MUSCLES OF THE THORAX — MUSCLES OF THE TAIL 325 



spines and the median rajihe of the neck, and is inserted into the occipital crest and 

 mastoid process. 



The complexus is composed of two parts — the biventer cervicis and the com- 

 plexus major proper. The biventer cervicis arises from the transverse processes 

 of the fifth and sixth, and the spines of the second to tlie fifth (or sixth) thoracic 

 vertebrae, from the ligament um nuchas, and the median raphe. It has four ten- 

 dinous intersections. The complexus major arises on the transverse processes of 

 the first three or four thoracic vertebra; and the articular processes of the last five 

 cervical. Both end on a strong common tendon which is inserted into the occipital 

 crest and the depression below it. 



The trachelo-mastoideus consists of two unequal portions. The large dorsal 

 part (M. longissimus capitis) arises on the transverse processes of the first four thor- 

 acic and the articular process of the last three or four cervical vertel)ra;, and ends 

 with the splenius on the mastoid process of the temporal bone. The small ventral 

 part (M. longissimus atlantis) arises on the articular processes of the third, fourth, 

 and fifth cervical vertebrae, and ends on the wing of the atlas. 



The other muscles present no striking differential features,but it may be noted 

 that distinct interspinales are present. 



Muscles of the Thorax 



There are twelve pairs of levatores costarum. 



The external intercostals do not occuj^y the spaces between the costal carti- 

 lages. 



The diaphragm has a small tendinous center. The oesophageal opening is 

 between the pillars. The fleshy rim is attached at the costo-chondral junctions 

 from the eighth backward, and along the thirteenth rib nearly its entire length. 



MUSCLES OF THE BACK AND LOINS 



The serratus anticus arises from the median raphe of the neck and the first 

 six or seven thoracic spines, and is inserted into the second to the ninth ribs. 

 It is well developed. The serratus posticus — much weaker — arises on the lumbo- 

 dorsal fascia, and is inserted into the last three or four ribs. Thus one or two ribs 

 intervene betw^een the two. 



The transversalis costarum (Ilio-costalis) is well developed, and extends from 

 the ilium to the sixth, fifth, or fourth cervical vertebra. 



The longissimus resembles that of the other animals, but the spinalis et 

 semispinalis separates clearly at the sixth or seventh thoracic vertebra. It is 

 inserted into the articular and spinous processes of the last six cervical vertebrae. 

 It has no depression in the lumbar region for the gluteus medius. 



The intertransversales are fleshy, as in the ox. 



The interspinales are distinct, especially in the lumbar region. 



Muscles of the Tail 



These present the same general arrangement as in the horse. The sacro- 

 coccygei, however, arise on the luml)ar vertel)rie also, and the coccygeus on the 

 ischiatic spine. There is found a sacro-coccygeus accessorius, which arises on the 

 internal border of the ilium, the edge of the sacrum, and the transverse processes 

 of the first coccygeal vertebrae, and is inserted between the superior and lateral 

 sacro-coccygei. It is homologous with the intertransversales. 



