ANATOMY IX A NUTSHELL. 529 



Internal pterygoid of the pterygo-maxillary region, the Superior constrictor of 

 the pharynx, the Tensor palati of the soft palate the Levator palpebral of the 



orbital region, the Superior oblique of the orbital region, the Superior rectus. 

 Inferior rectus. External rectus, and Internal rectus of the orbital region, and 

 the Laxator tympani. 



Blood Supply. — Middle and small meningeal, anterior deep temporal, 

 vidian, pterygopalatine and spheno-palatine, and twigs from the interna] 

 carotid. 



LESSON CLXXVIII. 



1. Temporal muscle which has been described on page 508. 



2. External pterygoid. — Description. — This muscle, which passes almost 

 horizontally between the zygomatic fossa and the condyle of the jaw. is a thick, 

 short muscle, conical in form. 



Origin. — It arises by two heads between which pass the buccal nerve and 

 the internal maxillary artery. The upper head comes from the pterygoid arch 

 and the inferior surface of the greater wing of the sphenoid, while the lower 

 head comes from the outer surface of the external pterygoid plate, and from 

 the tuberosities of the palate and superior maxillary bone. 



Insertion. — Into a depression in front of the condyle of the lower jaw. 

 and the inter-articular fibro-cartilage. 



Action. — To draw the condyle and interarticular fibro-cartilage forward 

 and inward. 



Nerve Supply. — Pterygoid branch of the inferior maxillary division of 

 the fifth. 



Blood Supply. — External pterygoid branches of the internal maxillary 

 artery. 



3. Internal pterygoid. — Description. — This muscle is a thick and quad- 

 rilateral. 



Origin. — From the inner surface of the external pterygoid plate and from 

 the tuberosity of the palate bone, and the adjacent pari of the superior maxil- 

 lary. 



Insertion. — Into the internal surface of the ramus of the jaw as high as 

 the mandibular foramen and mylo-hyoid groove. 



Action.— To close the mouth and to draw the lower jaw forward and 

 inward. 



Nerve Supply. — Inferior maxillary division of the fifth nerve. 



Blood Supply. Branches from the second division of the internal maxil- 

 lary artery. 



4. Superior constrictor muscle which has been described on pa^ 



5. Tensor palati muscle which ha- been described on page 



6. Levator palpebrae (superioris). Description. This muscle is tri- 

 angular in shape and is narrow ami tendinous at ii- origin, bu1 broad and 

 Meshy in its center and ends in a wide aponeurosis which passes between the 

 fibers of the Orbicularis to it > insertion. 



Origin. — From the under surface of the lesser wing of the sphenoid bone 

 above and in front of the optic foramen. 



