PELVIC REGION 443 



tho heads of tlie last three ribs, and from tlie bodies of the three last dorsal 

 and all the lumbar vertebra?. Insertion — into the brim of the pelvis. Action 

 — to assist the last muscle in rounding the back. 



Iliacus is situated in the; iliac fossa. Orhjin — from the crest of the ilium 

 external to the sacrum, from the venter and anterior spinous process. 

 Insertion — with the psoas magnus into the trochanter minor internus of the 

 femur. Action — to ilex the haunch. 



PELVIC REGION 



Several muscles are attached to the pelvis : 1st, for the control of the 

 anus ; 2nd, for the genital organs, and accelerating the flow of urine ; 3rd, 

 for the movements of the tail. 



Retractor ani is a funnel-shaped layer of thin muscular fibres arising 

 within the pelvis, and inserted into the margin of the anus. Action — to 

 prevent the anus from being forced outwards by the expulsive efforts of the 

 abdominal muscles. 



Sphincter ani is attached above to the coccyx, and encircles the anus 

 with fleshy fibres, which serve to close it. 



Cremaster is a thin layer of muscle which is attached to the yellow 

 fascia covering the abdomen, and to the internal oblique, from which it 

 descends upon the spermatic cord after it passes through the extei^nal 

 abdominal ring, and is inserted into the fibrous covering of the testicle. 



The muscles of the penis, vagina, and clitoris have no general interest; 

 they are, erector penis, triangularis penis, and accelerator urime, in the 

 male ; and sphincter vaginte and erector clitoridis in the female. 



The coccygeal muscles are described as in four sets, erector, depressor, 

 curvator, and compressor coccygis, the names of which bespeak their 

 actions. They all arise from the pelvis and pelvic ligaments, and are 

 inserted into the corresponding sides of the bodies and transverse processes 

 of the coccygeal bones. 



MUSCLES OF THE FORE EXTREMITY 



The muscles of the fore extremity are classed in three divisions — 

 viz. those of the shoulder, arm, and leg. In the two first of these great 

 confusion exists, in consequence of the different names given to them by 

 English and French veterinary writers. Percivall only enumerates twelve, 

 while Chauveau gives fifteen ; ■*■ the former not considering the long 

 extensor of the fore-arm as a distinct muscle, but as a part of the triceps. 

 The scapulo humeralis posticus (or grele of Chauveau) is omitted alto- 

 gether by Mr. Percivall, though quite a distinct muscle, and playing 

 a most important part in supporting the capsular ligament of the 



^ Chanveaii's arrangement is now generally accepted. For the detailed anatomy 

 of the muscles see McFadyean's Anatomy of the Horse. 



