PTERYGO-MAXILLARY REGION. 



329 



the curved line on the frontal and parietal bones above, to the pterygoid ridge 

 on the great wing of the sphenoid below. It is also attached to the inner sur- 

 face of the temporal fascia. Its fibres converge as they descend, and terminate 

 in an apooeurosis, the fibres of which, radiated at its commencement, converge 

 into a thick and flat tendon, which is inserted into the inner surface, apex, and 

 anterior border of the coronoid process of the jaw, nearly as far forwards as the 

 last molar tooth. 



Relations. . By its superficial surface, with the integument, the temporal fascia, 

 the aponeurosis of the Occipito-frontalis, the Attollens Aurem and Attrahens 

 Aurem muscles, the temporal vessels and nerves, the zygoma and Masseter. 

 By its deep surface, with the temporal fossa, the External Pterygoid and part 

 of the Buccinator muscles, the internal maxillary artery, its deep temporal 

 branches, and the temporal nerves. 



Nerves. Both muscles are supplied by the inferior maxillary nerve. 



10. PTERYGO-MAXILLARY REGION. (Fig. 219.) 



Internal Pterygoid. External Pterygoid. 



Dissection. The Temporal muscle having been examined, saw through the base of the coro- 

 noid process, and draw it upwards, together with the Temporal muscle, which should be detached 

 from the surface of the temporal fossa. Divide the ramus of the jaw just below the condyle, 

 and also, by a transverse incision extending across the commencement of its lower third, just 

 above the dental foramen; remove the fragment, and the Pterygoid muscles will be exposed. 



Fig. 219. The Pterygoid Muscles ; the Zygomatic Arch and a portion of the 

 Ramus of the Jaw having been removed. 



The Internal Pterygoid is a thick quadrilateral muscle, and resembles the 

 Masseter, in form, structure, and the direction of its fibres. It arises from the 

 pterygoid fossa, being attached to the inner surface of the external pterygoid 

 plate, and to the grooved surface of the tuberosity of the palate bone; its fibres 

 pass downwards, outwards, and backwards, to be inserted, by strong tendinous 

 laminae, into the lower and back part of the inner side of the ramus and angle 

 of the lower jaw, as high as the dental foramen. 



Relations. By its external surface, with the ramus of the lower jaw, from 

 which it is separated, at its upper part, by the External Pterygoid, the internal 

 lateral ligament, the internal maxillary artery, and the dental vessels and nerves. 



