CHAPTEK XIV. 

 DISEASES OF THE DUCTLESS GLANDS. 



THE THYROID GLAND. 



Enlargements of the thyroid gland are usually spoken of as 

 goitres. These may be of various kinds, such as parenchymatous, 

 cystic, adenomatous or malignant. The goitre of Graves's 

 disease is sometimes termed vascular, but this does not 

 accurately describe the condition. From whatever cause the 

 gland is enlarged, its anatomical relations have important bear- 

 ings on the position and movements of the tumour and the 

 symptoms it may produce. The almond-shaped lateral lobes with 

 their isthmus give a characteristic horse-shoe shape to the gland 

 which is retained in all instances of uniform enlargement, The 

 right lobe is larger than the left, and this normal disproportion, 

 being maintained in general enlargement, may lead to an 

 erroneous impression that the right lobe is more increased in 

 size than the left. A middle lobe may sometimes be detected, 

 passing upwards on the front of the larynx this is the pyramidal 

 lobe which is usually attached to the hyoid bone by the fibrous 

 remnants of the thyro-glossal duct. The well-recognised clinical 

 facts that thyroid tumours follow the up and down movement of 

 the larynx during deglutition, and also accompany it when moved 

 laterally, are accounted for by the investment of the gland 

 in a capsule which is derived from the deep cervical fascia and 

 closely attached to the larynx. This fascial capsule is fixed in 

 front to the anterior arch of the cricoid cartilage and also to the 

 lower borders of the alae of the thyroid cartilage. That part of 

 the capsule which invests the inner and back parts of the lateral 

 lobes also sends fibrous prolongations to the sides of the cricoid 

 cartilage. These prolongations are known as the suspensory 



C.A.A. 19 



