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Anatomy and Physiology of Balance
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Nishchay Mehta, Andrew Forge, Jonathan Gale
The superior semicircular canal abuts the mastoid tegmen, with a corresponding intracranial projection called the arcuate eminence. The thin bone of the tegmen that separates the canal from the dura at this point can be less than 1 mm in diameter.
Anatomy of the Skull Base and Infratemporal Fossa
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
The superior surface of the petrous temporal bone contributes to part of the floor of the middle cranial fossa, a sharp ridge along its posterosuperior aspect, angled at 45 degrees, separating this from its near vertical posterior surface which borders the anterior aspect of the posterior cranial fossa. Several important landmarks can be found on this superior surface. Most laterally, just medial to its articulation with the squamous part of the temporal bone, the petrous part forms the roof of the epitympanum, the tegmen tympani. Running along the posterior aspect of the petrous ridge is found the groove for the superior petrosal sinus. Between the two, posteromedial to the tegmen tympani, a curved prominence - the arcuate eminence - is made by the underlying superior semicircular canal. Just anteromedial to this is found the hiatus and groove for the greater petrosal nerve, passing obliquely to the foramen lacerum; the groove for the lesser petrosal nerve lies just anterolateral to this en route to the foramen ovale. Towards the anteromedial aspect of the superior surface, the trigeminal impression houses the trigeminal ganglion.
The influence of the subarcuate artery in the superior semicircular canal dehiscence and its frequency on stillbirths: illustrative cases and systematic review
Published in Acta Oto-Laryngologica, 2018
Gabriela Pereira Bom Braga, Jack H. Noble, Eloisa Maria Mello Santiago Gebrim, Robert F. Labadie, Ricardo Ferreira Bento
The SSC resides under the floor of the MCF, and is often denoted by the presence of a prominence protruding into the floor, known as the arcuate eminence [4]. During development, the covering of the SSC grows from a diaphanous state to a robust trilaminar capsule between birth and 3 years of age [7]. And it protrudes into the middle fossa during gestation, which may lead to adhesion of the membranous labyrinth to dura-mater before complete ossification of the bony labyrinth [4,8]. The superior semicircular canal is the first one to develop, followed by the posterior and the lateral canal. The development of the membranous labyrinth and the ossification of the semicircular canals proceeds in the same order, therefore, the lateral canal is the last one to ossify but it is less affected by the dehiscence, which makes us think about another etiology that includes an extra element in addition to a failure to develop normal thickness of the bone overlying the superior canal [9].
Combined transmastoid/middle fossa approach for a petrous bone cholesteatoma: A case report and literature review
Published in Acta Oto-Laryngologica Case Reports, 2021
Kiyotaka Miyazato, Yohei Hokama, Hideki Nagamine, Akira Ganaha, Mikio Suzuki, Shogo Ishiuchi
A 14-year-old girl experienced frequent episodes of otitis media for more than six years since childhood. In July 2011, the patient was examined at a clinic with the chief complaint of hearing loss in the right ear. Pure tone audiometry confirmed conductive hearing loss in the right ear with scores of 55.0 and 10.0 dB in the right and left ears, respectively. Her VII, IX, X, and XI cranial nerve functions were intact. She was diagnosed with right congenital cholesteatoma and was referred to our hospital's otolaryngology department to which she was admitted for treatment associated with a neurosurgical procedure in October. Preoperatively, the patient was alert and oriented without any neurological abnormalities. Blood sampling revealed no abnormalities in the biochemistry, including the complete blood cell count. Head computed tomography (CT) (Figure 1(a,b)) showed decalcification of the superior semicircular canal bony wall adjacent to the soft tissue structures in the right petrous bone and thinning of the cochlear bone. Head magnetic resonance imaging (Figure 1(c)) showed high signal intensity with no contrast effects in the diffusion-weighted image. The petrous bone CT was performed with a 64-multidetector row CT scan (Aquilion ONE, Toshiba Medical System, Corp., Tokyo, Japan) at 0.5-mm interval. Cranial CT was performed with a 64 multidetector row CT scan (VCT, General Electric Healthcare, Japan) with a 5.0-mm interval. Running the workstation of a 3D image analysis system (Synapse Vincent, Fuji Film Co., Tokyo, Japan), any structure can be extracted from the acquired images [2]. The tumor, semicircular canals, cochlea, and facial canal were tracked and visualized using petrous bone CT. These visualized structures were integrated with the cranial CT. The positional relationship of these structures from any viewing direction was revealed by rotating and making the skull transparent. Surgical views of the transmastoid and middle fossa approach were created, and the information was provided to otolaryngologists and neurosurgeons. Fast imaging employing steady-state acquisition showed progression of the lesion into the upper region of the anterior semicircular canal and vicinity of the arcuate eminence. There were no abnormalities in the facial nerve, vestibular nerve, cochlea, or semicircular canal (Figure 1(c–f)).