Bronchocele 135 



Relations. The gland is covered by the deep fascia, the sterno- 

 hyoid, sterno-thyroid, and omo-hyoid, and laterally by the sterno- 

 mastoid. Beneath it is the sheath of the common carotid, and on the 

 inner aspect are the trachea and larynx, the oesophagus (on the left 

 side), and the pharynx. 



The firm connection of the gland with the upper part of the wind- 

 pipe is a fact of great clinical importance ; when there is dilatation 

 of the vessels of one lobe a rounded tumour occurs in the groove 

 between the larynx and sterno-mastoid, which, pulsating with thrill and 

 expansion, strongly suggests aneurysm of the upper part of the common 

 carotid. On making the patient swallow, however, the tumour glides 

 up and down with the larynx : a carotid aneurysm is not influenced 

 by the movements of deglutition. An accessory thyroid gland is not 

 unknown. 



Supply. Arteries come from the superior, the inferior, and, some- 

 times, from the lowest thyroid branches. Of the veins, the superior 

 and middle enter the internal jugular, whilst the inferior descend in 

 front of the trachea as important tributaries of the innominates (p. 132). 

 The lymphatics enter the deep cervical glands. 



Nerves. Sympathetic filaments come from the cervical ganglia 

 along with the arteries, and other branches are derived from the external 

 and the recurrent laryngeals. 



Structure. There is a fibrous coat which sends in processes 

 dividing the gland into irregular lobules ; these consist of a gluey 

 material containing seed-like vesicles. The vesicles contain corpus- 

 cular elements and more of the glue, and, when greatly distended, 

 they cause cystic enlargement of the gland. Sometimes the cysts 

 contain serum, sometimes blood. 



The probable function of the gland is * the control of the muci- 

 noid substances in the tissues of the body, and the manufacture of 

 blood-corpuscles.' (Horsley.) When the gland is atrophied, also when 

 its bulk is increased at the expense of its proper elements, mucin is 

 deposited in the connective tissues, as of the eye-lids, lips, and hands, 

 so that they become puffy and permanently swollen. This disease is 

 called myxoedema^ and it is associated with the presence of an excess 

 of colourless, and a diminution in the number of red, corpuscles of 

 the blood. Horsley has produced the same association of symptoms in 

 monkeys by removing the thyroid body. And in children who are 

 born without a thyroid body the symptoms occur, begetting the disease 

 known as sporadic cretinism, in which the subject is idiotic. 



Enlargement of the thyroid gland, or bronchocele (jSpoy^os, wind- 

 pipe ; KrjX??, tumour], is called goitre in Switzerland, and, in England, 

 Derbyshire neck. The enlargement may be solid or cystic, lateral 

 or symmetrical. When the enlargement is due to dilatation of the 

 blood-vessels of the gland it is often associated with prominence of 

 the eye-balls and palpitation of the heart Graves' disease the pro- 



