PATHOLOGICAL ANATOMY AND HISTOLOGY 769 



foal. Each hypophysis had its own sella turcica. Ahlfeld saw a double 

 hypophysis in a human infant. 



Congenital displacements of the hypophysis are more common than its 

 absence or its reduplication. Spring, Klinkosch, and Exner each observed 

 the hypophysis in the sac of an encephalocele which projected either 

 through a patent craniopharyngeal canal or through a cleft (Exner) in 

 the base of the skull. In a pig embryo Jakoby found the hypophysis in 

 contact with the roof of the pharynx. Suchanek and Haberfeld(6) have 

 each reported a case in which the hypophysis was found wedged into a 

 patent craniopharyngeal canal with its upper end at the floor of the sella 

 turcica, and its lower end projecting into the roof of the pharynx. The 

 shape of the gland was greatly distorted. Lawson found a "struma of the 

 hypophysis" growing through a defect in the sphenoid bone. In three cats 

 Haberfeld(a) found patent craniopharyngeal canals containing hypophy- 

 seal tissue, but with similar tissue also in the normal position in the sella. 

 Eossle has reported a case of dystrophia adiposogenitalis in which the 

 infundibulum was absent. 



Accessory hypophyses in the form of rests are common. Haberfeld(a), 

 Christeller, Pende(a), and Civalleri found these quite constantly in human 

 subjects. They are present in the mucous membrane of the vault of the 

 pharynx and along the front surface of the infundibulum. Their physio- 

 logical significance is disputed. They are important, however, because 

 they may give rise to tumors. 



Acquired malformations of the hypophysis are not uncommon. Total, 

 or almost total, absence of one or both lobes, due to some pathologic process, 

 has been recorded by Boyce and Beadles (&), Simmonds(/0, Bleibtreu, 

 Fraenkel(Z>), and Ponfick(a). Changes in the shape of the hypophysis 

 may result from various causes. When it is hypertrophied, as in preg- 

 nancy, it is more plump and Simmonds(e) has described it as shaped like 

 a "full sausage." In old age, the pit which is normally present on its 

 upper surface is deepened, and the gland becomes somewhat trough-shaped. 

 In cases of pressure upon the hypophysis by hydrocephalus and by tumors 

 of its infundibulum or in the floor of the third ventricle of the brain, it 

 becomes flattened and scaphoid. When the carotid arteries are tortuous, 

 dilated and partially calcified, the hypophysis may become faceted on its 

 lateral surfaces. Kiimmel and Eheinharclt found the hypophysis dis- 

 placed, compressed and flattened by pressure from aneurysm of one of 

 the vessels of the circle of Willis. 



Mechanical Injury 



Trauma. The hypophysis may be injured in trauma of the skull. 

 Schmorl observed hemorrhagic necrosis of the hypophysis in a case of 

 fracture of the base of the skull. Simmonds(/) has "frequently seen hem- 



