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The petrosal and neighboring bones of the early Eocene palaeoryctid mammal Eoryctes melanus are described in tympanic and endocranial views based on CT scan data of the holotype. A second cranium of E. melanus has fragments of an osseous bulla, which have been interpreted as possibly formed by an independent entotympanic. The CT scans of the holotype reveal that the medial bullar wall is formed by an expanded rostral tympanic process of the petrosal, but the element(s) in the bullar floor remain unknown. The CT scans also allow for a comprehensive reconstruction of the cranial arterial and venous system. The arterial pattern differs from that in early eutherians by the absence of the arteria diploëtica magna and the bifurcation of the end branches of the stapedial artery dorsal to the tympanic roof. The venous pattern includes a large frontal diploic vein arising from the dorsal sagittal sinus on the midline and running through the frontal bone in a canal. Comparisons are made with other palaeoryctids, various Paleogene mammals (pantolestids, leptictids, apternodontids, apatemyids, and cimolestids) and the extant lipotyphlan Solenodon paradoxus. For the last taxon, the structure of the piriform fenestra and associated arteries is detailed. Cranial features support the monophyly of palaeoryctids and suggest possible lipotyphlan affinities.

The clinical and neuroimaging findings of a family with a variant ACTA2 gene (c351C > G), presenting with smooth muscle dysfunction in structures of neural crest derivation, are discussed. The combination of aortic abnormalities, patent ductus arteriosus, congenital mydriasis and distinctive cerebrovascular and brain morphological abnormalities characterise this disorder. Two sisters, heterozygous for the variant, and their mother, a mosaic, are presented. Brain parenchymal changes are detailed for the first time in a non-Arg179His variant. Radiological features of the petrous canal and external carotid are highlighted. We explore the potential underlying biological and embryological mechanisms. [ABSTRACT FROM AUTHOR]

Sea turtles have well developed lacrimal glands for their electrolyte homeostasis. In turtles, stapedial artery and palatine artery send branches to supply orbital region, but supply artery for lacrimal glands was not identified. Micro-CT scans showed dorsoventrally large lacrimal glands of sea turtle are supplied by both stapedial artery and palatine artery. The circulatory pattern in cranial region was reconstructed based on the micro-CT scans, showing that sea turtle has basically similar pattern with the common snapping turtle: stapedial artery supplies orbital region and mandibular artery is ramified from stapedial artery. We also investigate the foramen stapedio-temporalis in turtles using osteological specimens. The foramen stapedio-temporalis, where the stapedial artery passes through, has different size among four families of turtles. We compared the sum of cross sections of left and right foramen stapedio-temporalis since homeostasis of one individual is maintained by a pair of lacrimal glands. The size difference may reflect primarily the share of stapedial artery against palatine artery in cranial circulation pattern and blood supply of orbital regions. Our observations confirmed a significantly larger cross-section in the foramen stapedio-temporalis of sea turtles than other freshwater/terrestrial turtles. Since the circulatory pattern is shared, the size difference of foramen stapedio-temporalis reflects the amount of arterial blood supply to lacrimal glands. Therefore, the size of the foramen stapedio-temporalis may indicate marine adaptation of turtles and are applicable to both fossil and osteological specimens. [ABSTRACT FROM AUTHOR]

The petrosal and neighboring bones of the early Eocene palaeoryctid mammal Eoryctes melanus are described in tympanic and endocranial views based on CT scan data of the holotype. A second cranium of E. melanus has fragments of an osseous bulla, which have been interpreted as possibly formed by an independent entotympanic. The CT scans of the holotype reveal that the medial bullar wall is formed by an expanded rostral tympanic process of the petrosal, but the element(s) in the bullar floor remain unknown. The CT scans also allow for a comprehensive reconstruction of the cranial arterial and venous system. The arterial pattern differs from that in early eutherians by the absence of the arteria diploëtica magna and the bifurcation of the end branches of the stapedial artery dorsal to the tympanic roof. The venous pattern includes a large frontal diploic vein arising from the dorsal sagittal sinus on the midline and running through the frontal bone in a canal. Comparisons are made with other palaeoryctids, various Paleogene mammals (pantolestids, leptictids, apternodontids, apatemyids, and cimolestids) and the extant lipotyphlan Solenodon paradoxus. For the last taxon, the structure of the piriform fenestra and associated arteries is detailed. Cranial features support the monophyly of palaeoryctids and suggest possible lipotyphlan affinities. [ABSTRACT FROM AUTHOR]

The stapedial artery (SA) is an embryonic vessel connecting the internal carotid artery (ICA) to the branches of the future external carotid artery (ECA). It passes through the primordium of the stapes that progressively develops around the SA. Normally, SA disappears during the tenth week in utero. Approximately 0.4% of the population can have a persistent SA. It can persist as four types of embryological variations, of which the pharyngo-hyo-stapedial variant has been rarely described before. We reported a case of a 61-year-old woman presented with transient ischemic attacks (TIAs). Computed tomography angiography showed an unusual "duplicated" aspect of the left ICA. Digital subtraction angiography depicted a persistent pharyngo-hyo-stapedial artery with an atherosclerotic wall and was considered the cause of the TIAs. After failure of the antiplatelet therapy in preventing recurrent TIAs, stenting of the artery was planned and successfully performed. Patient was asymptomatic during 12-month follow-up. The pharyngo-hyo-stapedial artery is a very rare variation in which the SA is supplied by the inferior tympanic (rising from the ascending pharyngeal artery) and the hyoid artery (rising from the ICA). To our knowledge, this is a unique case of a pharyngo-hyo-stapedial artery in a patient presenting associated ischemic symptoms. Radiological and embryological findings are discussed. [ABSTRACT FROM AUTHOR]

Background: The mammalian middle ear comprises a chain of three ossicles—the malleus, incus, and stapes—each of which has a unique morphology for efficiently transmitting sound information. In particular, the stapes, which is attached to the inner ear, is stirrup‐shaped with a head and base connected by two crural arches, forming the stapedial foramen, through which the stapedial artery passes. However, how the stapes acquires this critical stirrup shape for association with the stapedial artery during development is not clear. Results: C‐X‐C motif chemokine ligand 12 (CXCL12) is a chemoattractant essential for cellular movement and angiogenesis. In Cxcl12−/− embryos, migration of neural crest cells into the prospective middle ear regions and their mesenchymal condensation to form the three ossicles proceed normally in correct alignment with each other and the inner ear. However, in the absence of CXCL12, the stapes loses its stirrup shape and instead exhibits a columnar shape lacking the crural arches and central hole. In addition, although the stapedial artery initially forms during early mesenchymal condensation of the stapes, it degenerates without CXCL12 function. Conclusion: CXCL12 plays an essential role in establishing the stirrup‐shaped architecture of the stapes, possibly by maintaining the stapedial foramen and stapedial artery throughout development. Key Findings: The stapes is a stirrup‐shaped ossicle with a central foramen through which the stapedial artery penetrates.Cxcl12 is expressed in the condensing mesenchyme that forms the stapedial anlagen.The stapedial artery and stapedial foramen fail to form in the absence of CXCL12.CXCL12 is required for establishing the stirrup shape during stapes development. [ABSTRACT FROM AUTHOR]

Deviations from normal embryologic development can manifest in different anatomical variants of the ophthalmic artery. We present a case of an infant treated for a high-flow dural arteriovenous fistula of the superior sagittal sinus, in whom an arterial circle involving the ophthalmic artery, the middle meningeal artery, the inferolateral trunk and a hypoplastic segment of the internal carotid artery was found. The embryologic development is briefly reviewed with emphasis on the possible genesis of this interesting constellation. [ABSTRACT FROM AUTHOR]

Objective: (1) Discuss the presentation and management of persistent stapedial artery (PSA) discovered incidentally during cholesteatoma surgery. (2) Review use of carbon dioxide (CO2) laser for treatment of PSA in the setting of chronic ear disease. Patients: Two consecutive patients with PSA and primary acquired cholesteatoma. Intervention(s): Tympanomastoidectomy using a canal wall reconstruction technique. Main Outcome Measure(s): Surgical healing, collateral damage to surrounding anatomy, and postoperative hearing. Results: Persistent stapedial artery was detected incidentally in 2 patients, manifesting with heavy pulsatile bleeding arising during dissection of mesotympanic cholesteatoma. Preoperative computed tomography scans demonstrated absent foramen spinosum but no other aberrant vascular anatomy. Using CO2 laser, the PSAs were ablated and controlled, allowing complete resection of cholesteatoma and successful completion of the procedure. In both patients, surrounding anatomical structures suffered no iatrogenic injury. Postoperatively, no significant complications occurred. To date, neither patient has demonstrated evidence of recidivistic cholesteatoma. Conclusions: A CO2 laser can be useful for managing a PSA in the setting of chronic ear disease. [ABSTRACT FROM AUTHOR]

Primate species typically differ from other mammals in having bony canals that enclose the branches of the internal carotid artery (ICA) as they pass through the middle ear. The presence and relative size of these canals varies among major primate clades. As a result, differences in the anatomy of the canals for the promontorial and stapedial branches of the ICA have been cited as evidence of either haplorhine or strepsirrhine affinities among otherwise enigmatic early fossil euprimates. Here we use micro X-ray computed tomography to compile the largest quantitative dataset on ICA canal sizes. The data suggest greater variation of the ICA canals within some groups than has been previously appreciated. For example, Lepilemur and Avahi differ from most other lemuriforms in having a larger promontorial canal than stapedial canal. Furthermore, various lemurids are intraspecifically variable in relative canal size, with the promontorial canal being larger than the stapedial canal in some individuals but not others. In species where the promontorial artery supplies the brain with blood, the size of the promontorial canal is significantly correlated with endocranial volume (ECV). Among species with alternate routes of encephalic blood supply, the promontorial canal is highly reduced relative to ECV, and correlated with both ECV and cranium size. Ancestral state reconstructions incorporating data from fossils suggest that the last common ancestor of living primates had promontorial and stapedial canals that were similar to each other in size and large relative to ECV. We conclude that the plesiomorphic condition for crown primates is to have a patent promontorial artery supplying the brain and a patent stapedial artery for various non-encephalic structures. This inferred ancestral condition is exhibited by treeshrews and most early fossil euprimates, while extant primates exhibit reduction in one canal or another. The only early fossils deviating from this plesiomorphic condition are Adapis parisiensis with a reduced promontorial canal, and Rooneyia and Mahgarita with reduced stapedial canals. [ABSTRACT FROM AUTHOR]

Objective:The results of a recently published micro-CT study suggested a correlation of the distance between long incus process and stapes footplate and the required prosthesis length in malleostapedotomy. The goal of this study was to test the reliability of that assumption.Methods:Rectangular and bent prostheses were tested in 11 cadaveric human temporal bone specimens; 1 of them showed a stapedial artery. Prosthesis length was calculated based on the distance between long incus process and stapes footplate. The rate of acceptable prosthesis insertion into the vestibule was investigated.Results:In both prostheses designs, the insertion depth into the vestibule did not exceed 1.0 mm. Two prostheses did not pass the footplate level in bent prostheses (18%) and 1 in rectangular prostheses (9%).Conclusion:A rough estimation of the required prosthesis length in malleostapedotomy seems possible if the distance between long incus process and stapes footplate is known and a design-dependent equation exists. [ABSTRACT FROM AUTHOR]

The stapedial artery is an embryonic artery which disappears during the tenth week in utero, in human species. During its short life, this artery shapes the stapes and transforms the middle meningeal artery from the internal carotid artery to a branch of the external carotid system. Nevertheless, a persistent stapedial artery is seen in 0.2–4.8 per thousand of human adults. This persistence is usually asymptomatic but can sometimes cause pulsatile tinnitus or conductive hearing loss. Despite the risk of facial palsy, hearing loss and even hemiplegia argued by several authors, some surgeons have succeeded in coagulation without side effects. Reviewing the literature, we seek to enlighten the actual knowledge about the persistent stapedial artery to evaluate the risk to coagulate it. Embryologic studies explain the four types of persistent stapedial arteries: the hyoido-stapedial artery, the pharyngo-stapedial artery, the pharyngo-hyo-stapedial artery and aberrant internal carotid with persistent stapedial artery. Phylogenetic studies show that the stapedial artery persists in adulthood in many vertebrates. Its disappearance is therefore either a random effect or an adaptative convergence. This adaptation could be partially linked to the negative allometry of the stapes. Practically, the risk to coagulate a stapedial artery seems limited thanks to anastomoses, for example with the stylomastoid artery. The risk of hemiplegia reported is in fact an extrapolation of variation in rats’ embryos. A persistent stapedial artery can therefore reasonably be coagulated, with special attention to the facial nerve, because the facial canal is always dehiscent where the artery penetrates. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis The murine model has been used extensively to model and study human deafness. Technical difficulty in the surgical approach due to the small size of the tympanic bulla and a robust stapedial artery has limited its application for studies of cochlear implantation and electrical stimulation. We describe a minimally traumatic, stapedial artery-sparing approach to the round window that may be used to access the mouse cochlea for acute or chronic studies of implantation and stimulation. Study Design Animal model. Methods Fifteen C57BL6J mice were used to validate this approach. Auditory brainstem response threshold and distortion product otoacoustic emissions were obtained preoperatively and 2 weeks postoperatively to determine hearing preservation results. Results The approach provided excellent exposure for round-window implantation. Substantial hearing was preserved in all animals with a mean postimplantation auditory brainstem response threshold increase of 27.8 dB. Otoacoustic emissions were lost in subjects with the largest threshold shifts. Conclusions Residual hearing after cochlear implantation is a determinant of success both with standard cochlear implant electrodes and with electrodes designed to optimize hearing preservation. Here, we have preserved usable hearing after implantation of C57BL6J mice, an endogenous model of human presbycusia. The murine model may become a powerful tool to assay the effects of cochlear intervention in different genetic backgrounds. Laryngoscope, 123:E109-E115, 2013 [ABSTRACT FROM AUTHOR]

Sea turtles have well developed lacrimal glands for their electrolyte homeostasis. In turtles, stapedial artery and palatine artery send branches to supply orbital region, but supply artery for lacrimal glands was not identified. Micro-CT scans showed dorsoventrally large lacrimal glands of sea turtle are supplied by both stapedial artery and palatine artery. The circulatory pattern in cranial region was reconstructed based on the micro-CT scans, showing that sea turtle has basically similar pattern with the common snapping turtle: stapedial artery supplies orbital region and mandibular artery is ramified from stapedial artery. We also investigate the foramen stapedio-temporalis in turtles using osteological specimens. The foramen stapedio-temporalis, where the stapedial artery passes through, has different size among four families of turtles. We compared the sum of cross sections of left and right foramen stapedio-temporalis since homeostasis of one individual is maintained by a pair of lacrimal glands. The size difference may reflect primarily the share of stapedial artery against palatine artery in cranial circulation pattern and blood supply of orbital regions. Our observations confirmed a significantly larger cross-section in the foramen stapedio-temporalis of sea turtles than other freshwater/terrestrial turtles. Since the circulatory pattern is shared, the size difference of foramen stapedio-temporalis reflects the amount of arterial blood supply to lacrimal glands. Therefore, the size of the foramen stapedio-temporalis may indicate marine adaptation of turtles and are applicable to both fossil and osteological specimens.

The magnetic resonance imaging (MRI) in a female patient who presented with headache and hearing loss revealed aberrant course of the petrous segment of internal carotid artery (ICA). Computed tomography (CT) of the temporal bone done to confirm the findings of MRI revealed aberrant course of right ICA, a persistent stapedial artery (PSA) and absent foramen spinosum on the same side. In addition patient had a cystic cochleovestibular anomaly on the right side with both conditions may probably be contributing to her hearing loss. [ABSTRACT FROM AUTHOR]

Conclusions . The increase in cochlear blood flow (CBF) after administration of prostaglandin E 1 (PGE 1 ) to the round window depends on increased blood flow through the anterior inferior cerebellar artery (AICA). Objectives . To evaluate the response of CBF to PGE 1 applied topically to the round window, and to investigate the origin of blood flow changes after this topical application. Material and methods . The response of CBF to topically applied PGE 1 was measured by placing the tip of a laser Doppler probe on the bony wall of the basal turn of the cochlea after the middle ear mucosa over the cochlea had been removed in guinea pigs and rats. In rats, the CBF response to PGE 1 administration was investigated after occlusion of the AICA or stapedial artery. Results . CBF increased following PGE 1 administration in both guinea pigs and rats. In rats, CBF increased from 100% to 132%±10% (mean±SD) after the topical application of 0.5?µl of a 0.014% PGE 1 solution. CBF decreased after occlusion of the AICA or stapedial artery but did not increase after PGE 1 administration during occlusion of the AICA. The CBF response to PGE 1 administration was similar before and after occlusion of the stapedial artery. [ABSTRACT FROM AUTHOR]

Summary: A middle meningeal artery arising from the internal carotid artery was found in the right half of the head of an 85-year-old male cadaver during student dissection practice. It arose from the lateral aspect of the internal carotid artery in the carotid canal, arrived at the foramen lacerum after running forward. It then ran backward under the trigeminal ganglion and took the usual course after passing its posterior margin. On one hand, the maxillary artery did not issue the middle meningeal artery, gave off only a small twig supplying the lateral pterygoid muscle at the corresponding position. It was corroborated by the fact that the foramen spinosum was absent in this example. During usual development, the middle meningeal artery primarily springs from the supraorbital branch of the stapedial artery that arises from the dorsal part of the second branchial artery. Later, by the formation of the external carotid artery connecting with the common trunk of the infraorbital and mandibular branches (maxillomandibular division) of the stapedial artery and by the atrophy of the proximal part of it, the middle meningeal artery is finally supplied by the external carotid artery. But in this example, it is supposed that the middle meningeal artery arose from a more distal position of the internal carotid artery owing to the persistence of the anastomosis between the dorsal part of the first branchial artery and the supraorbital branch and the interruption of the connection between the supraorbital branch and maxillomandibular division of the stapedial artery. [Copyright &y& Elsevier]

Abstract: The laboratory rat has been used extensively in auditory research but has had limited use in cochlear implant related research due mainly to the surgically restricted access to the scala tympani. We have developed a new surgical method for cochlear implantation in rats. The key to this protocol was cauterizing the stapedial artery (SA) and making a small cochleostomy near the round window in order to enlarge the surgical access to the scala tympani. Five normal hearing Hooded Wistar rats were used to investigate the effect of cauterizing the SA on hearing and auditory nerve survival. Results showed that cauterizing the SA was surgically feasible, afforded excellent exposure of the round window niche for cochleostomy, and did not adversely affect acoustic thresholds measured electrophysiologically. Moreover, there was no difference in spiral ganglion cell densities for any cochlear turn when compared with the contralateral control ears. Three deafened rats were subsequently implanted with a scala tympani electrode array using this new surgical approach. Electrically evoked auditory brainstem responses using bipolar stimulation, and subsequent cochlear histopathology demonstrated that cochlear implantation using a custom-made rat electrode array was safe and effective. The surgical approach presented in this paper presents a safe and effective procedure for acute or chronic cochlear implantation in the rat model. [Copyright &y& Elsevier]

This study was performed to elucidate the contribution of the stapedial artery (SA) – which has been considered to be independent of the vertebrobasilar system – to blood flow in the ear by observing ear blood flow in Sprague–Dawley rats. A laser-Doppler (LD) probe was positioned on the bony wall of the cochlear basal turn after removal of the middle ear mucosa. The LD output was measured while either or both the SA and the anterior inferior cerebellar artery (AICA) were occluded. The LD output decreased to 70.6±2.5% (mean±S.D.) of the baseline value following SA occlusion, and to 58.0±7.8% following AICA occlusion in 12 animals. The rebound phenomenon of blood flow, which is a type of autoregulation, was only observed after releasing AICA occlusion. Simultaneous occlusion of the SA and AICA decreased the LD output to 27.0±5.5% of the baseline value. The role of the contribution of the SA and AICA to the LD output is discussed. [Copyright &y& Elsevier]

The variability of the origin of the anterior tympanic artery was investigated in 104 individuals of both sexes. A surprising laterality was found: thus, while the left anterior tympanic artery originated as a singular vessel from either the maxillary or the superficial temporal artery with almost equal frequencies (44.7 and 45.9%, respectively), the right anterior tympanic artery predominantly branched off from the maxillary artery (77.8% of cases). Besides the origin from either the maxillary artery or the superficial temporal artery, also anterior tympanic arteries branching off from the external carotid artery were found to occur (4% on the left and 1% on the right side). Although in the majority of individuals, a singular anterior tympanic artery occurred within the infratemporal fossa, duplications of the anterior tympanic artery were found to be present: in one case on the right and in 8 cases on their left side. In 1 female individual, a triplet of left anterior tympanic arteries was found to supply the tympanic cavity. Also in these cases, the anterior tympanic artery arose from either the external carotid, the superficial temporal or the maxillary artery. In singular cases, even several other branches of the maxillary artery, viz. the deep auricular, middle, and accessory meningeal, as well as the posterior deep temporal, inferior alveolar and masseteric arteries were found to form common trunks with the anterior tympanic artery.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

An 8-year-old child was examined because of conductive hearing loss with a retrotympanic mass on otoscopy. CT and MR angiography showed a large inferior tympanic artery traversing the hypotympanum and joining a thin, irregular internal carotid artery with a normal middle meningeal artery. These investigations, coupled with knowledge of the embryological development allowed a diagnosis of a complex vascular anomaly in the middle ear and avoided potential surgical complications. [ABSTRACT FROM AUTHOR]