156 



THE ANATOMY OF THE HORSE. 



Action. — The right and left muscles, acting together, flex the head. 

 When only one muscle acts, it inclines the head to the same side. 



The Scalenus (Plate 3 and Fig. 18). This muscle is situated on the 

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



Fig. 18. 



LiClAMENTUM NUCH^ AND DEEP MUSCLES OF THE NeCK {ChaUVnav). 



1. Lamellar jjortion of the ligamentuni nxichse ; 2. Funicular portion of the same ; 3. SemispinaliB 

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

 posticus minor ; 7. Obliquus capitis inferior ; 8, Obliquus capitis superior ; 0. Intertransversales 

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

 the scalenus. 



of the last four cervical vertebrse. 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 inserted 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 

 inspiration. When the rib becomes the fixed point, the muscles will 

 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- 



