vni PREFACE. 



ventral. Medial refers to that side of the limb which in the 

 normal position is toward the middle of the body ; lateral to 

 the outer side. Terms of direction which are derived only from 

 the structure of the limb itself are in some cases more conven- 

 ient than the usual ones. In the fore limbs the terms radial 

 (referring to the side on which the radius lies) and ulnar 

 (referring to the side on which the ulna lies) are used ; in the 

 hind limbs the terms tibial and fibular are used in a similar 

 manner. Distal means toward the free end of a limb or other 

 projecting structure ; proximal, toward the attached end. 



For all these terms an adverbial form ending in -ad has 

 been employed. Experience has shown this to be very useful 

 in practice, and while not expressly recommended by the BNA, 

 it is not condemned. Terms ending in -al are therefore 

 adjectives ; those ending in -ad are adverbs. 



In compounding these terms of direction, the hyphen has 

 been omitted in accordance with the usage recommended by 

 the Standard Dictionary. Thus dorsoventral is written in 

 place of dorso-ventral, etc. The student will perhaps be 

 assisted in understanding these compounds if he notes that 

 the first component always ends in -<?, so that the letter o prac- 

 tically serves the purpose of a hyphen in determining how the 

 word is to be divided. 



In one particular the BNA nomenclature is not entirely 

 consistent. While recommending or at least permitting the 

 use of the general terms dorsal and ventral in place of the 

 human posterior and anterior, and cranial and caudal in place 

 of superior and inferior, it retains the words anterior, posterior, 

 superior, and inferior as parts of the names of definite organs. 

 For example, we have the muscle serratus anterior in place 

 of serratus ventralis; serratus posterior inferior in place of 

 serratus dorsalis caudalis. This is very unfortunate, from a 

 comparative standpoint, but we have felt it necessary to retain 

 the BNA terms in order that the structures of the cat may 

 receive the same names as the corresponding structures of 

 man. 



In the matter of orthography we have endeavored to follow 

 the best English anatomical usage, as exemplified in Gray's 



