64 



THE SKULL AND THE BONES OF THE SKULL 



Petrosquamous fissure 

 Fissura petrosquamosa 



Mastoid portion 



Pars mastoidea \ 



Tegmen tympani ; 



Tegmen tympani\ 



Petrous portion 



Pars petrosa (Pyramis)"~-~.. 



Hiatus Fallopii 



Hiatus canalis facialis 



Groove of great superficial petrosal nerve 



Sulcus h. petrosi superficialis raajoris 



Groove of small superficial petrosal nerve. 

 Sulcus n. petrosi superficialis minoris 



Apex of the petrous portion 

 Apex pyramidis 



Carotid canal / 

 Canalis caroticus 



-Cerebral surface 



Squamous portion of the temporal bone 



Squama temporalis 



Sphenoidal border 

 Margo sphenoidalis 



Zygoma 



Processus zygomaticus 



Canal for the tensor tympani muscle 



Semicanalis musculi tensoris tympani 

 Bony septum (cochleariform process) 



""Septum canalis musculotubarii 



Eustachian canal 

 Semicanalis tubs auditivae 



Tympanic plate 



Pars tympanica 



Mastoid process 



Processus mastoideus 



^Styloid process 



Processus styloideus 



FIG. 131. THE LEFT TEMPORAL BONE SEEN FROM BEFORE. 



Epitympanic recess, or aditus ad antrum 

 Recessus epitympanicus 



*Fossa of the incus 1 

 *Fossa incudis 



Petrosquamous sulcus (var.) 

 Sulcus petrosquamosus (var.) 



Mastoid antrum 



Antrum tympanicum--. 



Sigmoid sulcus 



Sulcus sigmoideus 



Mastoid cells 

 Cellulae 



Aqueduct of Fallopius Canalis facialis (Fallopii)/ 

 Inferior orifice of the canal for the chorda tympani nerve/ 



(iter chordae posterius) 

 Canaliculus chordae tympani (Apertura inferior) 



Cupular portion of the epitympanic recess 

 Pars cupularis recessus epitympanici 



Tegmen tympani 



Tegmen tympani 



Petrosquamous fissure 



Fissura petrosquamosa 



Notch of Rivinus 

 ---" Incisura tympanica (Rivini) 



Vi 



Anterior tympanic spine 



Spina tympanica major 



Posterior tympanic spine 

 Spina tympanica minor 

 Tympanic sinus 

 Sinus posterior 



Tympanic sulcus Sulcus tympanicus 

 ^Tympanic orifice of canal for chorda tympani nerve 



Canaliculus chords tympani (Apertura tympanica) 



Vaginal process Vagina processus styloidei 

 Styloid prominence Prominentia styloidea 

 / Stylomastoid foramen Foramen stylomastoideum 

 Canaliculus for auricular branch of pneumogastric (Arnold's nerve) 

 Canaliculus mastoideus 



1 *Fossa of the incus. ( The shorter process (crus t>revi) of the incus projects backwards. Its extremity is tipped with cartilage ai d is 

 . . . articulated by ligamentous fibres [ligament of the incus] with the posterior and partly with the outer wall of the tympanum near the 

 entrance to the mastoid cells. The place where the ligamentous fibre* are attached to the wall of the tympanum is somewhat depressed, and 

 has a covering of cartilage.' Quains 'Anatomy,' tenth edition, vol. iii., part iii., p. go. fossa of the incus is a most suitable name for this 

 depressed cartilage-covered area, and may well be adopted by English anatomists. TR. 



FIG. 132. THE EXTERNAL WALL OF THE TYMPANUM AND THE MASTOID CELLS DISPLAYED BY 

 A SECTION, THROUGH THE LEFT TEMPORAL BONE IN A PLANE PARALLEL WITH THE 

 SQUAMOUS PORTION OF THAT BONE. 



The petrosquamous sulcus (along which a sound has been passed) is in this specimen partly bridged 

 over by bone ; anteriorly it communicates with the outer surface of the bone by means of a spurious 

 jugular foramen foramen jugulare spurium (Variety). 



Os temporale The temporal bone. 



