POSTERIOR CERVICAL NERVES. 367 



beneath the inferior oblique muscle to which it gives offsets, is directed 

 upwards through the complexus and trapezius to end on the occiput (p. 23). 



The branch of the third nerve (fig. 119, 3 ) supplies an offset to the in- 

 teguments of the neck ; and ascending to the head through the trapezius, 

 is distributed to the lower part of the occiput, internal to the great occi- 

 pital nerve. Usually this nerve joins the preceding both beneath, and 

 superficial to the trapezius. 



The posterior primary branch of the suboccipital or first spinal nerve 

 (fig. 119, J ) is very short, and appears in the interval between the recti 

 and obliqui muscles. In passing from the spinal canal it is placed between 

 the arch of the atlas and the vertebral artery. The following branches 

 radiate from its extremity: 



One enters the under surface of the complexus near the cranial attach- 

 ment. A slender branch is furnished to each of the small muscles bound- 

 ing the space in which the nerve is contained, viz., the rectus major and 

 minor, and the superior and inferior oblique : the offset to the last muscle 

 joins the inner branch of the second cervical nerve. Occasionally this 

 nerve gives a cutaneous branch to the occiput. 



Posterior cervical plexus. Sometimes there is an intercommunication 

 between the suboccipital nerve and the internal pieces of the next two 

 cervical nerves beneath the complexus ; this forms the posterior cervical 

 plexus of M. Cruveilhier. 



* In the dorsal region. The posterior primary branches of the dorsal 

 nerves are twelve in number, and appear between the transverse processes-. 

 Each divides into an internal and an external piece ; and these are distri- 

 buted after the same plan as in the neck. 



* The external pieces increase in size from the first to the last, and are 

 differently distributed above and below. The upper six or eight pass be- 

 neath the longissimus and its cervical prolongation, as far as the interval 

 between the longissimus and the ilio-costalis, and end by supplying these 

 muscles and the levatores costarum. The lower six or four have a similar 

 arrangement and distribution with respect to muscles ; but, after reaching 

 the interval between the ilio-costalis and the longissimus dorsi, they are 

 continued to the surface through the serratus and latissirnus muscles, nearly 

 in a line with the angles of the ribs. 



* The internal pieces decrease in size from above downwards, and are 

 directed inwards between the semispinalis dorsi and multifidus spinae mus- 

 cles ; offsets are supplied to the muscles between which they are placed. 

 The upper six become cutaneous along the sides of the spinous processes 

 by perforating the seratus, rhornboideus, and trapezius. The loioer six 

 are small in size, and end in the multifidus spinae muscle. 



* In the loins. The posterior primary branches of the lumbar nerves, 

 five in number, appear between the erector and multifidus spin*. In their 

 mode of dividing and general arrangement they resemble the dorsal nerves. 

 Cutaneous offsets are furnished by the external set of branches. 



* The external pieces enter the erector spinae, and supply it and the 

 small intertransverse muscles. The first three pierce the erector spinas, 

 and become cutaneous after perforating the aponeurosis of the latissimus. 

 The branch of the last nerve is connected with the corresponding part of 

 the first sacral nerve by an offset near the bones. 



* The internal pieces are furnished to the multifidus spinae muscle. 

 Near their origin they are difficult to find, in consequence of being con- 

 tained in grooves on the articular processes. 



