236 Anatomy of the Rabbit. 



its branches crossing the masseter. They are distributed as 

 motor nerves to the cutaneous muscles of the face, including 

 the platysma. 



(d) The external maxillary artery (a. maxillaris externa) ap- 

 pears at the ventral border of the mandible immediately in 

 front of the masseter. It passes upward to the anterior 

 margin of the eye, ending in the angular artery (a. angul- 

 aris). Its chief branches to the anterior portion of the face 

 are: (1) the submental artery (a. submentalis) to the chin; 

 (2) the inferior labial artery (a. labialis inferior) to the 

 lower lip; and (3) the superior labial artery to the 

 upper lip. 



A small vessel, the transverse facial artery, crosses the cheek, 

 running along the ventral border of the zygomatic arch. It is a branch 

 of the superficial temporal (p. 242). 



(e) The anterior facial vein (v. facialis anterior) accompanies 

 the external maxillary artery. It begins in front of the eye 

 as the angular vein, and receives as tributaries the superior 

 and inferior labial veins. 



2. Dissection of the facial muscles. Thc-e muscles arise from the 

 facial portion of the skull, and are inserted, into the skin about the 

 upper and lower lips. 



(a) The quadratus labii superioris. Origin: Dorsal portion 

 of the maxillary fossa. Insertion: Skin of the upper lip.* 



(b) The subcutaneus faciei. Origin: Lateral border of the 

 premaxilla, its frontal process, and the supraorbital process 

 of the frontal. Insertion: Skin of the dorsal surface of the 



nose. 



The muscle is closely associated in front of the eye with a conspicuous 

 band of fibres arising from the anterodorsal margin of the zygomatic 

 arch. The latter muscle is probably a corrugator supercilii, operating 

 in conjunction with the orbicularis in firmly closing the eye. 



(c) The zygomaticus minor. Origin: Anterior end of the 

 zygomatic arch. Insertion: Skin of the angle of the mouth. 



(d) The levator alae nasi. Origin: Maxillary fossa. Insertion: 

 Lateral cartilage of the nose. The muscle is very slender, 

 and is inserted by a long tendon which underlies the in- 

 sertion portion of the quadratus labii superioris. 



*The levator alae nasi, and zygomaticus minor muscles may be considered to 

 be subdivisions of this muscle. 



