Muscles of the Back. 



IV. 



YT, 



IX. i 



XI. 



xs. 







224. The Long Muscles 

 of the Back. 



M. erector trunci sen spinae. Orig. : 

 Posterior surface of the sacrum, tuber- 

 osity, and posterior portion of the crest 

 of the ilium, spinous processes of the 

 lumbar vertebrae. 



Opposite the last rib this muscle 

 divides into the : 



a) M. sacrolumbalis which is at- 

 tached by twelve tendinous slips into 

 the twelve ribs ; from the six or seven 

 lower ribs accessory bundles arise 

 (M. accessor ius ad sacro-lumbalem) . The 

 analogous bundles of the five or six 

 upper ribs unite to form the M. cervi- 

 calis ascendens, which is inserted into the 

 transverse processes of the 6. 4. cer- 

 vical vertebrae. 



b) M. longissimus dor si which is 

 attached by ten tendinous slips at the 

 tubercles of the ribs (except the I. 

 and XII.) and the transverse processes 

 of the dorsal vertebrae. Its continuation 

 is the M. transversalis cervicis ; this 

 muscles arises from the transverse pro- 

 cesses of the four upper dorsal and two 

 lower cervical vertebrae, and is inserted 

 into the transverse processes of the five 

 upper cervical vertebrae. ("Acting on 

 both sides they extend the spinal column, 

 acting on one side they produce lateral 

 flexion and rotation of the column.) 



MM. levatores cost-arum (Fig. 225). 

 Orig. : Transverse processes of the 

 7. cervical to the XI. dorsal vertebrae. 

 Insert. : Each to the rib below. At 

 the lower ribs are the Levatores cost-arum 

 lonyi, which are inserted in the second 

 rib below their origin. 



j\f. liventer cervicis. Orig. : By three 

 or four tendinous slips from the trans- 

 verse processes of the upper dorsal 

 vertebrae; the middle of the muscle is 

 tendinous; above the 6. cervical vertebra 

 it again becomes fleshy (Inscriptio ten- 

 dinca) and is inserted below the superior 

 curved line of the occipital bone. (Draws 

 the head backwards.) 



