546 



HUMAN ANATOMY. 



{d) THE OBLIQUUS MUSCLES. 



1. Scalenus anticus. 3. Scalenus posticus. 



2. Scalenus medius. 4. Rectus capitis lateralis. 



5. Intertransversales anteriores. 



I. Scalenus Anticus (Fig. 542). 



Attachments. — The anterior scalene (m. scalenus anterior) arises by lour 

 tendinous slips from the anterior tubercles of the transverse processes of the third 

 to the sixth cervical vertebrae. The four slips unite to form a rather fiat muscle 

 which extends downward and forward to be inserted into the scalene tubercle on the 

 upper surface of the first rib. 



Fig. 542. 



Complexus 

 Splenius 



Levator anguli scapulae 



Sterno-mastoid, stump 

 •Rectus capitis anticus major 



Subscapularis 



Serratus magnus, 

 middle portion 



Scalenus anticus 

 Scalenus medius 



Scalenus posticus 

 Rhomboidei 



^Sternum 



I rib 



Serratus magnus, upper portion 

 Dissection of right side of neck, showing scalene and adjacent muscles. 



Nerve-Supply. — By branches from the fourth, fifth and sixth cervical nerves. 



Action. — To bend the neck forward and to the same side and to rotate it to 

 the opposite side. If the cervical vertebrae be fixed, it will then raise the first rib, 

 assisting in inspiration. 



Relations. — The anterior scalenus lies in front of the roots of the brachial 

 plexus, and near its insertion it passes over the second portion of the subclavian artery 

 and under the subclavian vein. The phrenic nerve rests upon its anterior surface 

 during its course down the neck. 



2. Scalenus Medius (Figs. 541, 542). 



Attachments. — The middle scalene is situated behind the scalenus anterior. 

 It arises by six or seven tendinous slips from the transverse processes of the lower 

 six or of all the cervical vertebrae and extends downward and outward to be inserted 



