INTERNAL MAXILLARY ARTERY. 431 



INTERNAL MAXILLARY ARTERY. 



(Fig. 163. B.) 



The continuation of the external CEirotid is the internal maxil- 

 lary artery, which commences at the inner side of the temporo- 

 maxillary articulation, just below the condyle, passes between the 

 neck of the lower jaw and the cornu of the os hyoides, where it 

 describes two successive curves, the first convex backwards, the 

 second convex forwards. It passes through the pterygoid fora- 

 men in the sphenoid bone, and gains the orbital hiatus ; crossing 

 the floor of the orbit, it enters the maxillary hiatus, and palatine 

 conduit, where it takes the name of the palatine artery. The 

 internal maxillary gives off the following branches before entering 

 the pterygoid foramen : — 



Inferior dental. 

 Pterygoid fasciculus. 



Tympanic. 

 Spheno-spinal. 



Posterior -deep temporal. 



The first two of these pass downwards, the rest upwards. 



The Inferior dental artery, given off from the middle of the 

 first curve of the internal maxillary, passes downwards and for- 

 wards between the internal and external pterygoids, enters the 

 dental foramen on the inner surface of the ramus of the lower 

 jaw, accompanied by the dental branch of the inferior maxillary 

 division of the fifth nerve, passes forward in the bone, supplying 

 the molars, and dividing at the neck of the jaw into two branches, 

 one supplying the tnsh and incisors, the other making its exit 

 through the mental foramen, to anastomose with the inferior 

 coronary artery, and terminate in the gums and lower lip. 



The Pterygoidean fasciculxts is a bundle of small arteries 

 which arises from the second curve, and is distributed chiefly to 

 pterygoid, the tensor and levator palati muscles. 



The Tympanic artery is a very small branch which passes into 

 the petrosal bone at the base of the Eustachian tube, and gains 

 the walls of the tympanum. 



The Spheno-spinal or Great meningeal artery enters the 

 cranial cavity by the foramen lacerum basis cranii, passing under 

 the dura mater, to which it supplies numerous branches ; it gains 

 the parieto-temporal conduit, inosculating with the mastoid branch 

 of the occipital artery. 



The Posterior deep temporal artery arises just as the main 



