Muscles of the Back. 



295 



340. Short muscles of the back (S'^'^ layer), viewed from behind. 



Mm. levatores costarum. Form. Hat, tri- 

 angular, thin. Position: behind the articulationes 



costotransversariae , covered by 

 Origin: procc. transversi of 

 the Tth cervical and 1st nth 

 thoracic vertebra . Insertion: 

 lateralward and downward to 

 the next rib below (mm. leva- 

 tores costarum breves) ; in the 

 3 4 lower intercostal spaces 

 also to the next rib but one 

 below (mm. levatores costarum 

 longi). The}' are directly ad- 

 jacent to the mm. intercostales 

 externi. Action: they extend 

 the spinal column, incline it 

 toward the same, and rotate it 

 toward the opposite side. In- 

 nervation: ramus posterior of 

 the n. cervicalis Vni and rami 

 anteriores [nn. intercostales] of 

 the nn. thoracales I XL 

 Mm. interspiuales, short 



the ni. 



longissimus 



Protuberantia 

 occipitalis externa 



Processus mastoideus 



Tuberculum 

 posterius atlant 



Processus spinosus 

 vertebrae cervicalis VII 



_ Jr. rectus capitis 

 posterior minor 



Costa 



- M. rotator 

 brevis 



Costa VI 



Proc. spill, 

 vertebrae ^ 

 thoracf. VI 



bundles between every two 

 neighboring spinous processes ; 

 from the epistropheus to the 

 saciHim. They are often double 

 on the cervical vertebrae, are 

 usually absent from the thoracic 

 vertebrae but very powerful on 

 the lumbar vertebrae. Action: 

 they bend the spinal column 

 backward. Innervation: 

 , rami mediales of the rami 

 posteriores of the nn. cervicales 

 III VIII, thoracales I XII 

 and lumbales I Y. 



Mm. iutertrausversarii 

 (O.T. intertransversales), short 

 bundles between every -two 

 neighboring transverse pro- 

 cesses. They are usually absent 

 from the thoracic vertebrae. 

 They are double on the cervical 

 vertebrae, extending between 

 adjacent tiibercida anteriora 

 (mm. intertransversarii an- 

 teriores) and also between 

 adjacent tubercula posteriora 

 (mm. intertransversarii poste- 

 riores). They are double also 

 on the lumbar vertebrae extend- 

 ing between the procc. marail- 

 lares (mm. intertransversarii 

 mediales) and between the procc. 

 (mm. intertransversarii laterales). 

 they bend the spinal cohunn to 

 Innervation: direct branches of the plexus 

 cervicalis and brachialis; rami anterior(>s [nn. 

 intercostales] of the nn. thuracales: rami la- 

 terales of the rami posteriores of the nn. lum- 

 bales I V. 



Processus 

 spinos. vert, 

 tliorac. XII 



Costa XI t 



-M. transversus 

 abdominis 



M. iiiterspinalis 



Proc. 



spinosus 



vertebrae 



lumb. V 



Os sacrum 



transversi 

 Action: 

 the side. 



Pelvis 



M. rotator 

 longus 



M. levati 

 costae bn 



M. levati 

 costae loii 



Ligamentun 

 lumbocostal 



jSI. inter- 



transvers. no 



Fascia lumbc 



(Fusion of 



layers) 



M. iiifertrans 



lateralis 



Fascia luni 



~ fiorsalis 



(anterior la; 



JI. rotate 



longus 



M. rotate 

 brevis 



