Chap, ix.] THE A'ECK. 157 



chyroid may be considered to be enlarged. Its usual 

 weight is between one and two ounces. Each lobe 

 extends from about the middle of the thyroid cartilage 

 to the sixth ring of the trachea. It is larger in 

 females than in males, and the right lobe is usually 

 larger than the left. In connection with these matters 

 it may be noted that thyroid enlargements (broncho- 

 cele, goitre) are more common in females than in males, 

 and in any case are more apt to be first noticed on the 

 right side. The body being closely adhei'ent to 

 the trachea and larynx, it follows that it moves 

 up and down dxiring deglutition, and this circum- 

 stance is of the utmost value in the diagnosis of 

 bronchocele from other cervical tumours. The thyroid 

 when enlarged may distort and narrow the trachea, 

 and this is all the more likely to be the case when the 

 enlargement occurs rapidly, since the body is held 

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

 hyoid muscles. The, enlarged gland is apt to press 

 especially upon the veins of the neck, producing en- 

 gorgement of the face and head, upon the sterno- 

 mastoid muscle, and the other muscles named, upon 

 the cervical nerves, and particularly the recurrent 

 laryngeal. In some cases of dyspnoea produced 

 by rapidly growing bronchoceles, Bonnet has pro- 

 .posed subcutaneous section of the muscles. Since 

 the isthmus must bind together the enlarging lobes 

 of a bronchocele, Sir Duncan Gibb, on the other 

 hand, proposed to divide the isthmus in cases where 

 dyspnoea resulted. This operation he performed 

 several times with great relief to the patient. The 

 posterior border of the thyroid body being in con- 

 tact with the sheath of the great vessels, it follows 

 that the gland when enlarged may readily receive 

 pulsations from those vessels. It generally touches 

 also the lower part of the pharynx, and the upper 

 part of the gullet behind, and enlargement in this 



