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Growth of the Ear Capsule
Published in D. Dixon Andrew, A.N. Hoyte David, Ronning Olli, Fundamentals of Craniofacial Growth, 2017
Kneiborg et al. (1993) made 3-dimensional CT scan models from a 1-month old female infant with Apert’s syndrome. There was marked widening and asymmetry of the skull base, with the petrous bones displaced more transversely to the midsagittal axis: about a 70° petrosagittal angle (compared with Ford’s 1956a angle of 45°). In this syndrome also, Suehiro and Sando (1979) noted a persistent, large subarcuate fossa connecting to the middle cranial fossa. Normally this fossa attains maximum size by 21 fetal weeks (Anson and Donaldson, 1973), and thereafter diminishes. Although variable in the adult, it is usually of small, often pinpoint size.
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 ear is derived from the ectoderm of the cephalic portion of the embryo, originating from one round vesicle during week 6 of gestation. The otocist cavity contains endolymph and the organ of Corti. Inner ear appears on the ninth week as the endolymphatic duct system including mesenchymal tissue into which an early vacuolated perilymphatic, forms the labyrinth system [1,2]. The cartilaginous optic capsule will form the labyrinth. On the 23rd week, the cochlea reaches its total size and periotic spaces are well-formed. On the eighth week the subarcuate artery (SAA) develops from a branch of the labyrinthine artery, but most frequently from the anterior inferior cerebellar artery, and its invagination towards the subarcuate fossa (SAF) causes the expansion of the semicircular canal [2,3]. This event delays the ossification process of the bone around the labyrinth, making the cartilage spongiotic on the canalicular division of the optic capsule, leading to a bony defect [2–4].