22 TOPOGRAPHICAL ANATOMY OF THE 



the semispiualis capitis will be easily recognised by its great size and 

 strength and by the fact that it is crossed obliquely by four or five 

 tendinous intersections. The origin of the muscle is from the spinous 

 processes of the second, third, and fourth thoracic vertebrae (in common 

 with the splenius), the transverse processes of the first six or seven 

 thoracic and the articular processes of the last five or six cervical 

 vertebrae. A strong tendon begins over the atlas and is inserted into 

 the occipital bone close to the attachment of the ligamentum nucha^. 



Dissection. — Make a tiaiisvcrse incision through the senii.spinalis 

 capitis about the middle of the neck, and sever its origin from the 

 thoracic spinous processes. This will allow the two parts of the muscle 

 to be turned downwards, and will expose certain underlying muscles. 



M. SPINALIS (et semispinalls) cervicts. — The origin (from the 

 first four thoracic spinous processes) and the greater part of the extent 

 of the spinalis dorsi et cervicis belongs to the dissector of the thorax, 

 but its insertion into the spinous processes of the last four or five 

 cervical vertebrae should be examined during the present dissection. 

 This insertion lies medial to the semispinalls capitis. 



Tlie dorsal branches of the cervical nerves from the third to the 

 eighth should be examined before any further dissection is conducted. 

 The branches of the third, 'fourth, fifth and sixth nerves form the 

 dorsal cervical iilexus, which lies between the semispiualis capitis and 

 the ligamentum nuchfe. From this plexus cutaneous nerves pass to 

 the skin in the neighbourhood of the mid-dorsal line. Other filaments 

 supply the adjacent muscles. 



The relatively small dorsal branches of the seventh and eighth 

 cervical nerves pass in a dorsal direction between the multifidus 

 cervicis and the longissimus cervicis, and end in the cervical rhomboid 

 muscle and the superjacent skin. 



M. MULTIFIDUS CERVICIS. — The multifidus - muscle of the neck 

 consists of five or six strons^ bundles arising- in succession from the 

 articular processes of the last four or five cervical and the first thoracic 

 vertebrse. Each bundle is divisible into two sets of fibres, the more 

 superficial of which pass obliquely in a cranial and medial direction to 

 be inserted into the spinous process of a cervical vertebra. The deeper 

 fibres are shorter in length and straisfhter in direction and are inserted 

 into the articular process of a vertebra. The last bundle is inserted into 

 the spinous process of the epistropheus. 



^ Multifidus (from rntdtns, many +fi7ukre, to cleave or split), [L.], cleft or 

 divided into many parts. 



