382 SURGICAL ANATOMY. 



muscles, and the lachrymal gland. Other branches descend through canals i'u the 

 bone, to supply the mucous membrane of the antrum, and the front teeth of the 

 upper jaw. On the face, it supplies the lachrymal sac, and inner angle of the 

 orbit, anastomosing with the facial artery and nasal branch of the ophthalmic; 

 and other branches descend beneath the elevator of the upper lip, and anastomose 

 with the transverse facial and buccal branches. 



The four remaining branches arise from that portion of the internal maxillary 

 which is contained in the spheno-maxillary fossa. 



The descending palatine passes down along the posterior palatine canal with the 

 posterior palatine branches of Meckel's ganglion, and, emerging from the posterior 

 palatine foramen, runs forwards in a groove on the inner side of the alveolar 

 border of the hard palate, to be distributed to the gums, the mucous membrane 

 of the hard palate, and palatine glands. Whilst it is contained in the palatine 

 canal, it gives off branches, which descend in the accessory palatine canals to 

 supply the soft palate, anastomosing with the ascending palatine artery ; and ante- 

 riorly it terminates in a small vessel, which ascends in the anterior palatine canal, 

 and anastomoses with the artery of the septum, a branch of the spheno-palatine. 



The Vidian branch passes backwards along the Vidian canal with the Vidian 

 nerve. It is distributed to the upper part of the pharynx and Eustachian tube, 

 sending a small branch into the tympanum. 



The ptery go-palatine is also a very small branch, which passes backwards 

 through the pterygo-palatine canal with the pharyngeal nerve, and is distributed 

 to the upper part of the pharynx and Eustachian tube. 



The nasal or spheno-palatine passes through the spheno-palatine foramen into 

 the cavity of the nose, at the back part of the superior meatus, and divides into 

 two branches ; one internal, the artery of the septum, passes obliquely downwards 

 and forwards along the septum nasi, supplies the mucous membrane, and anasto- 

 moses in front with the ascending branch of the descending palatine. The 

 external branches, two or three in number, supply the mucous membrane cover- 

 ing the lateral wall of the nares, the antrum, and the ethmoid and sphenoid cells. 



SURGICAL ANATOMY OF THE TRIANGLES OF THE NECK. 



The student having considered the relative anatomy of the large arteries of the 

 neck and their branches, and the relations they bear to the veins and nerves, 

 should now examine these structures collectively, as they present themselves in 

 certain regions of the neck, in each of which important operations are being con- 

 stantly performed. 



For this purpose, the Sterno-mastoid, or any other muscles that have been 

 divided in the dissection of these vessels, should be replaced in their normal posi- 

 tion ; the head should be supported by placing a block at the back of the neck, 

 and the face turned to the side opposite to that which is being examined. 



The side of the neck presents a somewhat quadrilateral outline, limited, above 

 by the lower border of the body of the jaw, and an imaginary line extending 

 from the angle of the jaw to the mastoid process; below, by the prominent upper 

 border of the clavicle ; in front, by the median line of the neck ; behind, by the 

 anterior margin of the Trapezius muscle. This space is subdivided into two large 

 triangles by the Sterno-mastoid muscle, which passes obliquely across the neck, 

 from the sternum and clavicle, below, to the mastoid process, above. The trian- 

 gular space in front of this muscle is called the anterior triangle and that behind 

 it, the posterior triangle. 



ANTERIOR TRIANGULAR SPACE. 



The anterior triangle is limited, in front, by a line extending from the chin to 

 the sternum; behind, by the anterior margin of the Sterno-mastoid; its base, 

 directed upwards, is formed by the lower border of the body of the jaw, and a line 



