260 



Muscles of the Neck. 



..::i^ 



Processus spinosus 

 epistrophei 



Tendinous slips of 



he in. levator scapulae 



(cut througli) 



[. scalenus raedius 



alenus anterior 



nus posterior 



i spino 

 tebrae 

 is VII 



scalenus 

 inlmus 



Atlas 



306. Mm.scaleni 

 of the right side, 



vieAved from the ri^ht. 



Corpus 



vertebrae 



cervicalis VH 



M. scalenus anterior (0. T. 



scalenus anticus) (see also Figs. 

 299 301 and 304). Form: flat, 

 oblong-quadi'angular. Position: 

 close to the inferior part of the 

 cervical spine. Origin: by four 

 tendinous slips from the trans- 

 verse processes of the 3'''3 to the 

 6*11 cervical vertebra. Inser- 

 tion: downward and forward by 

 means of a short tendon to the 

 tuberculura scaleni [Lisfranci] of 

 the 1st rib. Action: when the 

 cervical spine is fixed it elevates 

 the 1st rib; -jvhen the l^t rib is 

 fixed it bends the cervical spine 

 forward and lateralward ; and 

 when acting with its fellow of the 

 opposite side the two bend the 

 cervical spine directly forward. 

 I n n e r V a t i n : direct branches of 

 the cervical and brachial plexuses. 

 M. scalenus medius (see 

 also Figs. 299301 and 304). 

 Form: flat , oblong- triangular. 

 Position: close to the taferior 

 part of the cervical spine, behind 

 the m. scalenus anterior, sepa- 

 rated from it at the pt rib by 

 a triangular space. Origin: 

 by 6 (7) slips from the trans- 

 verse processes of the 6 (7) in- 

 ferior cervical vertebrae. In- 

 sertion: downward and lateral- 

 ward to the lateral suiface of 

 the l^t rib (behind the sulcus 

 subclaviae). Action: when the 

 cervical spine is fixed it elevates 

 the 1 ^t rib ; when the 1 **t rib is 

 fixed it bends the cervical spine 

 lateralward and forward. I n n e r- 

 V a t i n : direct branches of the 

 cervical and brachial plexuses. 



M. scalenus posterior (0. T. 

 scalenus posticus) (see also Figs. 

 299301 and 304). Form: flat, 

 oblong-quach'augular. Po si t i on : 

 close to the inferior part of the 

 cervical spine, bounded in front by the m. scalenus medius, behind by the m. iliocostalis cervicis, 

 lateralward by the m. levator scapulae; usually fused with the m. scalenus medius. Origin: 

 by 23 slips from tiie transverse processes of the 2 or 3 inferior cervical vertebrae. Insertion: 

 downward and lateralward to tlie lateral surface of the 'l'^^^ rib. Action: is related to the 2c' rib as 

 is tliat of the preceding muscle to the l^t rib. Innervation: direct branches of the brachial plexus. 

 M. scalenus minimus (inconstant). P'orm: flatly rounded, narrow. Position: in 

 the slit between the nun. scalenus anterior and medius; it separates the brachial plexus from the 

 a. sulx^lavia. Origin: by 1 2 slips from the transverse processes of the 6ti or of the 

 6'1> and 7"i cervical vertebra. Insertion: downward and forward to the lateral surface of the 

 l*<t rib and to the pkuiral cupola. Action: makes the pleural cupola tense. Innervation: 

 direc^t branches of the brachial plexus. 



Tuberculum scaleni 



. .. Costa I 



Costa II 



for the passage 

 e a. subclavia 



Tuberositas eostae 



