384 



THE SUBCLAYIAX ARTERY. 



passes along the roots of the spinal nerves, supplj-ing the spinal cord and its 

 membranes, and anastomoses with the other spinal arteries ; the other branch 

 ramifies on the back part of the bodies of the vertebrae in the same manner as 

 similar branches derived from the intercostal and lumbar arteries. 



(/y) J/w,<tc-«/rt/' branches of variable size are distributed to the deep-seated cervical 

 muscles. 



B. Cranial branches : 



((/) The jHitttcrlor mrningi'al artery is a small branch which arises opposite the 

 foramen ma^um. and ramifies between the dura mater and the bone in the 

 occipital fossa, and upon the falx cerebelli. There are sometimes two of these 

 small vessels. 



(h) The jmsfcrwi' spinal ai-teiy, arising at an obtuse angle from the vertebral, 

 inclines backwards round the medulla oblongata to reach the back part of the 

 spinal cord ; aided by reinforcements from small arteries which ascend upon tlie 

 cervical and dorsal nerves through the intervertebral foramina, it may be traced 

 along the cord, lying behind the roots of the nerves, as a minute tortuous vessel. 

 or rather a series of little inosculating vessels, as far as the second lumbar vertebra,, 

 where it terminates iu ramifications on the cauda equina. 



Fig. 256. Fig. 256. — Deep Dis- 



^_^ SECTION OF THE SUB- 

 CLAVIAN Artery on 



THE RIGHT SIDE, SHOW- 

 IKa THE ORIGIN AND 

 COURSE OF THE VER- 

 TEBRAL Artery (from. 

 Tiedemann). ^ 



a, Upper part of the 

 sterno-inastoid muscle, its- 

 clavicular part divided 

 bolow ; h, spinous process 

 of the axis ; c, superior 

 oblique muscle ; d, placed 

 on the inferior oblique 

 muscle, points by a line 

 to the posterior arch of 

 the atlas vertebra ; f, 

 semispinalis colli ; /, 

 placed on the longus 

 colli, points to the trans- 

 verse iiroccss of the sixth 

 cervical vertebra ; (/, on 

 the first rib, points to- 

 the scalenus anticus mus- 

 cle cut near its attach- 

 ment ; 1, innomin.ate 

 artery ; 2, right common 

 carotid ; 3, right sub- 

 clavian ; below it, the 

 origin of the internal 

 mammary artery ; above 

 it, 4, the thyroid axis, 

 its branches cut short ; 

 5, vertebral artery, pass- 

 ing up through the can.al 

 of tlie transverse pro- 

 cesses and giving branches 

 to the muscles ; 5', placed 

 on the rectus major, points to its horizontal part on tb* arch of the atlas ; 6, placed on 

 the lower part of the divided scalenus medius, points to the trunk of the deep cervical 

 artery ; 7, occipital artery emerging from below the stcrno-mastoid and other muscles 

 attached to the mastoid process. 



