16 ANJ'HROPOLOGY. 



beilind witli the occipital, and by tlie pterygoid processes with the palatine 

 bones. 



Temporal bones, oasa temporum {j^l 121, fig. !"• "' ''• '*; pi. 121.^ figs. 8, 9). 

 These bones form portions of the inferior lateral walls and of the base of 

 the cranium. They articulate with the occipital, the parietal, the sphenoid, 

 inferior maxillary, and the malar. Their figure is very irregular, consisting 

 of three portions, the squamous, the petrous, and the mastoid. 



The squamous portion [pi 121, fig. 1*) is the thin circular and anterior 

 part which forms the inferior portion of the temples. The exterior surface 

 is smooth and slightly convex, the interior is formed into fossae by the con- 

 volutions of the brain. The greater portion of the circumference of the 

 squamous portion is bevelled for articulation Avith the parietal and sphenoid 

 bones ; at the anterior inferior part, however, it is serrated and thicker. 

 On the exterior of this portion is the glenoid cavity (^^. 122, fig. 8') for 

 articulating with the lower jaw. The outer margin of this cavity is consti- 

 tuted by the base of the zygomatic process {fi^. 8'), which extends forwards 

 to join the malar bone. 



The mastoid portion {pi. 121, fig. V\ fig. 8') is thick and cellular, the 

 upper portion being received between the parietal and occipital bones. The 

 (jells known as the mastoid sinuses communicate with the tympanic cavity. 

 We also distinguish a mastoid process for the attachment of the sterno- 

 mastoid and trachelo-mastoid muscles ; together with a mastoid foramen, 

 for the passage of a vein into the lateral sinus. 



The petrous portion of the temp>oral hone {pjl. 121, fig. 1"- " ; 7:)?. 123, fig. 9 '' °) 

 is a triangular pyramid, arising from the inner side of the mastoid and 

 squamous portions. In the posterior surface of the petrous bone is the 

 meatus auditorius intermis [fig. 3 * ), for the transmission of the seventh or 

 auditory and the facial nerve. Between the mastoid and zygomatic pro- 

 cesses is the meatus avditorius exteryius {fig, 8 ^ ), which leads to the tympa- 

 num. Its rough lower margin is called the auditory process, and to it is 

 attached the cartilage of the external ear. The styloid process for the 

 attachment of the styloid muscles is seen in fig. 9 ^ Behind the root of this 

 process is the stylo-mastoid foramen, which transmits the facial nerve to the 

 face. The jugular fossa, which is situated within the styloid process and 

 the foramen, is occupied, in conjunction with a similar one in the occipital 

 bone, by the internal jugular vein, and the eighth pair of nerves. Anterior 

 to the lower end of this fossa is the foramen caroticum, through which 

 passes the carotid artery and the upper extremity of the sympathetic nerve. 

 The orifice of the eustachian tube is to be found in the angle between the 

 squamous and petrous parts, within the glenoid foramen. 



The ethmoid bone, os ethmoides {pi. 121, fig. 10, from above ; fig. 11, from 

 below; fig. 12, from behind; fig. 13, from before; fig. 14, from the orbitar 

 side ; 15, from the nasal or inner side ; fig. 16, the septum). This bone is 

 so placed as to fill the vacancy between the orbitar processes of the frontal 

 bone. It is cuboidal, and highly cellular. The only part which looks 

 towards the brain is the cribriform plate, lamina cribrosa {fig. lO''), with a 

 vertical median ridge or process called the crista galli {figs. 10, 12, 13, 16'). 

 722 



