1020 



THE NERVE SYSTEM 



the Rectus capitis posticus major, the Obliquus superior and Obliquus inferior; 

 it gives branches also to the Rectus capitis posticus minor and to the Complexus. 

 From the branch which supplies the Inferior oblique a communicating filament 

 is given off which joins the second cervical nerve. This nerve also occasionally 

 gives off a cutaneous filament, which accompanies the occipital artery and com- 

 municates with the occipitalis major and minor nerves. 



The posterior division of the second cervical nerve is much larger than the 

 anterior division, and is the largest of all the posterior cervical divisions. It 

 emerges from the vertebral canal between the anterior arch of the atlas and lamina 

 of the axis, below the Inferior oblique. It supplies a twig to this muscle, and 

 receives a communicating filament from the first cervical. It then divides into 

 an internal or medial and an external or lateral branch. 



The internal or medial branch, called, from its size and distribution, the great 

 occipital nerve (n. occipitalis major) (Fig. 753), ascends obliquely inward between 

 the Obliquus inferior and the Complexus, and pierces the latter muscle and the 

 Trapezius near their attachments to the occipital bone. It is now joined by a 

 filament from the posterior division of the third cervical nerve, the anastomotic, 

 and, ascending on the back part of the head with the occipital artery, divides 

 into two branches, which -supply the integument of the scalp as far forward as 

 the vertex, communicating with the occipitalis minor. It gives off an auricular 

 branch to the back part of the ear and muscular branches to the Complexus. 



The external or lateral branch is often joined by the external branch of the pos- 

 terior division of the third cervical nerve, and supplies the Splenius, Trachelo- 

 mastoid, and Complexus. 



GREAT OCCIPK 

 TAL NERVE 



RCCTUS CAPITIS 

 LATERALIS 



ANTERIOR PRIMARY DIV! 

 8ION OF FIRST CERVICAL 



POSTERIOR PRIMARY DIVI- 

 SION OF FIRST CERVICALl 



OBLIQUUS 

 SUPERIOR 



RANCH TO COMPLEXUS OUT 

 VERTEBRAL ARTERV 



POSTERIOR PRIMARY DIVISION 

 OF FIRST CERVICAL 

 ANASTOMOTIC BRANCH 



ANASTOMOTIC 

 THIRD CERVICAL 



OBLIQUUS 

 INFERIOR 



FIG. 753. Posterior primary divisions of the upper three cervical nerves. (Testut.) 



The posterior division of the third cervical nerve (Fig. 753) is intermediate 

 in size between those of the second and fourth. Its internal or cutaneous branch 

 passes between the Complexus and Semispinalis, and, piercing the Splenius 

 and Trapezius, supplies the skin over the latter muscle; while under the Trapezius 

 it gives off a branch called the third occipital nerve (n. occipitalis tertius), which 

 pierces the Trapezius and supplies the skin on the lower and back part of the head. 

 It lies to the inner side of the occipitalis major, with which it is connected. The 

 external branch often joins that of the second cervical. 



The posterior division of the suboccipital nerve and the internal branches of 

 the posterior divisions of the second and third cervical nerves are occasionally 



