374 



THE ANATOMY OF THE HORSE. 



of the tail there are three muscles, viz., one above, one below, and one 

 at the side. There are also three arteries — one on the middle line 

 below, and one between the inferior and lateral muscles on each side. 

 On each side there are two sets of nerves, one of which accompanies the 

 lateral artery, while the other is on the upper aspect of the bones, 

 between the lateral and superior muscles. [Besides the three muscles 

 now to be described, there is the compressor coccygis already dissected 

 (page 355)]. 



The Erector Coccygis (sacro-coccygeus superior). This muscle arises 



Fig. 54. 



Muscles of the Tail, deep Muscles of the Hip, and Pelvic Ligaments (Chauveau). 



1. Erector coccygis ; 2. Curvator coccygis ; 3. Depressor coccygis ; 4. Compressor coccygis ; 

 5. Deep gluteus ; t>. Rectus parvus ; 7. Common tendon of obturator internus and pyriformis ; 

 8. Gemelli ; 9. Accessory fasciculus of the same ; 10. Quadratus femoris ; 11. Sacro-sciatic ligament ; 

 12. Great sacro-sciatic foramen ; 13. Superior ilio-sacral ligament ; 14. Inferior ilio-eacral ligament. 



from the sides and summits of the sacral spines, and it is inserted by 

 successive short tendons to the upper aspect of the coccygeal vertebrae. 



Action. — Acting with its fellow, to elevate the tail directly; acting 

 alone, to elevate the tail and incline it laterally. 



The Curvator Coccygis (sacro - coccygeus lateralis). This muscle 

 seems to continue backwards the semispinalis of the loins. It arises 

 from the last two lumbar spines and from the spines of the sacrum, 

 and it is inserted into the lateral aspect of the coccygeal bones. 



Action. — To bend the tail to the side of the acting muscle. 



The Depressor Coccygis. Anteriorly this muscle consists of an 

 outer and an inner portion, sometimes described as separate muscles. 

 It arises from the lower face of the sacrum, beginning about the 3rd 

 foramen. The slips of the inner portion are inserted into the first six 



