MUSCLES OF THE TRUNK. 



247 



unites it to the mastoid tendon of the trachclo-mastoideas, and i)asses to the 

 mastoid crest. The second joins a very stronjj^ tendon common to the splenius, 

 the trachelo-mastoideus, and the mastoido-humeralis, which tendon is attached to 

 the transverse process of tiie atlas (Fig. 162, 'J). The two or three others 

 are directly inserted into the transverse processes of the third, fourth, and fifth 

 cervical vertehrie. 



Relations. — The splenius is related, outwardly, to the rhomboideus, the 



Fig. 159. 



BTTPERFICIAL MUSCLES OF THE NECK AND SPINAL REGION OF THE BACK AND LOINS. 



1, Dorsal trapezius; 2, longissimus dorsi ; 3, cervical trapezius ; 4. angularis scapulae; 5, splenius, 

 6, anterior, or superficial portion of the mastoido-humeralis; 7. its humeral insertion; 7', its 

 mastoid insertion; (?, the thin aponeurosis uniting this insertion to the sterno-maxillaris ; 8', 

 posterior jiorlion of the mastoido-humeralis; 9, its inferior aponeurosis inserted into the inter- 

 stice of the long abductor of the arm; 10, sterno-maxillaris; 11, suhscapuio-hyoideus ; 12, 

 portion of the cervical panniculus; 13, portioo of the great extensor of the forearm ; 14, posterior 

 belly of the long abductor of the arm ; 15, great pectoral muscle. 



angularis scapulse, cervical trapezius, and mastoido-humeralis ; inwardly, to 

 the complexus and the two oblique muscles of the head ; by its inferior border, 

 to the superior margin of the inferior branch of the longissimus dorei. 



Action. — It extends the head and neck in inclining them to one side. If the 

 two act in concert, the extension is direct. 



