Muscles of the Back. 



289 



334. Broad muscles of the back (S'^kyer), viewed from behind. 



(The shoulder-blades and the muscles going to thera have been removed.) 

 3E. serratiis posterior 



Protiiberantia 

 occipitalis _ 



externa 



Processus 

 iiiastoideus 



Processus spinosiis 

 vertebrae oervicalis Vli 



M. semispinalis capitis 



]M. splenitis capitis 



et cervicis 



scaleni 



serratus posterior 

 superior 



Processus 



spinosus 



vertebrae 



tlioracalis IV 



Costa VI 



superior (O.T. serratus ])usticu 

 superior). Form: flat, qua- 

 . drangular, very thin . Position: 

 upper part of the back, covered 

 by the mm. rhomboidei. Origin: 

 by a flat tendon from the lig. 

 michae or the spinous processes 

 of the 6^li and 't^ cervical and 

 1 St and 211'^ thoracic vertebrae. In- 

 sertion: the fibers run parallel, 

 obliquely lateralward and down- 

 ward and terminate by four fleshy 

 digitations on the 2nd 5th rib. 

 Action: it elevates these ribs. 

 Innervation: rami anteriores 

 [nn. intercostales] of the nn. 

 thoracales I IV. 



M. serratus posterior in- 

 ferior (0. T. serratus posticus 

 inferior) (see also Fig. 331). 

 Form: flat, quadrangular, very 

 thin. Position: lower part of 

 the back, covered by the m. la- 

 tissimus dorsi and partly also by 

 the m. trapezius. Origin: po- 

 sterid^- layer of the fascia lumbo- 

 dorsalis in the region of the 

 10tli_i-2tli thoracic'and the 1st 

 and 2Jid lumbar vertebrae. In- 

 sertion: the fibers run parallel 

 obliquely lateralward and upw;ird 

 tind terminate by lour fleshy di- 

 gitations on the"^ 9<ii 12'h rib. 

 Action: it draws these ribs 

 downward and outward; it con- 

 tracts on inspiration. Inner- 

 vation: rami anteriores [nn. in- 

 tercostales] of the nn. thora- 

 cales IX XII. 



M. splenius capitis (see 

 also Figs. 296, 301, 330 and 335). 

 For m : flat, oblong-quadrangular, 

 thick. Position: in the neck, 

 partly covered by the mm. trajjc- 

 zius and sternocleidomastoideus, 

 serratus posterior superior ;nid 

 rhomlx)idei. Origin: lig. nucbne 



at the level of the 3r'<i 7tii cervical vertebra as well as from the spinous processes of the 

 1st and 2nd thoracic vertebrae. Insertion: the fibers converge somewhat and i>ass upward 

 lateralward by a thick, short tendon to the proc. mastoideus and to the linea nuchae superior 

 OSS. occipitahs. Action: it rotates the head so that the face is turned upward and toward thi' 

 same side; the muscles of the two sides together bend the head backward. Innervation: 

 rami laterales of the rami posteriores of the nn. cervicales II VIII. 



M. splenius cervieis (0. T. splenius colli) (see Figs. 296, 3;i0 and 335). Form: flat, 

 'jlduug-quadrangular, narrow. Position: it forms in a way a continuation downward of the 

 preceding muscle and is often indistinctly separable from it. Origin: procc. spinosi and ligg. 

 interspinalia of the 3r'i 6*11 thoracic vertebra. Insertion: by 23 processes to the tubercula 

 posteriora of the procc. transversi of the 23 uppermost cervical vertebrae. Action: it bends 

 the neck backward and lateralward and rotates the atlas like the preceding muscle rotates the 

 head. Innervation: like that of the preceding muscle. 



Processus 



spinosus 



vertebrae 



thoracalis' 



XII 



Costa XII 



Fascia 

 Uimbn- 

 dorsalis 



Mm. inter- 

 costales 

 extern! 



iSf. serratus 

 posterior 

 inferior 



I'ascia 

 umbodorsali 



M. 

 transversus 

 abdominis 



