THE FASCIA AND MUSCLES OF THE TAIL 



239 



Insertion. — The dorsal surface of the coccygeal vertebriB. 



Action. — Acting together, to elevate (extend) the tail; acting singly, to elevate 

 and incline it laterally. 



Structure. — The muscle has a strong rounded belly. It is inserted by means of 

 short tendons which fuse with those of the next muscle. 



Relations. — Superficially, the coccygeal fascia; internally, its fellow; later- 

 ally, the sacro-coccygeus lateralis; deeply, the vertebrae 



3. Sacro-coccygeus lateralis (M. sacro-coccygeus dorsalis lateralis; curvator 

 coccygis). — This muscle lies im- 

 mediately lateral to the preced- 

 ing. 



Origin. — The sides of the 

 sacral spines, with the multifi- 

 dus, and the transverse processes 

 of the sacral and coccygeal ver- 

 tebrae. 



Insertion. — The lateral sur- 

 face of the coccygeal vertebrae, 

 except the first four. 



Action. — Acting with its fel- 

 low, to assist the preceding mus- 

 cle in elevating the tail; acting 

 singly, to incline it to the same 

 side. 



Structure. — This muscle ap- 

 pears to be a direct continuation 

 of the multifidus dorsi . The belly 



38 



Fig. 182. — Cross-section of Tail of Horse 

 Close to Anus. 

 34, Coccygeal vertebra; 35, sacro-coc- 

 cygeus superior; 36, intertransversalis; 37, 

 sacro-coccygeus inferior; 38, coccygeus; S9, 

 recto-coccygeus; 40, coccygeal fascia. (After 

 Ellenberger-Bauni, Anat. fiir Kiinstler.) 



Fig. 183. — Muscles of Perineum of Horse. 

 «, Coccygeus; b, retractor ani; c, c', sphincter ani e.xter- 

 nus; d, recto-coccygeus; e, sacro-coccygeus inferior lateralis; 

 /, retractor penis; g, bulbo-cavernosus; h, ischio-caveriiosus; 

 /, internal pudic artery; k, anus; I, penis. (After EUenberger- 

 Baum, Top. Anat. d. Pferdes.) 



is fusiform and receives reinforcing fasciculi from the transverse processes of the 

 sacrum. This is succeeded by bundles of tendons, as many as four lying alongside 

 of each other. 



Relations. — Superficially, the lateral sacro-iliac ligament and the coccj'geal 

 fascia; dorsally, the sacro-coccygeus superior; ventrally, the intertransversales; 

 deeply, the vertebrae and a branch of the lateral coccygeal artery and accompanying 

 vein and nerve. 



4. Intertransversales caudae (Mm. intertransversarii caudae). — These con- 

 sist of muscular l)uii(lles which lie on the lateral aspect of the tail, between the 

 preceding muscle and the sacro-coccygeus inferior. They begin on the lateral edge 



