Diseases Of The Nose Throat And Ear

ANATOMY OF THE EAR

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peritubal cells and cells in the floor of the tympanum which may extend
towards the apex of the petrous bone.

The posterior and inferior aspects of the temporal bone are shown in Figs.
'136 and 137.

Fig. 136. Posterior aspect of left temporal bone. 1, Fossa subarcuata; 2, Internal acoustic meatus; 3,
Groove for superior petrosal sinus; 4, Groove for inferior petrosal sinus; 5t Canaliculus cochleae
(cranial opening of peri lymphatic aqueduct); 6, Processus styloideus; 7, Fossa jugularis (jugular bulb);
8, Tip of mastoid process; 9, Cranial opening of aqueduct of vestibule; 10, Groove for transverse
sinus; 11, Mastoid foramen (for mastoid emissary vein).

Fig. 137. Inferior aspect of left temporal bone.
1, Fossa mandibularis; 2, Fissura petro-
tympanica (Glaserian fissure); 3, Processus
styloideus; 4, Meatus acusticus externus; 5,
Processus mastoideus; 6, Incisura mastoidea
(digastric groove); 7, Sulcus arteriae occipitalis
(groove for occipital artery); 8, Foramen
stylomastoideum; 9, Fossa jugularis; 10,
Canaliculus tympanicus (opening for Jacobson's
nerve); 11, Apertura externa canaliculi cochleae
(cranial opening of perilymph aqueduct); 12,
Area for attachment of pharyngeal basilar
fascia; 13, Foramen carotidum; 14, Canal
for tensor tympani; 15, Pharyngotympanic
(Eustachian) tube.

THE INTERNAL EAR

The internal ear within the petrous part of the temporal bone consists of a
membranous labyrinth (Fig. 138) enclosed in a bony (osseous) labyrinth
(Figs. 139, 140). The membranous labyrinth contains fluid known as endo-
lymph and the space within the bony labyrinth between its walls and the
membranous labyrinth contains fluid known as perilymph.
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