22 THE NECTURUS 



MUSCLES OF THE SHOULDER GIRDLE 



Drawing 8. Make a drawing X 3 of the shoulder girdle, showing 

 the attachment of the muscles. 



The muscles are very clearly separated and require little 

 dissection for demonstration. With a blunt instrument, 

 make the necessary separation to show the origins and 

 insertions. Use the right side for this work. 



Latissimus dorsi 

 Find the humerus and scapula for use as landmarks. Ex- 

 tending posteriorly and dorsally to the midline of the back 

 is a large, fan shaped muscle, the latissimus dorsi. De- 

 termine its function by manipulating it in order to see its 

 action on the humerus. 



DORSALIS SCAPULA 



This vertical, scapular muscle is immediately anterior 

 to the latissimus dorsi. It is band like with an extensive 

 origin on the scapula and suprascapula. It is inserted on 

 the humerus. 



Cucullaris 



This muscle is inserted along the anterior edge of the 

 scapula and suprascapula, anterior to the dorsalis scapulae. 

 It has a double origin from the fascia of the midline of 

 the back. 



Omohyoid 



The omohyoid is ventral to the cacullaris and extends 

 diagonally forward. It originates in the epibranchial 

 region and is inserted on the procoracoid, just posterior to 

 the scapula. 



Rectus superficialis hypobranchialis posterior 

 This muscle is inserted on the procoracoid. It originates 

 on the myocommata and proximal end of the first epibran- 



