90 AJUSCULAR SYSTEM. 



Altadiments. — Posteriorly, to the fore end of the zygoma, and 

 to the superior umxilla for a short space in front of it ; anteriorly, 

 it spreads upon the side of the nostril and the supero-lateral parts 

 of the upper lip. 



Relations. — Externally, with the skin and the inferior division 

 of the preceding muscle ; internally, with the superior division of 

 the same muscle, the caninus, the superior maxillary bone, and 

 the superior labial bloodvessels and nerves. 



Direcfiun. — Horizontal, diverging as it proceeds forwards. 



Sti'uctine. — A slender tendon attaches it to the bone, below 

 which it is fleshy. 



Action. — To dilate the nostril and retract the upper lip. 



NASALis LONGUS LABii suPERiORis. — Super-mnxillo-lahialis. 



Situation. — Upon the upper part of the side of the face. 



Figure. — Elongated, pyramidal, base turned backwards : ex- 

 ternal surface, convex; internal, flat. 



Attachments. — Posteriorly, to a slight bony depression at the 

 junction of the superior maxillary and malar bones, a short dis- 

 tance from the lower margin of the orbit; anteriorly, along the 

 middle of the anterior part of the upper lip. 



jRe/aif?o;/s. — Externally, with the skin and the levator labii su- 

 perioris alasque nasi, and the angular vein ; internally, with the 

 superior maxilla, pes anserinus, and false nostrils : the united 

 tendon crosses, in front, the dilatator naris anterior, and at the 

 border of the lip enters the substance of the labial gland. 



Direction' — Horizontal, the fleshy flbres gradually converging 

 from their origin to their termination in the tendon. 



Structure. — It has a few tendinous fibres at its origin ; other- 

 wise, it is fleshy as far forward as the false nostrils, where it ends 

 in a cylindroid tendon, and which here passes through a sort of 

 cellular sheath, by which it is retained in its proper place. In 

 turning over the front of the nose it grows flat, and at the peak 

 formed by the apices of the nasal bones forms a junction with its 

 fellow coming, from the opposite side. The two unite and form a 

 single flat tendon, which expands a little in descending, and ulti- 

 mately disa])pears in the fleshy substance of the lip. 



Action, — To raise and corrugate the upper lip, and in some de- 

 gree assist in the dilatation of the false nostrils. 



CANINUS VHL LEVATOR ANGULl ORIS. 



Portion of the aheolo-maxillaris. 



Situation. — Fore part of the side of the face. 

 Figure. — Broad, flat, triangular. 



