The Vertebral Musculature. 269 



(b) The scalenus medius. Origin: Transverse process of the 

 fifth cervical vertebra. Insertion: Lateral surfaces of the 

 third to fifth ribs. 



(c) The scalenus posterior. Origin : Transverse processes of 



the fourth to sixth cervical vertebrae. Insertion: First rib. 



The medius is superficial; the anterior more or less separated frcm 

 the posterior by the origin of the cervical portion of the s^rratus anterior. 



(d) The scalenus medialis. Origin: The sternum at the 



point of attachment of the first rib. Insertion : Middle of the 



ventral portion of the first rib. 



The foregoing muscles comprising the scalenus group, are destroyed 

 by the removal of the ventral thoracic wall (p. 255). 



(e) The longUS colli. Origin: Bodies of the first six thoracic 

 vertebrae. Insertion : The muscle passes forward on the 

 ventral surface of the bodies of the vertebrae, giving off 

 insertion fibres, and also receiving strands of origin. It 

 terminates on the anterior tubercle of the atlas. 



(f) The longus capitis is partly fused with the foregoing 

 muscle, but its origin is in a more lateral position from the 

 transverse processes of the first six cervical vertebrae. 

 Insertion: Sphenooccipital synchondrosis. 



(g) The longus atlantis. Origin : Lateral to the longus capitis, 

 from the transverse processes of the third to sixth cervical 

 vertebrae. Insertion: Transverse process of the atlas. 



The longus capitis should be divided near its insertion. 



(h) The rectus capitis anterior. Medial portion of the 

 ventral surface of the transverse process of the atlas. In- 

 sertion: Basioccipital bone. 



The caudal musculature in the rabbit comprises, in addition to 

 the posterior extension of the cutaneus maximus, the following axial 

 muscles: 



(a) The extensor caudae medialis. It lies in the furrow 

 between the spinous and articular processes of the posterior sacral 

 and anterior caudal vertebrae, and is inserted on the transverse 

 processes and dorsal surfaces of the caudal vertebrae. 



(b) The abductor caudae posterior lies in the groove between 

 the articular and transverse process and is inserted on succeed- 

 ing vertebrae. It appears to continue the multifidus, but corres- 

 ponds to the more medial portion of the longissimus. 



