DISSECTION OF THE HEAD AND NECK 279 



(ag) Supraorbital artery (A. supraorbitalis) . 

 (ah) Posterior ethnioidal artery (A. ethmoidalis posterior), 

 (ai) Anterior ethmoidal artery (A. ethmoidalis anterior), 

 (aj) Medial palpebral arteries (Aa. palpebrales mediates). Note 

 especially 



(aja) Superior tarsal arch (arcus tarseus superior). 



(ajb) Inferior tarsal arch (arcus tarseus inferior). 



(ajc) Posterior conjunctival arteries (Aa. conjuncti- t 



vales posterior es] . 

 (ak) Dorsal artery of nose (A. dorsalis nasi) (0. T. nasal 



branch). 

 (al) Frontal artery (A. frontalis). 



Veins. (Tributaries of the sinus cavernosus.) 



(a) Superior ophthalmic vein (V. ophthalmica superior). 



(aa) Naso frontal vein (V. naso frontalis) . 



(ab) Anterior and posterior ethmoidal veins (Vv. ethmoidales 



anterior et posterior). 



(ac) Lacrimal vein (V. lacrimalis). 



(ad) Muscular veins (Vv. muscular es). 



(b) Inferior ophthalmic vein (V. ophthalmica inferior). 



(c) Central vein of retina (V. centralis retinae). 



The following veins of the bulbus oculi and of the eyelids are 

 drained partly by the V. ophthalmica superior, partly by the V. 

 ophthalmica inferior: 



(d) Vortex veins (Vv. vorticosae). 



(e) Posterior ciliary veins (Vv. ciliares posteriores) . 



(f) Anterior ciliary veins (Vv. ciliares anteriores). 



(g) Episcleral veins (Vv. episclerales) . 

 (h) Palpebral veins (Vv. palpebrales). 



(i) Anterior and posterior conjunctival veins (Vv. conjunctivales pos- 

 teriores et anteriores). 



Other Straight Muscles of Eyeball. 



The M. rectus superior has already been studied and re- 

 flected. Examine the origin, insertion, position, action, and 

 innervation of each of the following muscles : 



(a) Medial straight muscle (M. rectus medialis) (0. T. rectus internus). 



(b) Inferior straight muscle (M. rectus inferior). 



(c) Lateral straight muscle (M. rectus lateralis) (0. T. external rectus). 



(ca) Lacertus of lateral straight muscle (lacertus musculi recti 

 lateralis). 



Divide the N. opticus close to the foramen opticum and turn 

 the eyeball forward. Examine the attachment of the eye-muscles 

 behind. What is meant by the common tendinous ring of Zinn 

 (annulus tendineus communis [Zinni]) (O. T. ligament of 

 Zinn)? 



