546 



THE BLOOD-VASCULAR SYSTEM 



and internal pterygoid muscles, sinks deeply into the pterygo-palatine (spheno- 

 maxillary) fossa, and there breaks up into its terminal branches. It is divided into 

 three portions: a mandibular, a pterygoid, and a pterygo-palatine. 



(1) In the first part of its course (the mandibular portion) the artery lies 

 between the neck of the mandible and the spheno-mandibular ligament, taking a 

 horizontal course forward, nearly parallel to and a little below the auriculo- 

 temporal nerve and the external pterygoid muscle. It is here embedded in the 

 parotid gland, and usually crosses in front of the inferior alveolar (dental) nerve. 



(2) In the second part of its course (the pterygoid portion) the artery may be 

 placed superficial or deep to the external pterygoid muscle. In the first case it 

 passes between the two pterj-goid muscles and the ramus of the jaw, and then 

 turns upward over the lateral surface of the external pterygoid, medial to the tem- 

 poral muscle to gain the two heads of the external pterygoid, between which it 



Fig. 451. — Scheme of Left Internal Maxillary. (Walsham.) 



Infraorbital artery and nerve 



Spheno-palatine branch 



ending palatine branch 



30-palatine branch 



Artery of the pterygoid canal (Vidian) 



Anterior deep temporal artery 

 External pterygoid branch 



Orbital branch 



Nasal branch 

 Anterior alveolarT^ 

 branch 



Labial branch 

 Posterior alve- 

 olar branch 



Alveolar branch 



Incisive branch 

 Mental branch 



Submental branch 



Buccal branch with 

 portion of buccal nerve 



Posterior deep temporal artery 

 Small meningeal 

 artery 



Middle meningeal 

 / / artery 



>ra Temporal artery 



— " — Anterior tympanic 

 Deep auricular 



branch 

 Auriculo-temporal 



nerve 

 Masseteric branch 



External carotid 

 artery 



Spheno-mandibu- 

 lar ligament 



.Inferior alveolar 

 artery and nerve 



Internal pterygoid branch 



Mylo-hyoidean branch 



sinks into the pterygo-palatine fossa. In the second case it passes medial to the 

 external pterygoid, and is covered by that muscle till it reaches the interval be- 

 tween its two heads, where it then often forms a projecting loop as it turns into the 

 pterygo-palatine fossa. 



(3) In the third part of its course (the pterygo-palatine portion) the artery 

 lies in the pterygo-pahxtine fossa beneath the maxillary division of the fifth nerve 

 and in close relationship with the spheno-palatine (Meckel's) ganglion, and there 

 breaks up into its terminal branches. 



Branches of the Internal Maxillary Artery 



The branches of the internal maxillary artery are: — 



(A) From the first part : — (1) The deep auricular; (2) the anterior tympanic; 

 (3) the middle meningeal; (4) the inferior alveolar (dental); (5) the accessory 

 meningeal (sometimes). All these vessels pass through bony or cartilaginous 

 canals. 



