THE MUSCULAR SYSTEM. 145 



and spinous process of the vertebrae above; action, preserves the 

 erect condition of the. spine; nerves, internal branches of the 

 posterior divisions of the cervical, dorsal, lumbar, and sacral 

 nerves. 



ROTATORES SPINJE. Eleven on either side. Origin, from 

 upper part of transverse process; insertion, into outer surface 

 and lower border of the laminae of the vertebrae above, from the 

 first and second dorsal to the eleventh and twelfth; action, ro- 

 tates the spinal column; nerves, anterior branches of the pos- 

 terior divisions of the dorsal. 



SUPRASPINALES. Origin and insertion, the spinous proc- 

 esses in the cervical region of the vertebrae; action, extends 

 cervical spine; nerves, internal branches of the posterior divi- 

 sions of the cervical. 



INTERSPINALES. Consist of muscular bands in pairs be- 

 tween the spinous processes of the adjoining vertebrae : six pairs 

 in the cervical region, three pairs in the dorsal, four or five in the 

 lumbar; action, extend the spine; nerves, internal branches of 

 the posterior divisions of the cervical, dorsal, and lumbar. 



EXTENSOR COCCYGIS. Origin, from the first piece of the 

 coccyx, or last bone of the sacrum ; insertion, into the lower ex- 

 tremity of the coccyx; action, rudimental in man. 



INTERTRANSVERSALES. Are small, muscular bands between 

 the transverse processes: in the cervical region seven pairs, in 

 the dorsal twelve pairs, in the lumbar region four pairs; action, 

 flex the spine laterally ; nerves, internal branches of the posterior 

 division of the cervical, dorsal, and lumbar. 



RECTUS CAPITIS POSTICUS MAJOR. Origin, from the spi- 

 nous process of the axis; insertion, into inferior curved line of 

 the occipital bone; action, rotates the atlas and the cranium; 

 nerve, the suboccipital. 



RECTUS CAPITIS POSTICUS MINOR. Origin, from the tu- 

 bercle of the posterior arch of the atlas; insertion, below the 

 inferior curved line of the occipital bone; action, draws the 

 head backward; nerve, suboccipital. 



OBLIQUUS CAPITIS INFERIOR. Origin, spinous process of 

 the axis ; insertion, lower back portion of the transverse process 

 of the atlas; action, rotates the atlas and the cranium; nerves, 

 suboccipital and great occipital. 



OBLIQUUS CAPITIS SUPERIOR. From upper surface of the 

 transverse process of the atlas; insertion, between the curved 

 lines of the occipital bone to the outer side of the complcxus; 

 action, rotates the atlas ; nerves, suboccipital and great occipital. 



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