126 



SPECIAL ANATOMY OF THE SKELETON 



.sphenoidal, and petrosphenoidal. In the middle line, from before backward, 

 is the optic groove, which supports the optic commissure; the groove terminates 

 on each side in the optic foramen, for the passage of the optic nerve and ophthal- 

 mic artery; behind the optic groove is the olivary process and laterally the anterior 

 clinoid processes, to which are attached processes of the tentorium cerebelli. 

 Farther back is the sella turcica, a deep depression which lodges the hypophysis, 

 bounded in front by a small eminence on either side, the middle clinoid process, 

 and behind by a broad, square plate of bone, the dorsum sellae, surmounted at 

 each superior angle by a tubercle, the posterior elinoid process; beneath the latter 

 process is a notch, for the abducent nerve. On each side of the sella turcica is 

 the carotid groove; it is broad, shallow, and curved somewhat like the italic letter/; 

 it commences behind at the foramen lacerum medium, and terminates on the inner 



FIG. 96. Median sagittal section of the skull. 



side of the anterior clinoid process, and presents along its outer margin a ridge of 

 bone. This groove lodges the cavernous sinus, the internal carotid artery, and 

 the nerves which enter the orbit. The sides of the middle fossa are of considerable 

 depth; they present depressions for the convolutions of the cerebrum and grooves 

 for the branches of the middle meningeal artery; the latter commence on the outer 

 side of the foramen spinosum, and consist of two large branches, an anterior and 

 a posterior; the former passing upward and forward to the anterior inferior angle of 

 the parietal bone, the latter passing upward and backward. The following foramina 

 may also be seen on either side from before backward. Most anteriorly is seen 

 the sphenoidal fissure (foramen lacerum anterius), formed above by the lesser wing 

 of the sphenoid; below, by the greater wing; internally, by the body of the sphenoid; 

 and sometimes completed externally by the orbital plate of the frontal bone. It 



