.lAlUSCULAR SYSTEM. 89 



T)ireclion. — Radiated : the fibres diverging from tlie optic 

 roramen as a centre, and spreading upon the surface of the globe. 



Stntcliire. — Posterior attachment, tendinous and fleshy : re- 

 mainder, fleshy. 



4.— ANTERIOR MAXILLARY REGION, 

 z Y G o M A T I c u s . — Zi/gomatico-lahia lis. 



Situation. — Along the middle of the side of the face. 



Figure. — Very thin, flattened, elongated. 



Attachment. — Posteriorly, to the anterior part of the zygoma, 

 and cellular tissue clothing the masseter; anteriorly, its fibres 

 grow faint and vanish imperceptibly in approaching the angle of 

 the mouth. 



Relations. — Externally, with the skin ; internally, with the 

 caninus ; inferiorly, with the panniculus carnosus. 



Direction. — Horizontal, from behind forwards. 



Structure. — Fleshy, except at its posterior attachment. 



Action. — To assist in retracting the angle of the mouth. 



LEVATOR LABII SUPERIORIS AL^QUE NASI. 



Super-naso-labialis. 



Situation. — Upon the side of the face, above the preceding- 

 muscle. 



Figure. — Broad, thin, elongated, bifurcated anteriorly. 



Attachments. — Posteriorly, to the subcutaneous surfaces of the 

 nasal and frontal bones, reaching as far backward as the level be- 

 tween the orbital arches; anteriorly, by one division to the lateral 

 parts of the skin of the nose and the false nostrils ; by the other 

 division, to the side of the upper lip and angle of the mouth. 



Relations. — Externally, with the skin ; the superior division, 

 with the dilatator naris lateralis : internally, with the nasalis lon- 

 gus labii superioris, pes anserinus, and the superior labial artery. 



Direction. — Rather oblique, from behind forwards, incliniiig 

 downwards. 



Structure. — Posteriorly, a broad and extended aponeurosis ; 

 anteriorly, fleshy. 



Action. — To assist in the retraction of the upper lip and angle of 

 the mouth, and in the dilatation of both the true and false nostrils. 



jRe/?io>'A\— Stubbs describes the aponeurotic expansion of this 

 muscle under the name of " epicranius." 



DILATATOR NARIS LATERALIS. — Super-maxUlo-nasalis magnus. 



Situation. — Upon the side of the face. 



Figure. — Flat, pyramidal, base presented forwards. 



N 



