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A TEXTBOOK OF PHYSIOLOGY 



There are in general two types of cretins, the myxoedematons 

 and the nervous. The nervous type, met with chiefly in India, are 

 generally deaf and dumb. The upper limbs often assume a position 

 of right-angled flexion, with the thumb drawn into the palm and the 

 fingers closed over it. The lower lunbs exhibit a " knock-kneed " 

 spasticity. These cretins suffer from convulsive movements of the 

 head, nystagmus, internal squint, and idiocy. 



The myxoedematous type shows marked interference with the 

 growth of the skeleton, leading to a stunted, pot-bellied appearance. 

 There is usually a marked lack of mental efficiency, a child of twelve 



FIG. 253. XuN-(jloiTKOus CRETINS. (Photographs kindly lent by Ih-. Robert 



Hutchison.) 



to sixteen having the intelligence of a child of two or three. The 

 appearance remains childish throughout life. Often fatty tumour- 

 make their appearance in the region of the collar-bone. 



When thyroid deficiency first manifests itself in the adult, the 

 effects upon growth are naturally absent. A gradual SAvelling of the 

 skin sets in, frequently accompanied by nervous disorders, such as 

 headache, languor, convulsions, mental disturbances, dulness, drowsi- 

 ness, or even hallucinations. Tlio skin becomes wrinkled, dry and 

 rough, swollen generally, but with a " solid oedema," hence the name 

 " myxoodema " (mucous oedema). The swelling is at first most notice- 

 able on the face (see Fig. 254). The hair becomes scanty, the scalp 

 dry and scaly. The teeth often become carious. 



