the hillside. The idea that the baptistery of Saint Peter's was monumental and independent was developed some time ago by Gillian Mackie. Many observations seem to indicate that the baptistery of Saint Peter's was a monumental one. It remains certain that the place of the Vatican baptistery must be associated with the north transept where it was described from the sixth-century Gesta Liberii to Alfarano a thousand years later, but the exact place indicated on Alfarano's plan was probably only the vestibule of an external independent and monumental baptistery.
To establish a new magnetic resonance imaging scoring system for diagnosing endolymphatic hydrops.
Patients and methods:
A total of 214 ears of 107 patients were categorised into five groups: no symptoms, Ménière's disease, sudden deafness, delayed endolymphatic hydrops and other ear disorders. Gadolinium distribution within the labyrinth was scored separately and quantitatively by two radiologists. Multiple independent-sample non-parametric tests, Bayesian discriminant analysis, multivariate logistic regression and receiver operating characteristic curve analyses were performed.
Results:
The derived scoring model was highly accurate for diagnosing Ménière's disease and delayed endolymphatic hydrops. Two magnetic resonance imaging scoring methods for the perilymphatic space were proposed for the diagnosis of endolymphatic hydrops: a pre-1 value (a new variable that predicts individual probability) of more than 0.3982299, or a sum of all labyrinth component scores of less than 14.5.
Conclusion:
A convenient method is proposed which offers reliable radiological diagnostic criteria for Ménière's disease and delayed endolymphatic hydrops.
Cochlear implantation has been used to rehabilitate profoundly deafened adults for more than 25 years. However, surgical labyrinthectomy is often considered a contraindication to cochlear implantation, especially if there is a significant delay between the two procedures. As the role of cochlear implantation continues to expand, this idea requires reconsideration.
Case report:
A 59-year-old woman presented to our clinic after undergoing bilateral surgical labyrinthectomies for intractable Ménière's disease 21 years prior. Despite the significant time delay, she underwent cochlear implantation with a good audiological outcome and improved quality of life.
Conclusion:
Changes to the cochlea and vestibule following surgical labyrinthectomy include cochlear ossification and obliteration of the vestibule. These issues have been thought to limit the potential for cochlear implantation, especially when there is a significant delay between the two procedures. However, delayed cochlear implantation, even decades after labyrinthectomy, remains a viable treatment option which can benefit selected patients.
The influence of congenital cytomegalovirus infection on cochlear function has been well recognised; however, its impact on the vestibular system in infants has not been examined. The purpose of the present study was to evaluate vestibular function in a group of infants, using caloric stimulation tests and vestibular-evoked myogenic potential measurements.
Materials and methods:
Vestibular-evoked myogenic potentials and auditory brainstem responses were recorded and caloric stimulation was performed in 66 infants aged three months, comprising 40 healthy controls and 26 infants with congenital cytomegalovirus infection.
Results:
No reaction to caloric stimulation was elicited from 16 examined ears, no vestibular-evoked myogenic potentials were recorded from 12 ears, and profound sensorineural hearing loss was diagnosed in eight ears. Pathological results were observed predominantly in infants with symptoms of intrauterine congenital cytomegalovirus infection present at birth.
Conclusions:
In infants with clinical symptoms of congenital CMV infection present at birth, abnormal vestibular test results occurred more frequently than abnormal auditory brainstem response results. Vestibular organs should be routinely examined in individuals with congenital cytomegalovirus infection.
Traumatic luxation of the stapes into the vestibule is a rare entity, and the disease complicated with pneumolabyrinth is extremely rare. We report the case of a 72-year-old woman with pneumolabyrinth associated with a stapediovestibular dislocation. The patient presented with vertigo and nystagmus following penetrating trauma to the middle ear. High resolution computed tomography scans demonstrated air in the vestibule and dislocation of the stapes. Exploratory tympanotomy demonstrated oozing of the perilymph from the oval window and depression of the stapes into the vestibule. Pneumolabyrinth and stapes luxation detected by high resolution computed tomography should be predictive of a perilymphatic fistula.
To establish if the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of the vestibule, after the removal of vestibular schwannoma by a modified translabyrinthine approach, correlate with a successful outcome, defined as hearing preservation.
Materials and methods:
Our study group consisted of 16 patients with vestibular schwannoma. All patients' pre-operative hearing was graded as class one or two according to the Gardner–Robertson scale. On MRI scans, the schwannoma, including the intracanalicular segment, were less than 2 cm in size in all the patients. The intracanalicular portion involved the fundus of the internal auditory canal in seven patients. In the remaining nine patients, the schwannoma had spread to involve two-thirds of the meatus, sparing its lateral third. The state of the labyrinth, in particular the integrity of the vestibule, was evaluated by CT scans and MRI prior to and following surgery.
Results:
The schwannoma was completely removed in all patients. None showed any signs of persistence or tumoral relapse on the post-operative MRI. The final follow up showed that seven patients had maintained their hearing function (i.e. four patients with class one hearing and three with class two). The MRI vestibular signal on the T2-weighted images was well depicted only in patients with hearing preservation. Bony vestibular integrity was observed in the CT scans of all cases with hearing preservation, and also in three cases with failure of hearing preservation.
Conclusion:
Our results confirm that total isolation and maintenance of an anatomically intact vestibule, as depicted by MRI examination, is one of the fundamental factors for successful preservation of hearing function following modified translabyrinthine approach schwannoma removal.
Meningiomas account for approximately 18 to 19 per cent of all brain tumours. Although they can arise in numerous locations, meningiomas of the internal auditory canal (IAC) are rare. Most tumours that originate in the IAC are schwannomas of the Vilith cranial nerve (acoustic neuromas). We report a case of a meningioma which appears to originate from the IAC and extends into the vestibule. The clinical findings and the radiographical features of meningiomas of the IAC are similar to those of acoustic neuromas. Pre-operative differentiation between acoustic neuromas and meningiomas of the IAC may be difficult.
The planum semilunatum is located on the lateral side of the crista ampullaris of thesemicircular canal. With regard to the functions of the planum semilunatum, some researchers assume the existence of secretory activity based on the microstructural features observed in isotopic experiments. In the present study, in order to confirm the existence of an immunological mechanism in the ampulla of the semicircular canal, the distribution of immunoglobulins in the semi-circular canal of guinea pigs was investigated immunohistochemically. Positivity of IgG wasobserved in the constituent cells of the planum semilunatum or beneath the basement membrane ofthe cells.It is concluded that ample IgG, which is an important constituent of the body fluids, is collected within this region. The planum semilunatum containing such ample amounts of IgG might be involved in the immunological mechanism operating in the ampullar of the semicircular canal.
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