THE ANTERIOR LIMB 259 



(d) The trapezius. Origin in two portions. Superior (cervical) 

 portion. External occipital protuberance and dorsal liga- 

 ment of the neck (ligamentum nuchae). Insertion: Meta- 

 cromion and supraspinous fascia. Inferior (thoracic) 

 portion. Origin: Spinous processes of the thoracic verte- 

 brae and the lumbodorsal fascia. Insertion: Dorsal half 

 of the scapular spine. The muscle forms a broad triangular 

 sheet on the dorsolateral surface of the shoulder. 



The levator scapulae major, basioclavicularis, and 

 trapezius should be divided. 



On the ventrolateral surface of the superior portion of the trapezius 

 and levator scapulae major ma}^ be found nerves from the ventral rami 

 of the third, fourth, and fifth cervical spinal nerves. The great auri- 

 cular nerve (n. auricularis magnus) passes from the third to the ear, 



(e) The rhomboideus minor. Origin: Ligamentum nuchae. 

 Insertion: Anterior two-thirds of the vertebral border of 

 the scapula. 



(/) The levator scapulae minor. Origin: Mastoid and supra- 

 occipital portions of the skull. Insertion: Medial surface 

 of the inferior angle of the scapula. 



(g) The rhomboideus major. Origin : Spinous processes of the 

 first seven thoracic vertebrae. Insertion: Posterior third 

 of vertebral border. The rhomboidei are almost continuous. 

 By dividing the rhomboidei, the scapula may be dis- 

 placed laterad. The operation is facilitated by dividing 

 the latissimus dorsi, the relations of which should, however, 

 first be noted (2, a). 



(h) The serratus anterior consists of two portions. Cervical 

 portion : Origin on the transverse processes of the posterior 

 five cervical vertebrae and the anterior two ribs. Insertion 

 on about the anterior four-fifths of the medial surface of 

 the vertebral border of the scapula. Thoracic portion: 

 Origin on the third to the ninth ribs by separate slips 

 alternating with those of the external oblique. Insertion 

 on the posterior two-fifths of the medial surface of the 

 vertebral border of the scapula, overlapped medially by 

 the cervical portion and the levator scapulae minor. 



