43 6 APPENDIX. 



III. MUSCLES OF THE FORE LIMB. 



A. Muscles connecting the Arm with the Body. If the skin- 

 muscles have been dissected, as above, cut the cutaneus maximus 

 near its insertion, and reflect it toward the median dorsal line; in 

 this way remove it completely. Remove the platysma in the same 

 way. The first layer of body-muscles is thus exposed. 



If the skin-muscles are not to be dissected, these may be removed 

 with the skin. If the skin has not yet been removed, proceed as 

 follows: 



Beginning at the cranial end of the manubrium make two 

 incisions in the skin, one passing to the lambdoidal ridge and the 

 other to the spinous process of the thirteenth thoracic vertebra. 

 Raise the triangular flap thus formed, taking up the skin-muscles 

 with it. 



1. The trapezius group of muscles (pp. 115-117, and Fig. 68, 

 d, h, andy) is now exposed and may be dissected. Begin with the 

 spinotrapezius (Fig, 68, _/). Read the description of the muscle, 

 then raise its caudal border and work under it until its cranial border 

 is reached and the middle of its inner surface is free. Then transect 

 it, and reflect the two halves of the muscle toward the origin and 

 insertion, clearing the fat, etc. , from the inner surface of the muscle 

 and the parts covered by it. Determine origin and insertion. 



2. The acromiotrapezius (Fig. 68, h). Dissect in the same 

 manner, being careful not to injure the broad thin tendon which 

 connects the two muscles across the middle line. 



3. The clavotrapezius (Fig. 68, </). Separate it carefully, from 

 the cleidomastoid (p. 120). Transect and reflect, as before. 



4. The occipitoscapularis (Fig. 73, a, p. 149). Note the strong 

 fascia which separates it from the deeper muscles of the neck. Be 

 careful not to injure adjacent muscles in tracing this toward origin 

 and insertion. Transect. 



5. The rhomboideus. Transect. 



Recognize the levator scapulae ventralis (Fig. 68, _/"), the sterno- 

 mastoid (Fig. 68, c; Fig. 65, ^), and the cleidomastoid (Fig. 65, h). 

 Then dissect 



6. The levator scapulae ventralis (Fig. 68, _/"). Its origin (Fig. 

 72, c, c") cannot be seen at this stage and should be left until the 

 cervical muscles are dissected. Be careful in transecting this muscle 

 to separate it well from the cleidomastoid. Transect. 



7. The cleidomastoid (Fig. 65, h]. Its origin cannot be fully 

 seen at this stage. Transect. 



Make a midventral incision of the skin from the cranial end of 

 the manubrium to a point opposite the crest of the ilium. From the 

 caudal end of this incision make an incision to the root of the tail. 

 From the cranial end of the incision in the ventral middle line make 

 a cut around the base of the fore limb on its caudal side, thus con- 



