ON EPIGNATHUS jc 



The stalk of attachment consists of a core of fibrous tissue on which 

 are prolonged delicate laminae of bone from the hard palate, and also 

 from the vomer which is represented by two thin separate bony laminae 

 on each side of the nasal septum. In the fibrous tissue is embedded a 

 piece of bowel. On its outer aspect the stalk is covered by mucous 

 membrane. Between the mucous membrane and the laminae of bone the 

 main blood vessels for the tumour pass down. On the left side two 

 blood vessels of fair size pass down from the posterior palatine foramen 

 to the tumour, where they form a profuse vascular network. Along with 

 these blood vessels, some bundles of the great palatine nerve can be 

 traced on to the stalk for a short distance. 



Another large artery— as large as the radial artery in the adult- 

 issues from the left spheno-palatine foramen, crosses over the roof of the 

 left nasal fossa, gains the posterior border of the nasal septum, and 

 descends in the thickened tissue behind this into the right half of the 

 tumour. 



Under the mucous membrane of the posterior part of the stalk a 

 large thin-walled vein runs up under the fibrous periosteum of the basi- 

 sphenoid, and passing through a canal in the cartilage, between the 

 basi-sphenoid and basi-occipital, communicates with the left cavernous 

 sinus. 



Summary of the attachment and structure of the Tumour. 



The tumour is attached to the posterior half of the hard palate and 

 partly to the basi-sphenoid. It is of interest to note that the nasal 

 septum is complete. The relations of the attachment are such as to 

 suggest that the tumour in its origin might have had an early connection 

 with the mesial nasal process, and had been carried back along with the 

 mesial nasal process through between the developing palatal processes. 



The blood supply of the tumour is mainly derived from a much 

 enlarged left spheno-palatine artery, and also from a branch of the left 

 posterior palatine artery. The blood is returned by two veins, one large 

 vein opening into the left cavernous sinus, and another smaller vein, 

 a tributary of the left posterior palantine vein. 



Structurally, the tumour is one of the higher forms of epignathus, 

 containing recognisable foetal organs. A peculiarity of the specimen is, 



(189) 



