160 



THE ANATOMY OF THE HORSE. 



side of the lower half of the neck. It arises from the transverse processes 

 of the last four cervical vertebrte. In front of the 1st rib it is perforated 

 by the roots of the brachial plexus, which there divide it into an upper 

 and a lower portion. The first of these is much the smaller of the two, 

 and it is i?iserfed into the outer surface of the 1st rib near its upper end. 

 The lower portion is inserted into the anterior border and outer surface 

 of the same rib, the lowest fibres being immediately above the smooth 

 impression left on the anterior border of the bone by the axillary vessels. 

 Action. — To pull forwards or fix the 1st rib, and thus to aid in 



^ .. --^^ 



-^ I 



Fig. 20. 



LiGAMENTUM NUCH.E AND DEEP MuSCLES OF THE NeCK (ChauveO-U). 



1. Lamellar portion of the ligamentum nuch^ ; 2. Funicular portion of the same ; 3. Semispiualis 

 of the back and loins ; 4. Semispinalis colli ; 5. Rectus capitis posticus major ; 6. Rectus capitis 

 posticus minor ; 7. Obliquus capitis inferior ; S. Obliquus capitis superior ; 9. Intertransversales 

 colli; 10. Rectus capitis anticus major ; 11. Exterrml intercostals ; 12. Upper and lower divisions of 

 the scalenus. 



inspiration. When the rib becomes the fixed point the muscles flex the 

 neck or incline it to the side, according as the right and left muscles 

 act in concert or singly. 



The LoNGUS Colli (Plate 28). This muscle clothes the inferior face 

 of the spinal column from the 6th dorsal vertebra to the atlas, the 

 right and left muscles being closely united along the middle line, while 

 at its outer edge each muscle is partially blended with the intertrans- 

 verse muscles. The dorsal portion of the muscle is seen in the 

 dissection of the thorax (Plates 22 and 25), where its fibres take origin 



