THE HEAD AND NECK 1063 



colli, with (i) the deep cervical of the superior intercostal of the 

 second part of the subclavian, and (2) branches of the vertebral 

 artery. The communicating branches enter the suboccipital 

 triangle, where they anastomose with branches of the vertebral 

 artery. The muscular branches supply the contiguous muscles. 

 The terminal branches are at first two in number, but these soon 

 divide into several long tortuous branches, which supply the 

 occipitalis and the integument as high as the vertex. They anas- 

 tomose with the posterior auricular, the posterior division of the 

 superficial temporal, and their fellows of the opposite side. 



The occipital venous plexus communicates with the posterior 

 auricular, and the posterior branch of the superficial temporal, veins. 

 It receives the parietal emissary vein, which emerges through the 

 parietal foramen, and so a' communication is established with the 

 superior longitudinal sinus. Sometimes it receives a small occipital 

 emissary vein, which emerges through an opening at the external 

 occipital protuberance, and then a communication would be 

 established with the torcular Herophili. 



Two or three occipital veins emerge from the occipital plexus. The 

 external vessel is known as the posterior jugular vein. It receives 

 the mastoid emissary vein, which emerges through the mastoid 

 foramen, and so an important communication is established with 

 the lateral sinus. Having been reinforced by tributaries from the 

 superficial structures at the upper part of the back of the neck, 

 the posterior jugular vein passes on to the stemo-cleido-mastoid, 

 where it opens into the external jugular. The middle occipital 

 vein (inconstant) accompanies the occipital artery, and usually 

 opens into the internal jugular. The internal occipital vein, having 

 in some cases pierced the trapezius, passes beneath the complexus, 

 and enters the suboccipital triangle. In this situation it joins the 

 suboccipital plexus, from which the deep cervical and vertebral 

 veins emerge. 



Occipital Glands. — ^These glands are usually two in number, and 

 lie over the occipital portion of the trapezius, or over the upper 

 part of the complexus. They receive their afferent lymphatics 

 from the back part of the scalp, and their efferent lymphatics pass 

 to the deep cervical glands. 



Deep Cervical Artery. — This vessel is a branch of the superior 

 intercostal of the second part of the subclavian. Having passed 

 backwards between the transverse process of the seventh cervical 

 vertebra and the neck of the first rib, it ascends upon the semi- 

 spinalis colli, under cover of the complexus, towards the level of 

 the spine of the axis, where it anastomoses with the deep branch 

 of the arteria princeps cervicis of the occipital. In its course it 

 furnishes a spinal branch, which enters the spinal canal through the 

 intervertebral foramen for the eighth cervical nerve, and muscular 

 branches, which anastomose with branches of the vertebral artery. 



The deep cervical vein commences, within the suboccipital triangle, 

 in the suboccipital plexus, which receives the internal occipital 



