////: />'.-/ r A'. 



Erector Spinae and Branches. Remove the vertebr.il apnneur.>sis ( l-' 

 2S2) and expose the fifth layer of muscles and its subdivisions. (V\^. 283.) 



Com plexus 



Splcnius capitu 



Spleniua colli 



Serratus poeticua superior 



Vertebral aponeurosis 



Serratus postiouB 

 inferior 



ObliquuB Intern UB 



Origin of latiasimuB 

 durai 



SEVENTH CERVICAL VERTEBRA 



TWELFTH THORACIC VERTEBRA 



FIFTH LUMBAR VERTEBRA 



FIG/ 282. THE THIRD AND IMTKTM LAYKRS OF mi: MUSCLES OF THE U.\. i 



Origin. (i) The spines of the two last thoracic, all the lumbar, and the four 



upper sacral vertebrae ; (2) the back of the side portion of the fourth sacral 



