144 THE ARTISTIC ANATOMY OF ANIMALS 



But as, on the other hand, this fasciculus is in relation 

 with the triceps, we shall in preference consider it in relation 

 witli this latter (see p. 173). 



The aponeurosis by which the great dorsal arises from 

 the vertebral column covers, as in man, the muscles which 

 occupy the grooves situated on each side of the spinous 

 processes — the spinal muscles or common muscular mass, 

 if we regard them as a whole (Fig. 70, 7) ; the sacro-lumbar 

 and the long dorsal muscles covering the transverse spinal, 

 if we consider them as distinct. 



It would be superfluous to enter here into a detailed 

 examination of these muscles. 



If they are but little developed the spinous processes 

 become prominent under the skin ; if they are more so they 

 may by their thickness project beyond the level of these 

 processes, and these latter thus come to lie in a groove more 

 or less marked, which, on account of the division which is 

 determined by its presence, has caused the regions which 

 it occupies to be designated by the names double hack and 

 double loins. 



The muscles are extensors of the vertebral column. 



Under the aponeurosis of the great dorsal muscle there is 

 found in man another muscle, the serratus posticus inferior, 

 which, on account of being deeply placed and its slight 

 thickness, offers nothing of interest in connection with 

 the study of external form. It arises from the spinous 

 processes of the three last dorsal vertebrce and those of 

 the three first lumbar ; it then passes upwards and out- 

 wards, and divides into four digitations, to be inserted into 

 the inferior borders of the four last ribs. We repeat that 

 it is covered by the great dorsal muscle. 



In the pig, ox, and horse, which have this latter muscle 

 less developed in its posterior portion, the same small 

 serratus muscle, known as the posterior serratus, is visible 

 in the superficial layer of muscles (Fig. 6g, 6 ; Fig. 70, 6). 

 The number of its digitations is more or less considerable 

 according to the species examined. 



The Rhomboid Muscle (Fig. 70, 21). — In order to 

 make intelligible the position of the rhomboid in the super- 



