184 OUTLINES OF EQUINE ANATOMY. 



lower, attaclied to tlie inferior extremity of the external 

 surface of the ribs, is the serrated margin of obliquus ab- 

 dominns externus. Having cut through and dissected 

 back latissimus dorsi and trapezius, the operator must 

 show the posterior attachment of rhomboideus muscle, 

 which arises from the cordiform portion of the ligamentum 

 nuchse to within six inches of the occiput, and from the 

 continuation of it as far back as the sixth dorsal superior 

 spinous process, from which points it runs to become in- 

 serted into the venter surface of the cartilage of elongation 

 of the scapula, and to that bone above serratus magnus. 

 Now rhomboideus may be cut through, and the fore limb 

 (if not by this time separated) may be drawn downwards, 

 and serratus magnus traced to its inferior attachments. 

 We now see the small anterior serratus muscle running 

 from the anterior border of the ribs from the sixth to 

 twelfth become attached by tendinous expansion superiorly 

 to the superior spinous processes of the dorsal vertebrae 

 from the second to the thirteenth. By dividing the dorsal 

 and lumbar faschia and turning the serrati downwards 

 upon their inferior attachments we expose 



Transversalis eostarum, a thin, complex muscle, about 

 two inches broad, anteriorly attached to the transversa 

 process of the last cervical vertebra, in common with lon- 

 gissimus dorsi, and by small tendons attached to small 

 roughened surfaces on the posterior margin of all the ribs- 

 (in the first at the tubercle). By muscular attachments it 

 is connected to the anterior margin of the ribs as high up 

 as their tubercles. Posteriorly it becomes attached to the 

 transverse processes of the anterior lumbar vertebrae. Its 

 internal surface rests on the external intercostals, while its 

 superior margin is in direct contact, and almost blends 

 with 



Longissimus dorsi. This is, posteriorly,, an immense 

 fleshy mass situated at the posterior part of the back and 

 on the upper surface of the lumbar vertebrae ; it is the 

 largest muscle in the horse's body, and is attached to thet 

 crista of the ilium, extending from the antero-inferior 

 to the supero-posterior spinous j^i'ocess, and occupying a 

 slight portion of its venter surface, whereby it become?? 

 attached to the sacro-iliac ligament and the transverse 

 oblique and superior spinous process of the first and second- 

 sacral bones, and extends backwards into the triangular 



