J ? 6 ATLAS AND TEXT-BOOK OF HUMAN ANATOMY. 



scalenus medius and the levator scapulae, and is inserted by a short tendon into the upper border 

 of the second rib. Its insertion is covered by the upper digitations of the serratus anterior. 



There is occasionally present a small independent muscular fasciculus situated between the 

 scalenus anterior and medius. It is known as the scalenus minimus, and is inserted into the first 

 rib and also into the dome of the pleura. 



^ . J?" SC t Cni Tt V V h t i : er T SUPply ParUy fr ° m the Cervical P lexus and P artlv ( the scal enus posterior) from small 

 special branches of the brachial plexus. They elevate the two upper ribs. 



THE PREVERTEBRAL CERVICAL MUSCLES. 



The muscles of the prevertebral group (Figs. 258 and 259) are situated to the inner side 

 and above the scaleni, from which they are separated by the transverse processes of the cervical 

 vertebrae. They are the longus colli, the longus capitis, and the rectus capitis anterior 



The longus colli (Fig. 259) is a rather thin flat muscle which is situated between the cervical 

 viscera and the bodies of the upper thoracic and of all of the cervical vertebrae. Its upper and 

 outer portion is covered by the longus capitis, and between the two muscles and to either side of 

 the median line there is a space, the width of the little finger, in which may be seen the anterior 

 longitudinal ligament of the vertebral column. The muscle has the form of a very obtuse-an-led 

 triangle, the obtuse angle being placed at the transverse process of the sixth cervical vertebra 



It is composed of three portions, each of which constitutes a side of the triangle The inner 

 portion is the longest, and extends from the body of the third thoracic vertebra to the axis It 

 arises by tendinous slips from the bodies of the upper thoracic and the lower cervical vertebra 

 and inserts, partly by muscular and partly by tendinous tissue, into the bodies of the upper cervical 

 vertebra. The upper and outer portion arises by flat tendinous digitations from the anterior 

 tubercles of the transverse processes of the upper cervical vertebra and is inserted into the anterior 

 tubercle of the atlas, this portion being sometimes termed the longus atlantis, and also into the 

 bodies of the underlying cervical vertebra in common with the inner segment of the muscle The 

 lower and outer portion arises from the lateral surfaces of the bodies of the upper thoracic 

 vertebra and is inserted by the tendinous slips into the transverse processes of the lower cervical 

 vertebrae. 



The longus capitis (rectus capitis anterior major) (Figs. 258 and 2 S9 ) is a rather broad flat 

 muscle the upper portion of which is somewhat thickened. It lies to the outer side of the lon«nis 

 colli and covers its upper and outer segment, and arises by distinctly separated tendinous 

 digitations from the anterior tubercles of the transverse processes of the third to the sixth 

 cervical vertebra. From these origins it passes upward and slightly inward, and is inserted 

 into the lower surface of the basilar portion of the occipital bone. There is a distinct aponeu- 

 rosis upon the anterior surface of the muscle somewhat above its middle. 



rervi J 1 "' LTI "f "* ^ ,0ngUS ^^ ™ "H*" *>' S P edal branches of the ce ™cal plexus. Thev bend the 

 mull vertebra column anteriorly, and, when they act unilaterally, turn the head toward the side of the contracting 

 muscle. In the turning movement, the longus capitis and the upper and outer segment of the longus colli act together 



