220 THE MUSCLES. 



4. Lachrymo-lahialj or Lachrymal Muscle. 

 (Synonym. Not mentioned by Percivall. It is the inferior palpebral muscle of Leyh.) 



A wide and very thin muscle, situated superficially below the eye : it is 

 continuous, in front, with the supernaso-labialis; behind, with the cu- 

 ticularis; above, with the orbicularis of the eyelids. Its fibres, partly 

 muscular and partly aponeurotic, leave the external surface of the lachrymal 

 and zygomatic bones, are directed downwards, and become lost in a cellular 

 fascia which covers the alveolo-labialis ; some pass beneath the zygomatico- 

 labialis and form the zygomaticus minor, when this is present. 



This muscle is supposed to corrugate and twitch the skin below the 

 eye. 



5. Supernaso-labialis. (Fig. 110, 15.) 



Synonyms. The maxillaris of Bourgelat. The levator labii superioris alseque nasi of 

 Man. (Levator labii superioris alseque nasi Percivall. Fronto-labialis Leyh.) 



Situation Direction Form Structure. Situated on the side of the 

 face, in an oblique direction downwards and backwards, 1 the supernaso- 

 labialis is a wide muscle, flattened on both sides, elongated from below to 

 above, aponeurotic at its superior extremity, and divided inferiorly into two 

 unequal branches, between which passes the great supermaxillo-nasalis. 



Attachments. It has its origin, by its superior aponeurosis, from the 

 frontal and nasal bones, and unites on the median line with the muscle of 

 the opposite side. Its anterior branch, the widest and thickest, goes to the 

 external ala of the nose and to the upper lip, where its fibres are confounded 

 with those of the orbicularis. The posterior branch terminates at the 

 commissure of the lips. 



Relations. Outwards, with the skin; inwards, with the supermaxillo- 

 labialis, the posterior portion of the small supermaxillo-nasalis, and vessels 

 and nerves. Its posterior branch covers the great supermaxillo-nasalis, 

 and the anterior is covered by that muscle. 



Actions. It elevates the external ala of the nose, the upper lip, and the 

 commissure of the lips. 



6. Supermaxillo-labialis. (Fig. 110, 16.) 



Synonyms. Levator labii sugerioris of Bourgelat. The levator labii superioris proprii of 

 Man. (Nasalis longus labii superioris Percivall.) 



Situation Direction Form Structure. Lying vertically on the side 

 of the face, below the supernaso-labialis, this muscle is a thick and conical 

 fleshy mass, terminated inferiorly by a tendon. 



Attachments. It is attached, by the upper extremity of its fleshy body, 

 to the external surface of the supermaxillary and zygomatic bones origin. 

 Its terminal tendon passes over the transverse muscle of the nose, to unite 

 with that of the opposite side, and with it to form a single aponeurotic 

 expansion, which dips by small fibres into the subcutaneous musculo-fibrous 

 tissue of the upper lip. 



Eelations. Covered by the lachrymal and supernaso-labialis muscles, 

 this muscle in turn covers the supermaxillary bone, the bottom of the false 

 nostril, the small supermaxillo-nasalis, and the transversalis nasi. 



Actions. It raises the upper lip, either directly or to one side, as it acts 

 singly or in concert with its congener. 



1 It is to be remembered that we suppose the head maintained in a vertical position. 



