ACROMEGALY 833 



megalic. The external angular process of the frontal bone and ascending 

 process of the malar the whole outer wall of the orbit is actually pro- 

 longed or moved forward. Not only so, but the zygoma in relation to the 

 cranial cavity is lowered, thus increasing the height of the temporal fossa 

 by depressing its floor. The external auditory meatus in some cases is 

 depressed 10 mm. or more." The temporal development causes a for- 

 ward growth of the orbital region. The external angular process of the 

 frontal bone and the ascending process of the malar occupy a position 

 from 10 to 15 mm. further forward and downward than in the normal 

 skull. The nose becomes long and remarkably prominent but the nasal 

 bones are very little enlarged. The great development of the supraorbital 

 region of the forehead has forced the root of the nose downward and for- 

 ward. In the orbit the chief change concerns its outer wall, the enlarge- 

 ment of which is connected with that of the temporal bone. The growth of 

 the malar bones and zygoma is striking and apparently stimulated by the 

 traction of the masseter. 



Vault Changes. The changes in the vault of the skull are most 

 marked in the frontal region. Thus, between the origin of the temporal 

 muscles a strong sagittal arch of bone is built up so as to provide a strong 

 fulcrum for these muscles and the same condition is present in the gorilla. 



Occiput. In the occipital region a wide crest may form in the region 

 of the superior curved lines corresponding to a similar formation in the 

 anthropoid apes. The area of insertion of the muscles of the neck is 

 greatly enlarged, the inion is moved upward and the mastoid processes are 

 wider apart by 10 to 25 mm. 



Bella Turcica. The sella turcica is of particular importance as ront- 

 genologic demonstration of its enlargement constitutes one of the earliest 

 indications of hypophyseal tumor. The honor of having pointed this out 

 as early as 1899 belongs to Oppenheim(a). It has been most minutely in- 

 vestigated in the living and in dead subjects, and numerous authors supply 

 us with illustrations of innumerable normal and abnormal variations in its 

 size and shape, as well as with detailed measurements. Keith gives the 

 following dimensions in normal male skulls : antero-posterior diameter 10 

 to 12 mm., transverse diameter 14 to 15 mm., depth 8 mm. Gushing 

 states that profile radiographic measurements exceeding 15 mm. antero- 

 posteriorly and 10 mm. in depth may be looked upon as indicating an en- 

 largement. Howe gives the measurements by different authors, pictures 

 tracings of the sellar outlines of forty normal individuals and rightly con- 

 cludes that "the pituitary fossa is normally subject to great variations in 

 size and outline and gives no information concerning the condition of the 

 pituitary gland unless there is very marked sellar enlargement or absorp- 

 tion of some portion of the bony envelope." Schiiller(a) has shown that 

 the two commonest variations. the short and deep and long and rather flat 

 types of sella seem to depend on the general shape of the skull, whether 



