400 
ANATOMY OF THE HOUSE. 
with the buccal nerve, artery, and varicose vein; antero-infeiiorly, 
with the depressor labii inferioris and inferior labial bloodves¬ 
sels ; postero-superiorly, with the temporal vein. 
Direction .—Longitudinal, from behind forwards. 
Structure. —With the exception of its posterior or narrow ex¬ 
tremity, which contains some slips of tendon, and a few tendi¬ 
nous fibres which are visible about the angle of the mouth, it is 
entirely fleshy. 
Use. —To aid in tightening the buccal membrane, and retract 
the angle of the mouth. 
depressor LABII iKTEmoRis.—MaxiUo-labialis. 
Situation. —Along the side of the lower jaw. 
Figure. —Elongated, flattened, pyramidal, base turned back¬ 
wards. 
Attachments. —Posteriorly, blended with 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, panniculus and skin, crossed also by 
the facial artery and vein and parotid duct; internally, inferior 
maxilla and buccinator; also 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 with the lip, in the glandular substance of 
which it expands, splits, and disperses its fibres. 
LEVATOR MENTI. — Me?ltO-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. 
Use. —To draw forward and raise the prominence of the chin, 
and with it the under lip. 
