THE PHARYNX 405 



divisible into two parts. It presents for description two surfaces, two borders, and 

 two extremities. The lateral surface is covered by the parotid gland, the occipito- 

 mandibularis, digastricus, and pterygoideus medialis muscles. The tendon of the 

 sterno-cephalicus crosses this surface, and, together with the aponeurosis connect- 

 ing it with that of the brachiocephalicus, is a useful guide in separating the parotid 

 gland from it. The medial surface is related to the rectus capitis ventralis major, 

 the guttural pouch, the larynx, the division of the carotid artery, and the tenth, 

 eleventh, and sympathetic nerves. The dorsal border is concave and thin. It 

 is related to the guttural pouch and the duct of the gland. The ventral border 

 is convex and thicker. It is related to the external maxillary vein and often to 

 the thyroid gland. The posterior extremity is loosely attached in the fossa atlantis. 

 The anterior extremity lies at the side of the root of the tongue, and is crossed 

 laterally by the external maxillary artery. The mandibular or submaxillary duct 

 (Ductus mandibularis s. submaxillaris) "^ is formed by the union of small radicles 

 which emerge along the concave edge. It runs forward along this Ijorder, and, after 

 leaving the anterior extremity, crosses the intermediate tendon of the digastricus, 

 passes between the hyo-glossus and mylo-hyoideus, and gains the medial surface 

 of the sublingual gland. Its terminal part lies on the body of the mandible, under 

 the mucous membrane, which it pierces opposite the canine tooth. The orifice is 

 at the end of a flattened papilla, the caruncula sublingualis. The gland differs 

 in finer structure from the parotid in possessing serous, mucous, and mixed 

 alveoli. 



Blood-supply. — Occipital, external carotid, and external maxillary arteries. 



Nerve-supply. — Chorda tympani and sympathetic nerves. 



The sublingual gland (Glandula sublingualis) (Figs. 330, 561) is situated be- 

 neath the mucous membrane of the mouth, between the body of the tongue and the 

 ramus of the mandible. It extends from the symphysis to the third or fourth 

 lower cheek tooth. Its length is about five or six inches (ca. 12 to 15 cm.) and its 

 weight about half an ounce (ca. 15 to 16 g.). It is flattened laterally, and has a 

 thin dorsal border which underlies the sublingual fold of the mucous membrane 

 of the floor of the mouth. The lateral surface is related to the mylo-hyoideus 

 mmscle, and the medial surface to the genio-glossus and stylo-glossus, the mandib- 

 ular duct, and branches of the lingual nerve. The ventral border is related to 

 the geniohyoid muscle. The sublingual ducts (Ductus sublinguales), about thirty 

 in number, are small, short, and twisted; they open on small papillae on the sub- 

 lingual fold. The gland has mixed alveoli. 



Blood-supply. — Sublingual artery. 



Nerve-supply. — Trigeminal and sympathetic nerves. 



THE PHARYNX 

 The pharynx is a musculo-membranous sac which belongs to the digestive and 

 respiratory tracts in common. It is somewhat funnel-shaped, the large anterior 

 part joining the mouth and nasal cavity, while the small end is continued by the 

 oesophagus. Its long axis is directed obhquely downward and backward, and has 

 a length of about six inches (ca. 15 cm.). The pharynx is attached by its muscles 

 to the palatine, pterygoid, and hyoid bones, and to the cricoid and thyroid cartilages 



of the larynx. . , .i x. i 



Its principal relations are: dorsally, the base of the cranium and the guttural 



pouches; ventrally, the larynx; laterally, the medial pteryoid muscle, the great 



cornu of the hyoid bone, the external carotid and external maxillary arteries, the 



1 Formerly known as Wharton's duct. 



