Muscles of the Back. 



287 



Diaphragma (pars costalis) 



Insertion of the ni. latissimus dorsi 



Costa XII 



Iu>;ertion of the 

 m. serratus posterior inferior 



M. serratus posterior inferior 



I Mm. intercostales exteriii 



I I 



I I Mm. intercostales interni 



M. transversus abdominis I 

 Crista iliaca 



Proc. transversus 

 I 1 vert, lumbalis IV 

 ! M. sacrospinalis 

 ' (cut through) 



P'ascia himbodorsalis 

 (anterior laj'er) 



1 J M. obliquus internus 



j I abdominis 



I Tendon of origin 



I of the m. transversus abdominis 



Fascia himbodorsalis (posterior layer) 



332. Muscles of the lumbar 



viewed from behind. 



region (2^ layer), 



(The mm. kitissimus dorsi and obhquus extemus abdominis have been removed on both sides: on the 

 left side the mm. obliquus internus abdominis and serratus posterior inferior have also been removed.) 



[Text see also p. 288.] 



M. levator scapulae (O.T. levator ang-uli scajjulae) (see Figs. 299 301 and 330). Form: 

 flatly roimded, oblong. Position: on the lateral surface of the neck, covered by the mm. sterno- 

 cleidomastoideus and trapezius, in front coming in contact with the m. scalenus posterior, behind 

 with the m. sjilenius capitis et cervicis. Origin: by four tendinous processus from the posterior 

 tubercles of the transverse processes of the l^t 4th cervk'al vertebra (see Figs. 306 and 335). 

 Insertion: the fibers run parallel downward, backward and lateralward to the margo vertebraUs 

 scapulae. Action: it draws the shoulder-blade medianward and upward and rotates it so that 

 the angulus inferior is turned medianward ; when the shoulder-blade is fixed, it bends the cervical 

 portion of the spine to the same side and rotates it somewhat. Innervation: n. doi'saiifrscapulae. 



Trlgonum lumbale [Petiti] (O.T.Petit's triangle) (see Fig. 331), a triangular thiimer spot 

 of the posterior abdominal wall, varying in size; below it is bounded by the crista iliaca, lateralward 

 by the posterior margin of the m. o))liquus extemus abdominis, medianward by the lateral margin of 

 the m. latissimus dorsi. In this triangle the muscle fibers of them, obliqims internus are visible; in 

 front of them lies the tendon of origin of the m . tran sversus abdominis and of the m. quadratus liimborum. 



Fascia uuchae (not represented in the figure) is a thin membrane of connective tissue 

 which lies just beneath the mm. trapezius aud rhomboidei; it goes off from the inferior surface 

 of the squama occipitahs , covers the mm. splenii capitis et cervicis and seraispinalis capitis, 

 is connected medianward with the lig. nuchae, is continued in front into the fascia colli and 

 goes over below at the m. serratus posterior superior into the fascia lumbodorsalis. 



1<J* 



