WORK PRELIMINARY TO DISSECTION 4 1 



to the spinal column, and the tip of the nose is craniad to the 

 spinal column and craniad to the cranium. Also, curiously 

 enough, if the tail of the rabfiit is flexed onto its body, the last 

 caudal vertebra is caudad to the next to the last caudal vertebra 

 which in turn is craniad to the last caudal vertebra, just as if 

 the tail were extended straight out from the body. 



D. MYOLOGICAL TERMS 



Muscles are spoken of as being '^voluntary," the striated or 

 skeletal muscles; or ''involuntary," the nonstriated pale or 

 smooth muscles. Involuntary muscles occur chiefly in the 

 walls of tubes, such as blood vessels and the digestive tract, 

 while most all of the other muscles are striated. Striated or 

 skeletal muscles are attached to bones or other muscles by 

 tendons. The terms ''voluntary" and "involuntary" are 

 misleading, for all "voluntary" muscles are subject to some 

 form of involuntary action, such as reflex movements of the 

 hmbs and automatic, or purely involuntary, acti\dty such as 

 occurs in the "voluntary" muscles which have to do with 

 swallowing and those which have to do with respiration. 



The origin of a muscle is its more central or fixed or, in case 

 of muscles of the extremities, the end attached nearest the body, 

 while the insertion of a muscle is the distal or movable attached 

 end. However, these terms are more or less arbitrary, for they 

 are true in point of function only when the origin is fixed. 

 Thus, if the muscles of the head and neck are contracted so that 

 the head is fixed, contraction of the basioclavicular muscle (No. 

 4, p. 49) will draw the shoulder craniad and thus will conform 

 to the definition of the terms origin and insertion. Contrarily, 

 if the muscles which attach the shoulder to the body are 

 contracted in such a way as to fix the shoulder, while the head 

 is not fixed, then contraction of the basioclavicular muscle 

 will move the head but not the shoulder. Thus, it is apparent 

 that these are dogmatic terms, the use of which is intended as a 

 means of saving time in readily referring to one of two ends of a 



