TRANSACTIONS OF SECTION D. — DEFT. ANATOMY AND PHYSIOLOGY. 605 



2. On a Direct Method for determining the Calorific Power of Alimentary 

 Substances. By J. A. Wankltn and W. J. Cooper. 



3. On the Aberrant Form of the Sacrum connected with Naegele's Obliquely 

 Contracted Pelvis. By Allen Thomson, M.D., LL.D., F.B.S. 



Dr. Allen Thomson exhibited a well-marked specimen of Naegele's obliquely- 

 contracted pelvis in a male adult, together with a series of eight sacrums present- 

 ing different forms and degrees of the abnormal development which is the most 

 frequent primary cause of the pelvic deformity first described by Naegele. 



Naegele's first description of this deformity was published in 1834 (' Heidel- 

 berg. Klinisch. Annalen,' vol. x. No. 4, translated in the ' London Medical and 

 Surgical Journal/ vol. vii. No. 168), but he had already observed a case of it as 

 early as 1803, and others in 1813 and 1825. In 1850 Naegele published at 

 Maintz a separate and more extended memoir on the obliquely contracted 

 pelvis, and some other pelvic deformities, illustrated with full-sized representa- 

 tions, in which he showed that the oblique deformity in question is not confined 

 to one sex, but occurs iu the male as well as in the female ; though, of course, its 

 presence in the female is more liable to arrest attention from its relation to diffi- 

 culties in parturition. 



Although Naegele had not fully described the nature of the abnormal condition 

 of the sacrum which accompanies the pelvic deformity, yet he had figured that 

 condition clearly as it occurred in different instances on the right and on the left 

 side, and it may be inferred from his description and drawings that in the majority 

 of the cases the deformity was of the nature of a congenital malformation. Dr. 

 Edmund B. Sinclair, of Dublin, had the merit of detecting the existence of a 

 similar deformity during life in a case which he has described in the 'Dublin 

 Journal of Medical Science.' In this case Dr. Sinclair was inclined to attribute 

 ' the origin of the obliquity to morbid degeneration in the vicinity of the sacro- 

 iliac articulation, and he may have had sufficient reasons for doing so. But the 

 specimens exhibited to the section by Dr. Thomson fully bear out the view recog- 

 nised by Rokitansky, that the deformity of oblique pelvis is very frequently if not 

 always of the nature of an aberrant kind or defect of development occurring in 

 the first sacral vertebra ; and Dr. Thomson's object was to show more clearly than 

 had previously been done the nature of this aberration. 



The most common form of the malformation may be described as one in which 

 the first sacral vertebra presents on one side all the usual characters which belong 

 to it as a constituent part of the sacrum — possessing, therefore, the large lateral 

 mass which enters into the formation of the upper pelvis, and articulates with the 

 ilium iu the auricular surface ; while upon the opposite side there is no sacro-iliac 

 junction, an entire absence of the lateral mass, and the first sacral vertebra pre- 

 sents in its transverse and articular processes, its intervertebral foramen, the 

 form of its body and arch, and in all other respects, the characters of a lower 

 lumbar vertebra. There is, therefore, half a sacral vertebra on one side and half 

 a lumbar vertebra on the other ; the detachment of the vertebral arch (laniinas and 

 processes), however, generally extending over to the sacral side. 



The obliquity of form in the pelvis, and its consequences in other parts of 

 the vertebral column, are most directly the result of the unequal support given by 

 the sacro-iliac articulations of opposite sides. The author regards the liga- 

 mentous synostosis frequently found in these cases at the sacro-iliac articulation 

 on the abnormal side, not, as has been supposed by some, as a cause of the deformity, 

 but rather as a consequence of the greater strain thrown upon this joint by the 

 curvature following upon the shrunken condition of the first sacral vertebra, and 

 the absence of its connection with the ilium in the nonsymmetrical pelvis. 



Of the eight specimens of sacrums exhibited, three presented the lumbar form 

 in the upper piece on the right side, and four on the left side, while one was nearly 

 symmetrical in form, but presented a partial retrogression, as it were, from the sacral 

 to the lumbar form on both sides very nearly in an equal degree. 



