470 PEOr. B. C. A. WINDLE OK TERATOLOGICAL EVIDENCE 



the femur and the acetabulum, Cruveilliier and Chelius to tlie 

 position of the fojtus in utero or to violence in delivery, Ammon 

 to arrest of development, Gruerin to irregular nervous action, 

 and South to an abnormal method of delivery. E-eceut writers, 

 he proceeds, have assumed that the last-mentioned cause is 

 always the correct one. This, however, is not the case ; the 

 specimen which he himself dissected was perfectly normally 

 delivered by a head presentation. Other observations point to 

 the fact that one of the causes, if not the chief cause, is a failure 

 of development of the acetabulum due to a lack of material. 

 Shaw, describing a living specimen, states that on digital exam- 

 ination, " a projecting irregularly shaped surface, supposed to be 

 the imperfectly-developed acetabulum, was felt " *. Shepherd t 

 has described a case which he had the opportunity of dissecting. 

 The female, aged about 50, had the right leg smaller and shorter 

 than the left. The wing of the right ilium was thinner, more 

 upright, more curled inwards, and smaller. The acetabulum 

 was a mere triangular depression in the bone with its apex di- 

 rected upwards and to the right and its base corresponding to 

 the cotyloid notch. The edges of this triangular depression were 

 smooth and curled inwards and but slightly covered with fibro- 

 cartilage. Its measurements vrere 2 in. long, | in. broad, | iu. 

 deep. Grrawitz X, in a paper on the subject, refers the malforma- 

 tion to a failure of development of the T-sbaped cartilage. In 

 twelve cases which he examined, there was no trace of any 

 inflammation of the joint as the cause. Whilst believing that a 

 defect of development is the chief cause, the possibility of 

 irregular or excessive nervous action being also a factor must not 

 be overlooked, since the improper action of the muscles arising 

 from it may induce the displacement of the head of the femur 

 from the imperfectly developed acetabular cavity. The defect will, 

 if due to defective development, be probably blastogenic in its 

 nature. There is, however, just the possibility that mal-nutrition 

 of the foetus in utero may be the cause. This is a large subject, 

 which will receive the attention it deserves in a separate and 

 subsequent section. 



* Trans. Path. Soc. xrii. p. 206. The author remarks that it has never been 

 explained why the malformation should so often aifect both acetabula and 

 occur more frequently in females. 



t Journ. of Anat. & Phys. vol. xiv. p. 368, 



X " Ueber die Ursachen der angebornen Hiiftgelenkverrenkungen," Vireh. 

 Arch. Bd. 74. S. 1 (1878). 



