COMPLEXUS AND SEMISPINALES MUSCLES. 237 



transversalis cervicis continued up from the longissirnus ; 7, ilio-costalis (sacro- 

 lumbalis), drawn slightly inwards to show the slips of insertion into the lumbar 

 fascia and the various ribs ; inside the costal insertions are seen the origins of the 

 accessorius; 7', the ascendens cervicis continued upwards from the accessorius ; 8, spinalis 

 dorsi. On the right side, 6 marks, in the lumbar region, the insertions of the longis- 

 simus dorsi into the upper four transverse processes (the insertion into the accessory pro- 

 cesses not being shown), in the dorsal region the narrower tendons of insertion into the 

 lower part of the dorsal transverse processes (the six lower only are represented); 6', the 

 series of insertions into nine ribs; 7, the ilio-costalis drawn outwards; 7', placed between 

 the lowest costal insertion of the ilio-costalis and the lowest origin of the accessorius ; 

 7", extension of the ascendens cervicis from the fifth rrb towards the neck ; 9, 9, semi- 

 spinalis colli; 10, 10, semispinalis dorsi; 11, 11, lower dorsal and lumbar parts of 

 the multifidus spinse, which appears again above the semispinalis colli, above the upper 

 9 ; 12, placed upon the eighth rib, levatores costarum, long and short ; 13, in the upper 

 part of the figure points by four lines to the rectus capitis posticus minor, rectus major, 

 obliquus superior, and oWiquus inferior muscles. 



COMPLEXUS AND TRANSVERSO-SPINALES. The muscles of the complicated 

 group comprising the complexus semispinalis, and multifidus spince, present 

 the feature in common of ascending with an inward inclination, and are 

 thus distinguished from those last described. The most superficial, the 

 complexus, not usually included in this group, but obviously resembling the 

 others, has the longest and most vertical fibres, but is the shortest as a 

 whole, being limited to the upper dorsal and the cervical region ; the muscle 

 beneath it, the semispinalis, occupies the greater part of both these regions ; 

 while the multifidus spinse, extending from the sacrum to the axis, has the 

 shortest and most oblique fibres. 



The complexus (complexus major} arises by tendinous points from the 

 transverse processes of the seven highest dorsal and the seventh cervical verte- 

 brae, and from the articular processes of four and sometimes five other cer- 

 vical vertebrae, together with the capsular ligament uniting them ; and it is 

 inserted into the large internal impression between the two curved lines of 

 the occipital bone. It is narrower above than below, and its inner margin 

 in the neck is in contact with the ligamentum nuchse. Above the middle 

 the muscle is partly crossed by a tendinous intersection. One interrupting 

 tendon in particular, on the inner side, is so constant that the fibres con- 

 nected with it, viz. , those ascending from the three or four lowest points of 

 origin, are often described separately, under the name of biventer cervicis : 

 this portion of the muscle is also frequently connected by a tendinous slip 

 with one or two of the spinous processes belonging to the last cervical or 

 first dorsal vertebra. 



The complexus muscle is covered by the splenius, except at its lowest origins from 

 the dorsal vertebrae and at the internal portion of its upper extremity ; the trachelo- 

 mastoid and transversalis cervicis rest upon its series of origins, and the semispinalis 

 colli, the posterior recti, and the obliqui capitis, together with the deep cervical artery, 

 are concealed by it. 



The semispinalis muscle consists of fibres exkn ling from transverse pro- 

 cesses to spines, each bundle crossing over about five vertebrae. It arises 

 from the internal tubercles of the transverse processes of numerous dorsal 

 vertebrae, usually the ten highest, and is inserted into spines from the axis 

 to the fourth dorsal vertebra inclusive. It is described in two parts. 



a. The semispinalis colli is the part under cover of the complexus. It arises 

 from, the upper four or five dorsal transverse processes, and is inserted into 

 the spines of the cervical vertebrae from the second to the fifth inclusive, being 

 thickest at its insertion into the second vertebra. 



