542 



THE BLOOD-VASCULAR SYSTEM 



It lies to the medial side of the lacrimal sac and supphes that structure and the lower part of 

 the orbicularis oculi, beneath which a branch anastomoses with the mfraorbital artery. The 

 situation of the artery to the medial side of the lacrimal sac should be borne m mmd m openmg 

 a lacrimal abscess. 



Fig. 449. — Scheme of the Right External Maxillary Artery. (Walsham.) 



Orbicularis oculi muscle 



Transverse facial artery 

 Quad, labii sup., 

 zygomatic head 



Zygomaticus muscle 



Buccinator muscle 



Masseteric branch 



Masseter muscle 



Stylo-pharyngeus 

 muscle 

 Stylo-glossus muscle 

 Ascending palatine 

 branch 

 Tonsillar branch 



External maxillary ^, 

 artery J ' 



External carotid V-^ 

 artery \ ^ -(' 



Posterior belly of _|.^ 

 digastric muscle 



Lingual artery # 



) 



Frontal branch of ophthal- 

 mic artery 

 Dorsal nasal branch of ophthal- 

 mic artery 



Angular artery 

 Quad, labii sup., 



angular head 

 Infraorbital artery 

 Quad, labii sup., 

 infraorbital head 

 Lat. nasal artery 

 Caninus muscle 

 _ Artery of septum 

 Superior labial 

 artery 



Risorius muscle 



Inferior labial srtery 



Mental branch of inferior 



alveolar artery 

 Quadratus labii inferioris 



muscle 

 ■Inferior labial artery 

 .Triangularis muscle 



Submental artery 

 .^Branches to submaxillary 

 gland 

 Anterior belly of digastric muscle 



Mylo-hyoid muscle 



Hyo-glossus muscle 



Hypoglossal nerve 



5. THE STERNOCLEIDOMASTOID 



The sternocleidomastoid urtcrv [a. sternocleidomastoidea] arises from the 

 po.st(!rior si(l(; of the external carotid at tlie point where the carotid is crossed by 

 the digastric muscle. It is distributed to the sternocleidomastoid muscle, and is 

 frequently represented by onv, of tlu; muscuilar branches of the occipital artery. 



G. THE OCCIPITAL ARTERY 



The occipital artery [a. occipitalis] (fig. 450) is usually a vessel of considerable 

 size. It (!omes off from the posterior part of the external carotid opposite the 

 external maxillary (facial), or else a little higher than that vessel. It then winds 



