DISSECTION OF THE HEAD AND NECK 235 



Find the posterior ramus of the suboccipital nerve (ramus 

 posterior N. suboccipitalis), the branches of which supply all 

 four. Establish the origin, insertion, and action of each muscle. 



What are the boundaries of the " suboccipital space, or 

 triangle' 7 ? (Fig. 97.) Note in the space 



(a) Posterior ramus of the first cervical nerve (N. sub occipitalis}. 



(b) Portion of the vertebral artery (A. vertebralis). 



Examine the floor of the space and distinguish 



(a) Posterior arch of the atlas (arcus posterior atlantis). 



(b) Posterior atlanto-occipital membrane (membrana atlanto-occipitalis 



posterior). 



Blood-vessels and Nerves of Neck and Back. 



The more superficial vessels of the neck have already been 

 studied. The student should carefully work out the following : 



Arteries. (Fig. 97.) 



(a) Occipital artery (A. occipitalis). How is it related to neighboring 



structures ? 



(aa) Muscular rami (rami musculares). 



To what muscles are these distributed? Note espe- 

 cially the descending ramus (ramus descendens) (0. T. 

 arteria princeps cervicis). 



(ab) Mastoid branch (ramus mastoideus). 



Into what foramen does this enter? 



(ac) Auricular branch (ramus auricularis ) . 



(ad) Occipital branches (rami occipitales) . 



(b) Ascending cervical artery (A cervicalis ascendens). 



(ba) Muscular branches (rami musculares). 



(bb) Deep ramus (ramus profundus). 



(c) Deep cervical artery (A. cervicalis profunda). 



With what vessels does this artery anastomose ? 



(d) Posterior ramus of highest intercostal artery (ramus posterior A. 



intercostalis supremae). 



(e) Posterior rami of intercostal arteries (rami posteriores Aa. inter- 



costalium). 



(ea) Muscular branches (rami musculares). 



(eb) Medial cutaneous rami (rami cutanei mediales). 



(ec) Lateral cutaneous rami (rami cutanei laterales). 

 Veins. 



(a) Occipital vein (V. occipitalis). 



(aa) Mastoid emissary vein (emissarium mastoideum). 



Why are the emissary veins of special importance? 

 Why is it a common practice to apply leeches and blisters 

 behind the ear in certain intracranial affections? 



(b) Deep cervical vein (V. cervicalis profunda}. 



(c) Posterior rami of intercostal veins (rami posteriores Vv. intercos- 



talium). 



