DISSECTION OF THE PELVIS. 



361 



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

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

 (page 343).] 



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

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

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



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

 alone, to elevate the tail and incline it laterally. 



The Ctjrvator 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. 



, C 



>■"**. 











Fig. 48. 



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



1 Erector cocoytds ; 2. Curvator coccygis; 8. Depressor coccygis; 4. Compressor coccygis; 

 <; -hee-n eluteus- 6 Rectus parvus; 7. Common tendon of obturator internus and pynformis; 

 s Ppmelli- 9 Accessory fasciculus of the same ; 10. Quadi'atus f emoris ; 11. Sacro-sciaticligament ; 

 12. Great sjicro-sciatio foramen ; 18. Superior ilio-sacral ligament ; 14. Inferior ilio-sacral ligament. 



The Depressor Coccygis. Anteriorly this muscle consists of an 

 outer and an inner portion, which Leyh describes 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 

 coccygeal vertebrte, while the outer portion extends to the extremity of 

 the tail, and is provided with strong tendons of insertion. 



j^gfjn. It inclines the tail laterally or depresses it, according as it 



acts alone or with the opposite muscle. 



