SOME NEURAL TERMS. 113 



either a bone or an orifice; the oblique cases and derivatives of 

 course distinguish them. Medulla has been applied to several 

 parts. Epiphysis may designate the end of a bone or a part of 

 the brain. Theoretically objectionable, the context commonly 

 frees homonyms from serious ambiguity. 



Idionym. A word which, at least in anatomy, refers to but 

 one part ; e.g., cerebellum, thalamus, chiasma, pans, insula. 



Idionyms by Recombination. Cornu posterius, as employed 

 by most anatomists, is a homonym, designating either a cavity 

 of the cerebrum or a feature of the myel (spinal cord). But 

 postcornu, as introduced by me in 1881, applies only to the 

 cerebral cavity, and is thus an idionym. 



Contextual Explicitness. For want of a better phrase, this 

 may refer to the possibility of employing terms that might be 

 ambiguous but for their association with others. A common 

 example is cord, which may be used in at least five senses, by 

 the neurologist, the laryngologist, the surgeon, the obstetrician, 

 and the embryologist. When an entire publication or section 

 of it refers to a group of organs of the same general character, 

 then the generic element of their polyonymic designations may 

 be often omitted and the specific alone employed; e.g., with 

 arteries, fissures, gyres, etc. Indeed, to be absolutely explicit 

 or idionymic in all cases would require many new names or the 

 addition of genitives or other qualifiers to many already existing. 



Locative Names. The location of a part is a general and 

 comprehensive attribute and, as remarked by Owen, " signifies 

 its totality without calling prominently to mind anyone particu- 

 lar quality, which is thereby apt to be deemed, undeservedly, 

 more essential than the rest." 



Prepositional Locatives. -- With these the qualifying prefix, 

 a preposition or adverb, indicates the location of a part rela- 

 tively to some other part, more important, more easily recognized, 

 or earlier designated. Praecuneus designates a cortical area just 

 " in front of " the cuneus. 



Adjectival Locatives. These indicate either the location of 

 a part within some general region or its membership of a 

 series. Vertebra tkoracalis designates a spinal segment in the 

 thorax. Commisstira anterior, cm. media, and cm. posterior 



