14 



Bones of the Skull. 



Squama temporalis 



I 



Incisura 

 parietalis 



Sutura 

 squamoso- 

 mastoidea 



Processus 

 zygomaticus 



-Tuberculum articulare 

 - Fossa mandibularis 



Fissura petrotympanica 

 [Glaserij 



Foramen / v Pars petrosa 



stylomastoideum ; / Annulus tympanicus 



Fenestra vestibuli Promontorium 



13 and 14. Right temporal bone, os temporale, 



from the newborn child, seen from without. 

 (13: complete, 14: squama temporalis and annulus tympanicus alone.) 



Squama temporalis 



Sulcus arteriostiSs 



Fissura petrosquamosa 



Tcgmen tympani 

 Incisura parietalis 

 Kminentia arcuata 



Geniculum canalis 



facialis et sulci 

 nn. petros. superf. 



Canalis caroticus 



Impressio trigemini / ; / / < Apertura externa aquaeductus vestibuli 

 Facies posterior pyramidis / / , Incisura jugularis 



Porus acusticus internus / Apertura externa canaliculi cochleae 

 Fossa subarcuata 



15. Right temporal bone, os lemporaie, 



from newborn child, seen from within. 



The OS temporale consists in the foetus of three parts, pars petrosa, squama tempo- 

 ralis and pars tympanica (see also p. 8); in the newborn it is still divided into all three or 

 into only two parts according as the squama temporalis and pars tympanica still remain 

 separated or have united with one another. The pars tympanica in the newhorn is a flat 

 semicircle, the annulus tympanicus ; it is open above and contains in its concavity the sulcus 

 tympanicus (see p. 13); out of it the pars tympanica ultimately develops in that it grows out 

 chiefly in a lateral, less in a medial direction to form a groove. 



In the newborn no actual proc. mastoideus exists. The foramen stylomastoideum lies 

 on the lateral surface of what is later to be the pars mastoidea. The proc. styloideus is still 

 cartilaginous. On the posterior and anterior surface of the pyramid the size of the fossa 

 subarcuata (p. 9) and the site of the geniculum canalis facialis (pp. 11 12) not yet bridged 

 over by bone, are striking features ; accordingly, a hiatus canalis facialis, in the sense in which 

 it exists in the adult, is absent in the newborn. 



