DISSECTION OF THE HEAD AND NECK. 191 



ceding nerve. It is the direct continuation of the buccal vein already 

 dissected in the cheek. It will subsequently be followed to its termina- 

 tion, where it forms the jugular by union with the superficial temporal 

 vein. 



The Lingual Vein (Plate 30) drains blood away from the tongue. 

 It runs in company with the gustatory nerve ; and, after receiving- 

 branches from the soft palate and the pharynx, it joins the buccal vein 

 between the internal pterygoid muscle and the bone. 



Pterygoid Vessels. The pterygoid muscles derive their blood from 

 branches of the internal maxillary or of the inferior dental artery. 

 The inner muscle receives also the inner division of the maxillo- 

 museular artery. The pterygoid veins join the internal maxillary vein. 



Directions. — The external and internal pterygoid muscles must now 

 be removed. In cutting away the outer muscle the thick buccal nerve 

 will be found passing through it near its origin, and giving branches to 

 the muscle. The nerve is to be preserved to show its origin. Care 

 must also be taken of the internal maxillary vessels, and of the inferior 

 maxillary nerves, which are included between the muscle and the 

 guttural pouch. The internal pterygoid is to be cut close to its' origin, 

 and taken away without severing the vessels and nerves just dissected. 

 The pterygoid branch of the inferior maxillary division of the 5th nerve 

 will be found entering it, and an inch or two of the nerve should be 

 preserved to show its origin. Extending along the deep aspect of the 

 origin of the muscle is the tensor palati muscle, and care must be taken 

 not to injure it. The deep face of the internal pterygoid is related to 

 the pharynx, the guttural pouch, the great cornu of the hyoid bone, the 

 intermediate tendon of the digastricus, the larynx, and the submaxillary 

 gland. Besides these, it is related to Stenson's duct and the submaxillary 

 vessels, which have already been dissected on its surface in the inter- 

 maxillary space. 



The Guttural Pouches (Plates 31 and 32). There are two large 

 cavities situated at the base of the skull, above the pharynx, and be- 

 tween the great (styloid) cornua of the hyoid bone. Anteriorly they 

 extend as far as the upper margin of the posterior nares, and posteriorly 

 as far as the atlanto-axial articulation. Inwardly the mucous lining of 

 the two pouches forms a mesial partition. Outwardly each pouch has 

 numerous relations, the chief of which are as follows : Behind the 

 great cornu the pouch is covered by the submaxilliary gland, and the 

 stylo maxillaris, digastricus (upper belly), stylo-hyoid, and occipito- 

 styloid muscles, and is crossed by the external carotid, internal carotid, 

 and occipital arteries, and by the' 9th, 10th, 11th, 12th, and sympa- 

 thetic nerves. In front of the great cornu the pouch is covered by the 

 parotid gland and the internal pterygoid muscle, and is crossed by the 

 internal maxillary vessels, the chorda tympani nerve, and the inferior 



