Human anatomy, including structure and development and practical considerations . e liorizontal—lie behind the vestibule and are perpendicular toone another (Fig. 1265). Their disposition is such that the planes of the three canalscorrespond with thesides of the corner of acube, ? suggestively re-calling the relations ofthe three cardinalplanes of the body—the sagittal, frontal andtransverse. Each canalpossesses at one end adilatation, called theosseus ampulla. Thesuperior canal (ca-nalis superior) lies farth-est front and in a nearlyvertical plane at rightangles to the long axisof the petrous
Human anatomy, including structure and development and practical considerations . e liorizontal—lie behind the vestibule and are perpendicular toone another (Fig. 1265). Their disposition is such that the planes of the three canalscorrespond with thesides of the corner of acube, ? suggestively re-calling the relations ofthe three cardinalplanes of the body—the sagittal, frontal andtransverse. Each canalpossesses at one end adilatation, called theosseus ampulla. Thesuperior canal (ca-nalis superior) lies farth-est front and in a nearlyvertical plane at rightangles to the long axisof the petrous portionof the temporal bone,whilst the plane of thelongest canal, the pos-terior (caoalis posterior) is parallel to it. The external ])ortion ofthe horizontal semicircular canal ft)rms a prominence on the inner wall of the middleear above the facial canal, while the upper part of the superior semicircular canalproduces the conspicuous elevation, the eminentia arcuata, seen on the superior Ampulla of _superior canal Ampulla of_horizontal canal Facial canal. Small end ofposterior canal Crus commune Small end oflorizontal canal .?\mpulla ofposterior canal Oval (vestibiilfwind( Lamina sjnra Round (cochlear Section of right bony labyrinth passing through plane of superior semicircularcanal ; posterior wall of vestibule is seen from before. < 4. THE INTERNAL 1513 surface of the petrous bone. The semicircular canals (jjjen into the posterior part ofthe vestibule by five apertures (Fig. 1267), the undilatecl ends of the superic^r andposterior canals joining to form a common limb (cms coiiiiminc). The horizontalcanal (caiiaiis lateralis) alone communicates with the \estibule by two distinct open-ings. Its ampulla is at its outer end and lies at the upper part of the vestibule abovethe oval winclow, from which it is separated by a groo\e corresponding^ to the facialcanal. Lying- above and close to this oj^ening is placed the ampullary end of thesuperior canal
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Keywords: ., bookauthormc, bookcentury1900, bookdecade1910, booksubjectanatomy
