330 report — 1846. 



will ensure their permanence ; but the course of anatomical science having 

 unfolded the primary form which is the basis of those modifications, there 

 arises the same necessity for giving utterance to ideas of the generic cha- 

 racter of the parts by general terms. 



Inasmuch, however, as the different segments of the human skeleton de- 

 viate in various degrees from the common archetype, and as the different 

 elements of such segments differ in their modifiability, anthropotomy has at 

 no period wanted also its ' general terms ' expressive of the recognised ex- 

 tent of such conformity : such terms also, indicating, obscurely indeed, so 

 much perception of the pre-existing model as could be obtained from the 

 study of one form, at a period when that form — the human frame — was 

 viewed as something not only above, but distinct from, if not antithetical 

 to the structures of the brute creation, and when it was little suspected 

 that all the parts and organs of man had been sketched out, in anticipation, 

 so to speak, in the forms of the inferior animals. Thus the word ' vertebra ' 

 shows, by the number of the segments or parts of segments to which it is 

 applied in anthropotomy, the recognition of the obvious extent to which the 

 archetype is retained in such primary constituents of the human endoskeleton. 

 And, inasmuch as in some regions (the cervical, e.g.) the ' vertebra ' includes 

 all the elements of the typical segment, there developed, it has been retained, 

 but, with a more definite meaning, as the technical term of the primary 

 constituent segment of the endoskeleton in all vertebrate animals. 



The ' true vertebrae ' of anthropotomy are those segments which retain the 

 power of moving upon each other ; and the term is applied in a peculiar aud 

 empirical sense very different from the meaning which the anatomist at- 

 taches to a true or typical vertebra. The ' false vertebrae ' of anthropotomy 

 are those segments or parts of segments forming the lower or hinder extreme 

 of the endoskeleton, and which do not admit of reciprocal motion at their 

 joints. And Monro, admitting that the condition of even the human os 

 coccygis sometimes militates against the definition, meets the objection by 

 arguing for the speciality of that bone, and with as good or better reason 

 than those who have subsequently contended against admitting the cranial 

 segments into the category of vertebrae. "From the description of this bone " 

 (os coccygis), " we see how little it resembles vertebrae ; since it seldom has 

 processes, never has any cavity for the spinal marrow, nor holes for the pas- 

 sage of nerves*." 



Embryology has since demonstrated that the parts of the os coccygis are 

 originally in vertebral relation with the neural axis; and that this is subse- 

 quently withdrawn by a concentrative movement, which in like manner 

 withdraws it from the terminal segment at the opposite extreme of the endo- 

 skeleton. The homology of the divisions of the sacrum with the true ver- 

 tebrae is admitted by Monro, because of the perforations for the nerves : and 

 this character is still retained in the nasal vertebra in the form of the cribri- 

 form foramina, although its ueurapophyses, like those of the sacrum, have 

 lost their primitive relation to the neural axis. 



Homological anatomy, therefore, teaches, that the term ' vertebra' should 

 not only be applied to the segments of the human skeleton in the technical 

 and definite sense illustrated by figs. 14 and 15, but be extended to those 

 modified and reciprocally immoveable segments which terminate the endo- 

 skeleton superiorly, and are called collectively ' skull.' 



The term ' head,' then, indicates a region of specially modified vertebrae, like 

 the terms ' neck,' ' chest,' ' loins,' <S:c. ; and amongst the species of the primary 

 segments characterized by specific modifications, the ' cranial ' vertebrae must 



* Monro, I. c. p. 143. 



