RESUMO
The endocranial structures of the sebecid crocodylomorph Zulmasuchus querejazus (MHNC 6672) from the Lower Paleocene of Bolivia are described in this article. Using computed tomography scanning, the cranial endocast, associated nerves and arteries, endosseous labyrinths, and cranial pneumatization are reconstructed and compared with those of extant and fossil crocodylomorphs, representative of different ecomorphological adaptations. Z. querejazus exhibits an unusual flexure of the brain, pericerebral spines, semicircular canals with a narrow diameter, as well as enlarged pharyngotympanic sinuses. First, those structures allow to estimate the alert head posture and hearing capabilities of Zulmasuchus. Then, functional comparisons are proposed between this purportedly terrestrial taxon, semi-aquatic, and aquatic forms (extant crocodylians, thalattosuchians, and dyrosaurids). The narrow diameter of the semicircular canals but expanded morphology of the endosseous labyrinths and the enlarged pneumatization of the skull compared to other forms indeed tend to indicate a terrestrial lifestyle for Zulmasuchus. Our results highlight the need to gather new data, especially from altirostral forms in order to further our understanding of the evolution of endocranial structures in crocodylomorphs with different ecomorphological adaptations.
Assuntos
Evolução Biológica , Dinossauros/anatomia & histologia , Fósseis/anatomia & histologia , Canais Semicirculares/anatomia & histologia , Crânio/diagnóstico por imagem , Animais , Artérias/anatomia & histologia , Artérias/diagnóstico por imagem , Bolívia , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Vértebras Cervicais/anatomia & histologia , Vértebras Cervicais/diagnóstico por imagem , Nervos Cranianos/anatomia & histologia , Nervos Cranianos/diagnóstico por imagem , Cavidades Cranianas/anatomia & histologia , Cavidades Cranianas/diagnóstico por imagem , Dinossauros/fisiologia , Orelha Interna/anatomia & histologia , Orelha Interna/diagnóstico por imagem , Fósseis/diagnóstico por imagem , Audição , Estilo de Vida , Postura , Canais Semicirculares/diagnóstico por imagem , Crânio/anatomia & histologia , Crânio/irrigação sanguínea , Tomógrafos ComputadorizadosRESUMO
Abstract Introduction Sigmoid sinus (SS) variations have been classified variously in the literature. These classifications suffer from some form of shortcoming from a clinical point of view for their application. Objective We propose a clinically relevant classification of the SS in relation to the posterior semicircular canal (PSCC) and to the exposure of the presigmoid dural plate. The positioning of the SS was analyzed with reference to the volume of themastoid and to the level of mastoid pneumatization. Methods A total of 94 formalin-preserved human cadaveric temporal bones were microdissected to carry out a complete mastoidectomy. The SS, the presigmoid dural plate, and the PSCCwere exposed, and the position of the former was analyzed in relation to the latter two in order to classify the position of the SS into three grades. Results GradeI hadthebest exposureof the presigmoid dura andof the PSCC,while grade III had the poorest exposure of the presigmoid dura and of the PSCC. Grade I SS was associated with good pneumatization and highermastoid volumescompared with grades II and III. Conclusions The SS exhibits considerable anatomic variability. A favorable positioning of the SS is associated with a large mastoid volume and pneumatization. A careful preoperative study of the imaging may help in understanding the positioning of the SS and the safety of various transmastoid approaches.
Assuntos
Humanos , Osso Temporal/anatomia & histologia , Processo Mastoide/anatomia & histologia , Cadáver , Canais Semicirculares/anatomia & histologia , Dissecação , MastoidectomiaRESUMO
In this study, we describe a natural endocranial cast included in a partially preserved medium-sized skull of the Upper Cretaceous South American snake Dinilysia patagonica. The endocast is composed of sedimentary filling of the cranial cavity in which the posterior brain, the vessels, the cranial nerves, and the inner ear surrounded by delicate semicircular canals, are represented. It is simple in form, with little differentiation between the three main areas (Forebrain, Midbrain, and Hindbrain), and without flexures. The nervous system is well preserved. The posterior brain surface is smooth, except for two small prominences that make up the cerebellum. A large inner ear is preserved on the right side; it consists of a voluminous central mass, the vestibule, which occupies most of the space defined by the three semicircular canals. In particular, the lateral semicircular canal is very close to the vestibule. This characteristic, in combination with the medium to large body size of Dinilysia, its large skull and dorsally exposed orbits, and vertebrae bearing a rather high neural spine on a depressed neural arch, suggests that this snake would have had a semifossorial lifestyle. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:9-20, 2018. © 2017 Wiley Periodicals, Inc.
Assuntos
Evolução Biológica , Fósseis/anatomia & histologia , Crânio/anatomia & histologia , Serpentes/anatomia & histologia , Animais , Argentina , Tronco Encefálico/anatomia & histologia , Prosencéfalo/anatomia & histologia , Canais Semicirculares/anatomia & histologia , Coluna Vertebral/anatomia & histologia , Vestíbulo do Labirinto/anatomia & histologiaRESUMO
Here we present the most detailed morphological study of the auditory region of a tremarctinae bear, Arctotherium tarijense Ameghino. In addition, we provide new anatomical information of the Tremarctinae inner ear, such as coplanarity and deviation from orthogonality of the semicircular canals, as an approach to infer the head movements which encountered the extinct forms in locomotion. Based on morphological comparisons, A. tarijense exhibits the following particular features: the cavum tympani presents the highest relative volume compared with other ursids; the processus paraoccipitalis has a foramen that is absent in other tremarctines; there is only one (ventral) recess in the anterior region of the cavum tympani; and the recessus epytimpanicus is the smallest for all ursids studied. In relation to the inner ear, A. tarijense shows the lowest values of orthogonality deviation and highest scores of locomotor agility. Based on this, is possible to make a preliminary proposal that this species had a relative high vestibular sensibility and therefore a better ability to explore different kind of habitats. However, this hypothesis might be contrasted among bears taking into account the orientation of each semicircular canal in a phylogenetic framework.
Assuntos
Extinção Biológica , Canais Semicirculares/anatomia & histologia , Ursidae/anatomia & histologia , Animais , Movimentos da Cabeça/fisiologia , Locomoção/fisiologia , Filogenia , Canais Semicirculares/fisiologia , América do Sul , Ursidae/fisiologiaRESUMO
OBJECTIVE: Evaluate the feasibility of an adequate exposure with anatomical preservation of labyrinth structures through retrosigmoid transmeatal approach (RSA) in surgeries for resection of acoustic neuromas/vestibular schwannomas (VS). METHOD: Thirty patients underwent surgical resection and were preoperatively evaluated with fine slice high definition CT scans and 3D-MRI volumetric reconstructions. Extension of internal auditory canal (IAC) opening during surgery was measured using 3 mm right-angle calibrated hook and neuronavigation parameters. Postoperatively, the extension of IAC opening and integrity of the labyrinth were confirmed through preoperatively images procedures. RESULTS: The preoperative length of IACs varied between 7.8 and 12.0 mm (mean 9.3 mm, SD 0.98, 95%CI 8.9 to 9.6, and median 9.0 mm). Postoperative images demonstrated adequate opening of the IAC and semicircular channels integrity. CONCLUSION: A complete drilling of the posterior wall of IAC through the RSA is feasible and allows direct visualization of the IAC-fundus without damaging the semicircular canals.
Assuntos
Orelha Interna/cirurgia , Neuroma Acústico/cirurgia , Tratamentos com Preservação do Órgão/métodos , Canais Semicirculares/anatomia & histologia , Estudos de Viabilidade , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Microcirurgia/métodos , Pessoa de Meia-Idade , Neuroma Acústico/patologia , Neuronavegação/métodos , Procedimentos Cirúrgicos Otológicos/métodos , Período Pós-Operatório , Estudos Prospectivos , Reprodutibilidade dos Testes , Canais Semicirculares/cirurgia , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento , Carga TumoralRESUMO
Objective Evaluate the feasibility of an adequate exposure with anatomical preservation of labyrinth structures through retrosigmoid transmeatal approach (RSA) in surgeries for resection of acoustic neuromas/vestibular schwannomas (VS). Method Thirty patients underwent surgical resection and were preoperatively evaluated with fine slice high definition CT scans and 3D-MRI volumetric reconstructions. Extension of internal auditory canal (IAC) opening during surgery was measured using 3 mm right-angle calibrated hook and neuronavigation parameters. Postoperatively, the extension of IAC opening and integrity of the labyrinth were confirmed through preoperatively images procedures. Results The preoperative length of IACs varied between 7.8 and 12.0 mm (mean 9.3 mm, SD 0.98, 95%CI 8.9 to 9.6, and median 9.0 mm). Postoperative images demonstrated adequate opening of the IAC and semicircular channels integrity. Conclusion A complete drilling of the posterior wall of IAC through the RSA is feasible and allows direct visualization of the IAC-fundus without damaging the semicircular canals. .
Objetivo Avaliar a possibilidade de exposição adequada preservando anatomia das estruturas labirínticas pelo acesso retrosigmóide-transmeatal (RSA) nas ressecções de schwannomas do vestibular (VS). Método Trinta pacientes foram submetidos à ressecção cirúrgica e avaliados no pré-operatório com tomografias de alta definição e reconstruções de ressonância magnética 3D. A extensão da abertura do conduto auditivo interno (CAI) foi medida e confirmada com parâmetros de neuronavegação. No pós-operatório, a extensão da abertura e a integridade do labirinto foram confirmadas por imagens de tomografia computadorizada. Resultados A extensão do CAI no pré-operatório apresentou variação de 7,8-12 mm (média 9,3 mm, DP 0,98, IC95% de 8,9-9,6 e mediana 9 mm). Imagens pós-operatórias demonstraram abertura adequada do IAC e integridade dos canais semicirculares. Conclusão A abertura completa da parede posterior do CAI pelo RSA é possível e permite a visualização direta do fundo do conduto sem prejudicar os canais semicirculares. .
Assuntos
Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Orelha Interna/cirurgia , Neuroma Acústico/cirurgia , Tratamentos com Preservação do Órgão/métodos , Canais Semicirculares/anatomia & histologia , Estudos de Viabilidade , Imageamento por Ressonância Magnética/métodos , Microcirurgia/métodos , Neuroma Acústico/patologia , Neuronavegação/métodos , Procedimentos Cirúrgicos Otológicos/métodos , Período Pós-Operatório , Estudos Prospectivos , Reprodutibilidade dos Testes , Canais Semicirculares/cirurgia , Resultado do Tratamento , Carga Tumoral , Tomografia Computadorizada por Raios X/métodosRESUMO
El objetivo fue estudiar las peculiaridades en la morfología apical del canal semicircular superior, a nivel de la eminencia arcuata con la finalidad de obtener conclusiones aplicativas. Se estudiaron 48 cabezas de cadáveres humanos (96 huesos temporales), con la intención de identificar la presencia de adelgazamiento o dehiscencia del canal semicircular superior, así como la existencia de surcos vasculares de la eminencia acuata que, discurriendo sobre el techo del canal, pudieran afectar a su integridad anatómica. El estudio incluye un análisis histológico (Tricrómico de Martins) y radiológico (Tomografía Computarizada) de los hallazgos positivos (dehiscencias y adelgazamientos), así como estudio tomográfico de los canales con surcos vasculares visibles. En un caso (1,04 por ciento hemos observado cómo el canal presentaba un defecto óseo completo (dehiscencia), en tres (3,12 por ciento) el canal presentaba una pared muy delgada cuyo grosor no excedía de 0,2 mm. En 12 casos (12,5 por ciento) la eminencia arcuata estaba recorrida por surcos por el que discurrían vasos colaterales meníngeos, que determinaron una concavidad entre 0,1 y 0,2 mm, mientras que el grosor medio de dicha pared en estos casos fue de 1,2 mm. De las tres peculiaridades estudiadas, la falta de cobertura ósea es la que produce el síndrome de dehiscencia del canal semicircular superior. Los canales que presentaban una cubierta adelgazada pueden estar predispuestos a una rotura y por lo tanto causar patología en el canal. En cambio la presencia de surcos vasculares que recorren la superficie apical del canal, no parece tener consecuencias al disminuir minimamente su grosor...
The aim was to study the peculiarities in apical morphology of the superior semicircular canal are studied at level of the arcuate eminence to obtain application conclusions. We have studied 48 heads from human cadavers (96 temporal bones), with the intention of identifying the presence of thinning or dehiscence in the superior semicircular canal, as well as the existence of vascular sulci of the arcuate eminence, which, traveling along the roof of the canal, may affect its anatomical integrity. The study includes a histological (Martin's Trichome method) and a radiological analysis (Computerized Tomography) of the findings (dehiscences and thinnings), and as well as tomographic study of the canals with visible vascular sulci. In one case (1.04 percent we have observed how the canal presented a complete bone defect (dehiscence), in three (3.12 percent), presented a very thin wall, which did not exceed 0.2 mm thick. In 12 cases (12.5 percent) sulci covered the arcuate eminence through which meningeal collateral vessels ran, which determined a concavity of between 0.1 and 0.2 mm, whilst the average thickness of this wall in these cases was 1.2 mm. Of the peculiarities studied, the lack of bone coverage is what produces the dehiscence syndrome of the superior semicircular canal. The canals that had a reduced coverage may be predisposed to breakage and therefore cause pathology in them. On the other hand, the presence of vascular sulci that ran along the apical surface of the canal seems to have no consequences to decrease their thickness...
Assuntos
Humanos , Canais Semicirculares/anatomia & histologia , Canais Semicirculares/anormalidades , Cadáver , Canais Semicirculares , Osso Temporal , Tomografia Computadorizada por Raios XRESUMO
UNLABELLED: Knowledge of the anatomy and physiology of the semicircular canals and their central pathways is essential for the diagnosis of vestibular pathology. This 3 dimensional (3D) scheme of the Semicircular Canals (SSCC) is a teaching tool and a useful reference guide for rapid consultation. MATERIAL AND METHODS: A multicolored cardboard model is accompanied by a user manual which provides a thorough description of the tool for the most common vestibular diseases. RESULTS: Although results cannot be quantitatively assessed, the model has been well received at several Latin American scientific conferences. The model is often understood with verbal instruction only; nevertheless, a printed user manual is included. CONCLUSIONS: This 3 dimensional (3D) model of the Semicircular Canals (SSCC) is a practical, low cost tool for use in private and academic settings.
Assuntos
Imageamento Tridimensional , Otolaringologia/educação , Canais Semicirculares/anatomia & histologia , Materiais de Ensino , HumanosRESUMO
Knowledge of the anatomy and physiology of the semicircular canals and their central pathways is essential for the diagnosis of vestibular pathology. This 3 dimensional (3D) scheme of the Semicircular Canals (SSCC) is a teaching tool and a useful reference guide for rapid consultation. MATERIAL AND METHODS: A multicolored cardboard model is accompanied by a user manual which provides a thorough description of the tool for the most common vestibular diseases. RESULTS: Although results cannot be quantitatively assessed, the model has been well received at several Latin American scientific conferences. The model is often understood with verbal instruction only; nevertheless, a printed user manual is included. CONCLUSIONS: This 3 dimensional (3D) model of the Semicircular Canals (SSCC) is a practical, low cost tool for use in private and academic settings.
A identificação de determinadas afecções vestibulares exige conhecimento prévio sobre anatomia e fisiologia dos canais semicirculares (CSC) e de suas conexões centrais, que apresentam complexidade anatômica tridimensional e funcional. OBJETIVO: Propor um modelo anatômico e funcional dos CSC, em 3 dimensões (3D), para servir como uma ferramenta didática e um guia útil de consulta rápida. MATERIAL E MÉTODOS: O modelo é projetado em cartão, com impressão em cores diferentes, acompanhados de um texto explicativo de 22 folhas, que detalha sua descrição topográfica, descritiva e sua utilização com base em exemplos das doenças vestibulares mais frequentes. RESULTADOS: Embora os resultados não possam ser avaliados numericamente, este modelo já foi compreendido por diversos especialistas e tem sido bastante utilizado por eles. Além disso, o produto deste trabalho já foi apresentado em diferentes eventos científicos latino-americanos com excelente aceitação. CONCLUSÃO: Trata-se de ferramenta útil e de baixo custo para o ensino, a prática clínica diária em otoneurologia.
Assuntos
Humanos , Imageamento Tridimensional , Otolaringologia/educação , Canais Semicirculares/anatomia & histologia , Materiais de EnsinoRESUMO
We document the morphology of the bony labyrinth of Chilecebus carrascoensis, one of the best preserved early platyrrhines known, based on high resolution CT scanning and 3D digital reconstruction. The cochlea is low and conical in form, as in other anthropoids, but has only 2.5 spiral turns. When the allometric relationship with body mass is considered, cochlear size is similar to that in extant primates. The relative size of the semicircular canals, which is well within the range of other primates, indicates that Chilecebus carrascoensis was probably not as agile in its locomotion as other small-bodied platyrrhines such as Leontopithecus rosalia, Saguinus oedipus, and Callithrix jacchus, but it probably was not a suspensory acrobat or a slow climber. The proportion, shape, and orientation of the semicircular canals in Chilecebus carrascoensis also mirror that typically seen in extant primates. However, no single variable can be used for predicting the locomotor pattern in Chilecebus carrascoensis. Based on Principle Component Analysis (PCA) scores we calculated rescaled Euclidean distances for various taxa; primates with similar locomotor patterns tend to share shorter distances. Results for Chilecebus carrascoensis underscore its general resemblance to living quadrupedal primate taxa, but it is not positioned especially near any single living taxon.
Assuntos
Cóclea/anatomia & histologia , Orelha Interna/anatomia & histologia , Fósseis , Platirrinos/anatomia & histologia , Platirrinos/classificação , Canais Semicirculares/anatomia & histologia , Animais , Evolução Biológica , Osso e Ossos/anatomia & histologia , Chile , Extinção Biológica , Especiação Genética , Imageamento Tridimensional , Locomoção , Filogenia , Tomografia Computadorizada por Raios X , Vestíbulo do Labirinto/anatomia & histologiaRESUMO
We provide the first detailed description of the inner ear of a notoungulate, an extinct group of endemic South American placental mammals, based on a three-dimensional reconstruction extracted from CT imagery of a skull of Notostylops murinus. This description provides new anatomical data that should prove to be phylogenetically informative, an especially significant aspect of this research given that both the interrelationships of notoungulates and the position of Notoungulata within Placentalia are still unresolved. We also assess the locomotor agility of Notostylops based on measurements of the semicircular canals. This is the best available data on the locomotion of a notostylopid because significant postcranial remains for this group have not been described. The cochlea of Notostylops has 2.25 turns, and the stapedial ratio is 1.6. The stapedial ratio is one of the lowest recorded for a eutherian, which typically have ratios greater than 1.8. The fenestra cochleae is located posterior to the fenestra vestibuli, a condition previously only reported for some stem primates. The separation of the saccule and utricule of the vestibule is visible on the digital endocast of the bony labyrinth. The posterior arm of the LSC and the inferior arm of the PSC are confluent, but these do not form a secondary crus commune, and the phylogenetic or functional significance of this confluence is unclear at this time. Locomotor agility scores for Notostylops suggest a medium or 'average' degree of agility of motion compared to extant mammals. In terms of its locomotion, we tentatively predict that Notostylops was a generalized terrestrial mammal, with cursorial tendencies, based on its agility scores and the range of locomotor patterns inferred from postcranial analyses of other notoungulates.
Assuntos
Orelha Interna/anatomia & histologia , Mamíferos/anatomia & histologia , Filogenia , Animais , Evolução Biológica , Cóclea/anatomia & histologia , Extinção Biológica , Fósseis , Canais Semicirculares/anatomia & histologia , Crânio , América do Sul , Tomografia Computadorizada por Raios X , Vestíbulo do Labirinto/anatomia & histologiaRESUMO
OBJECTIVES: To define anatomic parameters indicating or limiting the use of anterior and retrofacial accesses to sinus tympani (ST). MATERIAL: Anatomic study (30 temporal bones). MAIN OUTCOME MEASURE: The profundity of the ST, the distance between the sigmoid sinus and facial nerve (SS-F), the distance from posterior semicircular canal to the facial nerve, and the capacity of adequate visualization of the ST. RESULTS: Sinus tympani depth was significantly smaller (Assuntos
Nervo Facial/anatomia & histologia
, Procedimentos Cirúrgicos Otológicos/métodos
, Osso Temporal/cirurgia
, Membrana Timpânica/anatomia & histologia
, Membrana Timpânica/cirurgia
, Humanos
, Canais Semicirculares/anatomia & histologia
, Canais Semicirculares/cirurgia
, Osso Temporal/anatomia & histologia
RESUMO
We studied the spatial relations of the semicircular canals (SCCs) and their cristae, by computer-aided three-dimensional reconstruction, a graphic method we developed. The angles between pairs of SCCs, between pairs of SCC cristae, and between a SCC and its crista were measured using histology sections of a normal temporal bone from a 14-year-old female. Angles between pairs of SCCs and pairs of cristae deviated 11.3 to 18.2 degrees and 4.8 to 18.0 degrees, respectively, from right angles and the long axis of each crista deviated 25.0 to 30.4 degrees from the line perpendicular to the plane of the corresponding SCC; thus none of these structures lies at a right angle to another. We believe these new anatomical findings will help in the clinical evaluation of SCC function.