132 ANATOMY OF UPPER EXTREMITY, ETC.. 



The erector spinse, with its accessories and the complexus. are now 

 to be removed by dividing transversely the tendon of the former, close 

 to the sacrum, raising it from the inner side and turning it outward. 

 The muscles which remain to be examined, with the exception of the 

 sub-occipital group, will be left in a very ragged condition, and ob- 

 scured by the remains of the numerous tendons and fasciculi divided 

 in the removal of the dissected muscles. It is difficult to make a neat 

 preparation of them. 



The SEMI-SPINALIS MUSCLE consists of a thin and narrow 

 stratum of short muscular bellies with longer tendons, 

 which stretches from the second cervical vertebra to the 

 lower part of the dorsal region ; each bundle, arising from 

 a transverse process, is inserted into a spinous process, the 

 fibres being directed downward and outward. The upper 

 bundles are larger than the lower, and the number of them 

 varies in different subjects. Although continuous, the 

 upper four of these muscular bundles, those arising from 

 the transverse processes of the four upper dorsal and in- 

 serted into the spinous processes of the four upper cervical 

 vertebrae, have been named the semi-spinalis colli, and 

 the lower six, those arising from the transverse processes 

 of the six lower dorsal and inserted into the spinous pro- 

 cesses of the four upper dorsal and two lower cervical ver- 

 tebr;e, the semi-spinalis dor si. 



The MULTIFLDUS SPINSE lies to the inner side of and be- 

 neath the last-named muscles, and they must be removed 

 in order to see it in its full extent. It reaches from the 

 sacrum to the axis, and consists of a series of muscular 

 slips, filling the vertebral groove at the side of the spinous 

 processes. Each fasciculus arises from a transverse pro- 

 cess, and is inserted into the spinous process of the first 

 or second vertebra above ; the first slip arises from the 

 transverse process of the third cervical vertebra, and is 

 inserted into the spinous process of the axis ; the last slip 

 arises from the back of the sacrum, and is inserted into the 

 spine of the fifth lumbar vertebra. 



The LEVATORES COSTARUM are sometimes considered as 

 accessories of the external intercostal muscles ; triangular 

 in shape, they arise from the transverse processes of the 

 dorsal vertebrae, and are inserted between the tubercle and 

 the angle of the rib below. The inferior levatores some- 

 times pass over one rib, to be attached to the second below 

 them. There are twelve of these muscles on each side. 



Between the spinous processes of the cervical and lum- 

 bar regions may be found a series of small muscles called 



