MYOLOGY 37 



II. MUSCLES OF THE TRUNK 



The muscles of the trunk may be divided into 



A. Muscles of the thorax 



B. Muscles of the abdomen 



C. Lumbar muscles 



D. Muscles of the back 



E. Muscles of the tail 



F. Perineal musculature 



A . Muscles of the thorax 

 As here segregated, these number eleven, as follows: 



Mm. panniculus carnosus serratus magnus 



pectoralis superficialis levator scapulae 



pectoralis profundus posterior intercostales extern! 



pectoralis profundus anterior intercostales interni 



pectoralis abdominalis sternocostalis 

 subclavius 



M. panniculus carnosus (figs. 4, 29). Origin of this 

 muscle should, perhaps, be considered as non-integral with 

 the latissimus dorsi. Connection is continuous with the 

 latter, but in reality origin is largely tendinous and just 

 mediad to the biceps. The muscle diverges from the 

 axillary fossa with strongly developed fibers, joining its 

 fellow of the opposite side upon the midventral line at a 

 point slightly craniad to the xiphoid process of the sternum, 

 and upon the middorsal line at a point immediately dorsad 

 of the axillary fossa. The fibers disappear in the fascia 

 covering the posterior haK of the belly, the groins and the 

 gluteal region, and the lower back. Fibers again develop, 

 however, at the base of the tail. The muscle is strongest 

 near its origin and in its cranio-dorsal portion. Caudad it 

 is diflScult to decide just where the fibers cease. 



Jn Neotoma the panniculus is somewhat better developed 

 — stronger and more extensive — and the main portion 

 reaches well onto the base of the tail. In Teonoma it is 



