572 



HUMAN ANATOMY. 



Variations. — The origin may extend to the transverse processes of all the cervical ver- 

 tebrae, and may be continued upon the mastoid process above and upon the upper ribs below. 

 Slips may occur connecting the levator with various neighboring muscles, the most interesting 

 of these connections being that with the serratus magnus, since comparative anatomy shows 

 that the levator was primarily continuous with that muscle. 



A separated portion of the outer part of the muscle is occasionally inserted into the outer 

 end of the clavicle, forming what is termed the levator claviculcs. 



3. Rhomboideus Minor (Fig. 559). 



Attachments. — The rhomboideus minor is a band-like muscle which arises 

 from the lower part of the Hgamentum nuchae and from the spinous process of the 



Fig. 558. 



Serratus posticus superior 



Levator anguli scapulae 



Superior angle of scapula 

 Supraspiiiatus 

 Coracoid process 

 Tendon of supraspinalus \ 

 Acromion 

 process 



Scalenus posticus 

 Scalenus niedius 



Lesser, 

 tuberosity of 

 humerus 



Subscapularis 



Serratus mag- 

 nus, upper, 

 middle, and 

 lower por- 

 tions 



Latissimus dorsi, cut edge 



Externa, 

 oblique 



Dissection of thoracic wall, showing serratus magnus; clavicle has been removed and scapula drawn outward. 



last cervical vertebra and passes laterally and downward to be inserted into the ver- 

 tebral border of the scapula at the base of the spine. 



Nerve-Supply. — By the dorsal scapular nerve from the fifth cervical nerve. 



Action. — To draw the scapula upward and medially, at the same time rotating 

 it so that the lateral angle is moved downward. 



4. Rhomboideus Major (Fig. 559). 



Attachments. — The rhomboideus major immediately succeeds the rhom- 

 boideus minor, and is a quadrilateral sheet which arises from the spinous processes 

 of the four upper thoracic vertebrae and from the intervening interspinous liga- 



