Morphometric Comparison of Endolymphatic and Perilymphatic Spaces in Human Temporal Bones

Abstract

To measure the endolymphatic and perilymphatic spaces, we used human temporal bones (horizontal serial sections) under two selection criteria: absence of otological pathology, and absence of artifact in the membranous labyrinth (boundary between endolymphatic and perilymphatic spaces) maintaining an intact structural integrity. Under magnified projection, the area of scala tympani, scala vestibuli, scala media, vestibular endolymphatic space, and vestibular perilymphatic space were measured separately, using a microcomputer digitizing tablet. Three repeated measurements were obtained and averaged. The mean total labyrinthine fluid space was 204.5 mm3; the mean total endolymphatic space was 38.1 mm3 and mean total perilymphatic space 166.4 mm3. The mean total vestibular fluid space was 120.9 mm3 and mean total cochlear fluid space 83.6 mm3. In the vestibule, the perilymphatic space occupied 74.8%, and the endolymphatic space, 25.2%, whereas 90.8% of the cochlear fluid space was occupied by perilymph.

The Role of 3-Canal Biomechanics in Angular Motion Transduction by the Human Vestibular Labyrinth

“…These investigations typically consisted of canal plane calculations, endolymph volume estimates, or discrete measures of canal cross-sectional areas or sensory epithelia dimensions. 11,12,23,25 Although valuable, none of the previous studies provided a sufficient quantitative description of semicircular canal membranous labyrinth geometry to formulate an accurate 3D biomechanical model. Therefore, as part of the present work, we developed a method to extract cross-sectional area/shape and planar information from the membranous and bony labyrinths through detailed segmenting of histological sections and parameterization of the membranous labyrinth geometry.…”

Inner Ear Fluid Volumes and the Resolving Power of Magnetic Resonance Imaging: Can it Differentiate Endolymphatic Structures?

“…Using measurements from the plastic mold, histologic cross sections, and macrosections, as well as average figures given in various anatomy books and published articles, [1][2][3][4][5][6][7][8][9] we calculated the volume of the components of the bony labyrinth. The bony labyrinth is divided into 3 semicircular canals, 3 ampullae, a vestibule, and a cochlea (Fig 1).…”

“…[1][2][3][4][5][6][7][8][9] We divided the endolymphatic spaces into 3 semicircular canals and ampullae, I utricle, I saccule, and a cochlear duct. The results of these calculations are included in the The mathematical method using geometric formulae and measurements from anatomy books and histologic sections can provide only approximate figures.…”

“…We became interested in knowing the actual volumes of the perilymphatic and endolymphatic spaces of the inner ear structures, and whether it is possible to recognize such structures as the saccule, utricle, and membranous semicircular canals on MRI. In a search of the literature, including anatomy textbooks, [1][2][3][4][5][6][7][8][9] we found only I report I with more than isolated, incomplete data on the volumes of these structures.…”

Precise Neurotransmitter-Mediated Communication with Neurons In Vitro and In Vivo Using Organic Electronics

“…These sound waves are transduced into neural signals predominantly by the inner hair cells, a type of neuron specific to the cochlea that is activated by mechanical agitation of stereocilia ("hairs") on its surface. The total volume of the guinea pig cochlear perilymph is less than 10 µl 16) and in the human, approximately ten times that 17) . Hence, substance delivery involving fluid flow -for example, using osmotic pumps -tends to increase the pressure inside the cochlea and would affect the extremely mechanosensitive hair cells.…”