FACIAL REGION. 21 



attached to the anterior border of the septum. Below 

 these are the alar fibro-cartilages ; these are curved in 

 such a way as to form the rim of the nostril; anteriorly 

 they form the apex of the nose, and their inner portions 

 at this part turn backward along the septum nasi. This 

 cartilage has no osseous attachment, but is connected by 

 fibrous tissue with th'e lateral cartilages and the integu- 

 ment. To the outer curve of the alar cartilage are at- 

 tached several small cartilages connected with each other 

 by fibrous tissue ; these are called the sesamoid cartilages. 

 The septum nasi is triangular in form and divides the nose 

 into its two nostrils : it is attached above to the nasal 

 bones and lateral cartilages, posteriorly it unites with the 

 vomer, and below with the palate process of the superior 

 maxillary bones. 



The ORBICULARIS ORIS is an elliptical-shaped muscle 

 forming a sphincter round the mouth ; it has no osseous 

 attachment; its fibres cross each other at the angles of the 

 mouth ; those belonging to the upper lip join the lower 

 portion of the buccinator muscle, and those from the lower 

 lip join with the upper part of the same muscle. Beneath 

 this muscle lies the mucous membrane of the lips, and be- 

 tween this and the muscular fibres are the coronary branch 

 of the facial artery, and numerous small, rounded mucous 

 glands, called labial glands. 



The DEPRESSOR LABII INFERTORIS, or QUADRATUS MENTT, 

 arises from the oblique line of the inferior maxillary bone, 

 and, blending with its fellow of the opposite side, is in- 

 serted into the orbicularis oris at the central part of the 

 portion belonging to the lower lip. 



The DEPRESSOR ANGULI ORIS, or TRIANGULARIS MENTT, 

 arises more externally from the same oblique line of the 

 inferior maxillary bone, and is inserted into the orbicularis 

 oris near the angle of the lips ; its most external fibres will 

 be found continuous with some of those of the zygomaticus 

 major. 



Both of the last-described muscles are made up of fibres 

 from the platysma myoides of the neck ; and if they have 

 been carefully dissected, the continuity may be traced with 

 the greatest ease. 



Beneath the depressor anguli oris will be seen issuing 

 from the mental foramen, the termination of the inferior 

 dental branch of the inferior maxillary trunk of the fifth 

 pair of cranial nerves ; its filaments suppl} r the muscles and 



