124 



Development 



arches through which the cervical epiblast blends with the pharyn- 

 geal hypoblast. From the first cleft the Eustachian tube and tym- 

 panum are developed, the meatus auditorius grows from its hinder end, 

 and the pinna from the neighbouring integument (p. 102). 



Branchial fistulae may be found in the middle line of the neck, 

 where the lateral arches have failed to meet, and down the side of the 

 neck, by the anterior border of the sterno-mastoid, where the blending 

 of the adjacent arches has been imperfect. Their most common 

 situations are shown in the adjacent sketch, which has been kindly lent 



by Mr. Bland Sutton, to 

 whose Lectures in the 

 ' Lancet' of 1888 the 

 reader will do well to 

 refer. These fistulas 

 lead by slender canals 

 deeply into the neck, 

 towards the pharynx, 

 with which they were 

 originally continuous. 

 Sometimes they are in 

 symmetrical pairs. 

 Paget has noticed that 

 their secretion is aug- 

 mented during bron- 

 chial or nasal catarrh. 



Occasionally a small 

 pendulous nodule of 

 skin, or of skin and 

 cartilage, marks part of 

 the line of closure of 

 one of the clefts, just as 

 nodules grow at the end 

 of the first post-oral 



A F, A F', situations of congenital auricular fistula: ; i, H, in, fissure to form the pill- 



IV, external orifices of branchial fistulae, I being the ex- na, and Sometimes a 



ternal auditory meatus ; OF, orbital fissure; M F, man- . .. 



dibular fissure ; H H, lines of hare-lip ; c F, c F', show Similar nodule persists 



median cervical fistulae. j n the m jddle line as a 



clumsy representative of a needless raph^, by way of evidence of the 

 fusion of the plates in the middle line. 



Derm old cysts, which are frequently found in the face, neck, and 

 pinna, are due to pieces of the epiblast in some of the clefts having 

 been closed in externally ; their epidermal lining secreting a seba- 

 ceous material, the cysts become conspicuous, and may in due course 

 demand removal. Sometimes the cysts contain hair and sebaceous 

 glands. 



