Chap, ix.] THE NECK. 161 



fascia, platysma, and anterior jugular veins. The 

 sterno-hyoid, sterno- thyroid, omo-hyoid, and portion of 

 the sterno-mastoid have usually to be divided. The 

 tumour is carefully separated. The capsule that 

 invests the vascular gland must not be torn through. 

 The thyroid vessels are ligatured in situ before the 

 removal of the mass. The superior thyroid meets 

 the gland at the apex of the lateral lobe and is there 

 secured. The inferior thyroid artery enters the lower 

 part of the lobe at its posterior aspect. In securing this 

 vessel, and in liberating the lower part of the tumour, 

 the recurrent laryngeal nerve is in great danger of 

 being damaged. The thyroidea ima artery exists in 

 10 per cent, of all cases. 



The gullet commences opposite the sixth cervical 

 vertebra, and pierces the diaphragm opposite the 

 tenth dorsal vertebra. It presents three carves : 

 one is antero-posterior, and corresponds to the curve 

 of the spinal column ; the other two are lateral. 

 The gullet commencing at the middle line deviates 

 slightly to the left as far as the root of the neck ; 

 from thence, to the fifth dorsal vertebra, it gradually 

 returns to the middle line, and finally it turns again 

 to the left, at the same time passing forwards, to 

 pierce the diaphragm. Its length is from 9 to 10 

 inches. Its transverse diameter has been carefully 

 estimated by Dr. Mouton, by filling the gullet with 

 plaster of Paris in situ, and then measuring the cast 

 thus obtained. Dr. Mouton found that there were 

 three narrow parts in the gullet, one at its com- 

 mencement, one about 2^ inches from that point, and 

 a third where the tube passed through the diaphragm. 

 The diameter at each of these points was a little over 

 half an inch (14 mm.); the diameter elsewhere was 

 about % inch (17 mm. to 21 mm.). By forcible 

 distension the two upper narrow parts could be dis- 

 tended to a diameter of 18 to 19 mm., the lower part 



L-4 



