PARATHYROID GLAKDS 623 



in the hands and feet (acroparesthesia) and the motor symptoms of tetany 

 may be regarded as analogues of the paresthesias and the vasomotor 

 phenomena known as Raynaud's disease. Raynaud's disease might, he 

 thinks, be designated a vasomotor tetany," just as acroparesthesia might 

 be termed "sensory tetany." Weber even hints that they may all have a 

 similar etiology. 



12. The Skin in Tetany 



In addition to the hyperhidrosis, the dermographismus, and the 

 erythemas observed in tetany (already described under disturbances of 

 the vegetative nervous system), one meets, in the literature of tetany, 

 reports of pigmentations and of outbreaks of urticaria and of herpes. 

 These complications are, however, relatively rare, and it is by no means 

 certain that they are not merely accidental associations, not definitely re- 

 lated to the main process. 



13. The Muscles, Bones and Joints in Tetany 



Joints. Joint swellings have often been mentioned in descriptions of 

 tetany. It will be remembered that one of the earliest observers of 

 tetany, Steinheim, regarded the disease as a peculiar form of rheumatism. 

 Some of the joint symptoms described were doubtless complicating 

 arthritides ; others seem to have been more of the character of intermittent 

 hydrops. 



Muscles. The tonic muscle spasms characteristic of manifest tetany 

 have already been described (vide supra) and mention has also been made 

 of the fibrillary twitchings and the clonic contractions that are occasionally 

 seen. Paresis of muscles has frequently been observed in tetany and is 

 an important, though a frequently overlooked part of the tetany syndrome. 

 True muscular atrophy, as well as true muscular dystrophy, has some- 

 times, though rarely, been observed in association with tetany. 



Bones. The bones have been but little studied in human tetany, 

 though Schiiller has described a form of osteoporosis observable in x-ray 

 plates. Attention has often been directed, too, to the frequent association, 

 in childhood, of tetany with rickets. 



The bone changes in experimental tetany have been carefully described 

 by Erdheim. After removal of the parathyroid glands in young rats, he 

 found that the newly forming bone tissue in the developing skeleton failed 

 to become calcified, or, if calcification occurred, it was delayed and in- 

 complete. The* lime-poor bone tissue resembled that observable in rickets 

 and in osteomalacia. 



Interesting studies of the skeleton in experimental chronic tetany, 



