16 ANTHROPOLOGY. 
behind with the occipital, and by the pterygoid processes with the palatine 
bones. | | 
Temporal bones, ossa temporum (pl. 121, fig. 1******; pl. 122, 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 (pl. 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 fossee by the con- 
volutions of the brain. The greater portion of the circumference of the 
squamous portion is bevelled for articulation with 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 (pl. 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 ( fig. 8°), which extends forwards 
to join the malar bone. 
The mastoid portion (pl. 121, fig. 1”, fig. 8") is thick and cellular, the 
upper portion being received between the parietal and occipital bones. The 
cells 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 temporal bone ( pl. 121, fig. 1 *; pl. 128, 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 internus (fig. 8°), for the transmission of the seventh or 
auditory and the facial nerve. Between the mastoid and zygomatic pro- 
cesses is the meatus auditorius externus (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 (pl. 121, fig. 10, from above; jig. 11, from 
below; fig. 12, from behind; fig. 18, from before; fig. 14, from the orbitar 
side; 15, from the nasal or inner side; fig. 16, the septum). This bone 1s 
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 eribrosa (fig. 10*), with a 
vertical median ridge or process called the crista galli (figs. 10, 12, 18, 16°). 
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