THE SKULL AND THE BONES OF THE SKULL 



103 



Squamous portion of the temporal bone 



Squama temporalis 



The incus - 



Incus 



Cartilaginous portion of the primordial cranium 

 Pars cartilaginea cranii primordialis 



Cartilaginous bar of the hyoid or second ' 

 visceral arch (primitive cartilage of 

 the styloid process) 



Cartilaginous bar of the mandibular or first 

 visceral arch (Meckel's cartilage) 



Mandible 

 Mandibula 



, The malleus 



\ Malleus 



\ 



t 



1 Tympanic ring 

 Annulus tympanicus 



FIG. 225. THE SQUAMOUS PORTION OF THE TEMPORAL BONE, THE TYMPANIC MEMBRANE WITH THE 

 MALLEUS, THE INCUS, AND MECKEL'S CARTILAGE, FROM A HUMAN FCETUS IN THE FIRST HALF 

 OF THE FIFTH MONTH (MONTHS OF FOUR WEEKS EACH). SEEN FROM WITHIN. 



Body-length, 5^ inches. 



Squamous portion of the temporal bone 



Squama temporalis 



Membranous portion of the primordial cranium 

 Pars membranacea cranii primordialis \ 



Greater wing 



Ala magna 



Squamous portion of the frontal bone 

 Squama frontalis 



Cartilaginous bar of the mandibular or first 



visceral arch (Meckel's cartilage) 

 Cartilaginous bar of the hyoid or second 

 visceral arch (styloid process, stylohyoid 

 ligament, and small cornu of the hyoid 

 bone) 



Maxilla 

 Maxilla 



Parietal bone 



/ Os parietale 



Tympanic ring 



/'Annulus tympanicus 



Intermembranous part of the supra-occipital 



portion ol uhe occipital bone 1 

 Pars intermembranacea squamae occipitalis 



Cartilaginous portion of the primordial cranium 

 Pars cartilaginea cranii primordialis 



' Intracartilaginous part of the supra-occipital 

 portion of the occipital bone 1 



Pars intracartilaginea squamae occipitalis 



.._ Foramen magnum 

 ~ Foramen occipitale magnum 



'"-Lateral portion of theoccipitalbone(exoccipital) 1 



Pars lateralis ossis occipitalis 



Basilar portion of the occipital bone (basi-occipital) 1 

 Pars basilaris ossis occipitalis 



Mandible 

 Mandibula 



Primitive cartilage of the hyoid bone 



Knorpelanlage des Os hyokieum '.Primitive cartilage of the petrous portion 



Cartilaginous portion of the primordial cranium of the temporal bone 



Pars cartilaginea cranii primordialis Knorpelanlage der Pars petroea 



1 See note to p. 57. 



FIG. 226. THE SKULL OF A HUMAN FCETUS IN THE MIDDLE OF THE FIFTH MONTH (MONTHS OF 

 FOUR WEEKS EACH). SEEN FROM THE LEFT SIDE AND BELOW. 



Body length, 6i inches. The cartilaginous bars of the visceral arches are displayed, and these, together 

 with the cartilaginous portion of the primordial cranium, are coloured blue. Part of the cartilage of 

 the left side of the inferior maxilhi has been removed in ouk-r to lay bare a i ortion of Meckel's 

 cartilage which lies beneath it. 



FIG. 227. THE DRIED SKULL OF A HUMAN 

 FCETUS IN THE MIDDLE OF THE FOURTH 

 MONTH (MONTHS OF FOUR WEEKS 

 EACH). 



Body-length, 3$ inches. 



FIG. 228. THE DRIED SKULL OF A HUMAN 

 FCETUS AT THE END OF THE SIXTH 

 MONTH (MONTHS OF FOUR WEEKS 



EACH). 



Body-length, u^ inches. 



Development ot the Skull. 



