92 MUSCULAR SYSTEM. 



Attac/i/neiits. — Posteriorly, blended wi_th the buccinator, to the 

 tuberosity of the superior maxilla, and the superior border of the 

 inferior maxilla, behind its alveoli ; anteriorly, infero-lateral part 

 of the interior of the lower lip. 



Relations. — Externally, with the panniculus and skin, crossed 

 also by the facial artery and vein and parotid duct ; internally, 

 with the inferior maxilla and buccinator; also with the inferior 

 labial bloodvessels, which run between it and the buccinator. 



Direction. — Horizontal, the fibres very gradually converging. 



Structure. — Two slender tendons attach it to the jaws, and 

 another connects it Vv'ith the lip, in the glandular substance of 

 which the latter expands, splits, and disperses its fibres. 



LEVATOR M E N T i . — Meuto-labialis. 



Situation. — Under the chin. 



Figure. — Broad, and (though rather irregularly) quadrilateral. 



^Attachments. — Superiorly, to the alveolar processes, and the 

 antero-inferior and lateral parts of the inferior maxilla ; inferiorly, 

 its fibres are lost sight of amid the adipose and glandular sub- 

 stance forming the prominence of the chin. 



Relations. — Superiorly, with the bone ; inferiorly, with the 

 membrane lining the lip ; anteriorly, with the teeth ; posteriorly, 

 with the prominence of the chin. 



Direction. — Oblique, from before backwards, and from above 

 downwards ; the lateral fibres making a curvature forwards. 



Structure. — Fleshy. 



Action.— To draw forward and raise the prominence of the chin, 

 and with it the under lip. 



DILATATOR NARis ANTERIOR. — Naso-transversalis. 



Situation. — In front of and between the nostrils. 



Figure. — Transverse parallelogram . 



Attachments. — In the middle, to the bony peak formed by the 

 apices of the ossa nasi ; on the side, to the anterior surface of the 

 alas or broad cartilages of tlie nose. 



Relations. — Externally, with the skin and the united tendon 

 belonging to the nasales longi labii superioris ; internally, to the 

 broad and also to the narrow cartilages of tlie nose, and to the 

 triangular space between them ; superiorly, with the ossa nasi ; 

 inferiorly, with the glandular substance of the lip. 



Direction. — Transverse. 



Structure. — Fleshy, except at its attachment to the os nasi. 



