WORK PRELIMINARY TO DISSECTION 43 



Make a midventral incision through the skin from the larynx 

 to about one inch of the anus. Starting at a point on this 

 incision midway between the arms, cut through the skin along 

 the medial side of the right arm to a point just beyond the 

 elbow where the forearm is completely encircled by the incision. 

 Now, beginning at a point on the midventral incision near the 

 region of the navel make an incision through the skin dorsad 

 to the vertebral column. Each one of these incisions through 

 the skin should be as nearly straight as possible and should 

 be at right angles to the preceeding one. Crooked incisions 

 will detract from the neatness of the dissection and increase 

 the difficulties encountered in replacing the reflexed skin at the 

 close of each laboratory period. It will be necessary to cut 

 through the subcutaneous muscles. Without making addi- 

 tional incisions through the skin reflex this delimited portion 

 of the skin so as to expose the muscles of the right shoulder, 

 neck, and side of the thorax. The skin of the right hand and 

 distal two-thirds of the antibrachium will remain, thus forming 

 a ''glove" protecting the muscles and tendons of the forearm, 

 wrist, and hand from drying rapidly, while the other three- 

 quarters of the rabbit will remain unskinned until these regions 

 are to be dissected. Do not loosen the skin on any other region 

 of the body at this time, for if left in place it will greatly 

 retard dessication, and too, a fresh surface is much easier to 

 dissect than an old, dirty one. Before leaving the laboratory 

 be certain to apply some of the glycerine — gum mixture to the 

 skinned areas, to replace the skin, wrap the specimen in muslin 

 and place it in the receptacle provided for that purpose. 



G. SUBCUTANEOUS MUSCLES 



The major portion of the two subcutaneous muscles is usually 

 removed with the skin. On account of the thin structure and 

 diffuse nature of insertion the subcutaneous muscles are gener- 

 ally difficult to study. The largest of these muscles is the 

 cutaneous maximus which arises principally from the latissimus 



