HYPOTHYROIDISM 423 



sex characteristics but the genitalia are usually more hypoplastic when the 

 gonads are affected. The height and length of limb and the fat distribu- 

 tion should readily distinguish it. According to Engelbach and Tierney, 

 the adipose tissue is chiefly confined to the upper femoral region, "the tro- 

 chanteric fat pads." True infantilism (Falta) should cause no confusion 

 with hypothyroidism. Although growth retardation may be marked, yet 

 the symmetrical osseous and limb development and mentality for the 

 age at which normal growth ceased clearly distinguish this condition. 

 True Nanism is distinguished by a symmetrical development to the con- 

 dition of adult life, only differing from normal individuals in the abnor- 

 mally small size. 



Mongolism should cause no doubt in differential diagnosis. A certain 

 superficial resemblance to cretinism is present and has led older writers 

 to the recognition of various differential characteristics. Several hypo- 

 thyroid manifestations are presented among them retardation of growth, 

 dentition, and of mental development, delayed closure of the fontanelles, 

 protruding tongue, constipation, protuberant abdomen and umbilical 

 hernias. There seems indeed a thyroid factor in certain cases of mon- 

 golism as some improvement on thyroid treatment has been reported. The 

 finding of normal thyroids at autopsy (Comby and Bourneville (&)) 

 has disposed, however, of the possibility of an actual identity of 

 the two conditions. As differential features may be enumerated 

 the following: The Mongol head is bullet-like and covered with 

 silken hair, the cretin's larger and brachycephalic with sparse dry 

 hair, the Oriental expression of the former contrasting with the bestial 

 type of the latter. Small noses are characteristic of both diseases. The 

 Mongol nose is button-like on a broad base (Kassowitz). The cretin nose 

 is saddled and upturned, showing flaring nostrils. The Mongol tongue is 

 small and pyramidal, the hypothyroid child's over-large, broad and tooth- 

 marked. The Mongol's neck is normal, the cretin's short, fat, double- 

 chinned, with absent thyroid swelling or goiter. The distinguishing hair 

 and skin lesions of the cretin are lacking in the other disease. The hands 

 of both are very distinctive. The Mongol's are gracile and small, the little 

 fingers incurving, the end phalanx being displaced upon the next proximal. 

 The cretin's hands are stubby and plump with short thickened fingers blunt 

 at the tips. The genitalia of the Mongol, though small in males, suffer less 

 developmental delay than in the case of the cretin. Rontgenograms of the 

 bones lack, in the case of the Mongol, the distinctive delay in ossification 

 of hypothyroidism. 



Rickets can only cause confusion in atypical cases. The X-ray will 

 show hypertrophic epiphyseal areas and thickened epiphyseal cartilages, 

 irregular lines of ossification as compared to the delayed ossification and 

 straight epiphyseal lines of the cretin. Cliondrodystropliy is character- 

 ized by small stature, short thick bowed extremities. The mind, however, 



