8 



Bones of the Skill 1. 



Squama 

 temporalis 



Fades cerebralis 

 Sulcus arteriosus 



Margo 

 parietalis 



Margo mt 

 sphenoidalis 



Impressio trigemini - 



Angulus superior pyramidis 



Sulcus petrosus inferior 

 Facies anterior pyraniidis 

 Angulus posterior pyraniidis 7 

 Porus acusticus intcrnus 



Apertura externa canaliculi cochleae 



\ 



Fissura petrosquamosa 



Eminentia arcuata 



Incisura parietalis 

 Sulcus sigmoideus 



Foramen mastoideum 



.Margo 

 occipitalis 



Sulcus petrosus superior 



Facies posterior pyraniidis 



Fossa subarcuata / / 

 Processus intrajugularis Apertura externa aquaeductus vrstibuli 



Tncisura jugularis 



A A 



Pars petrosa 



Pars mastoidca 



8. Right temporal bone, os lemporale, from within and above. 



The pars mastoidea (see also Figs. 1, 915, 55, 56, 59, 60 and 6366) is a thick 

 conical projection not well developed until adult life. Developmental!}" it is not an independent 

 part of the bone, but a secondary outgrowth from the lateral and most posterior part of the 

 temporal bone ; its anterior superior portion develops from the squama temporally its posterior, 

 inferior portion from the pars petrosa (see Figs. 1214). Its posterior, serrated margin, mar go 

 occipitalis, comes into apposition with the margo mastoideus oss. occipitalis (sutura occipito- 

 mastoidea) ; the short upper serrated margin terms with the rnargo parietalis of the squama 

 temporalis an angular indentation, the incisura parietalis , in which is received the angulus 

 mastoideus oss. parietalis (sutura parietomastoidea) above and in front it goes over into the 

 squama temporalis, in front it adjoins the pars tympanica; the site of junction of the two 

 components is indicated lateralward in the adult in about one -third of the cases by the sutura 

 squamosomastoidea which runs obliquely downward and forward. The lateral surface is convex 

 and slightly roughened (for the attachment of the mm. auricularis posterior et occipitalis), and 

 often presents behind one or several foramina mastoidea (for the ramus mastoideus a. occipitalis, 

 emissarium mastoideum) which open on the medial surface in the sulcus sigmoideus. Projecting 

 lateralward from the posterior superior margin of the porus acusticus externus there is frequently 

 found a small spur, the spina supra mealum; the surface behind it, often depressed, the fossa 

 mastoidea, extends above as far as the linea temporalis and is perforated by numerous foramina 

 for blood vessels. 



