158 Anatomy of the; Rabbit. 



inferior labial artery fa. 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 branch of 

 the superficial temporal (p. 162). 



(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. These 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. 



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

 matic 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. 



(e) The buccinator is a broad stout band of fibres enclosing the 

 cheek and attached to the alveolar borders of the upper jaw 

 and mandible. 



(f) The caninus. Origin: Lateral border of the upper jaw. 

 Insertion: Hairy portion of the mucous membrane of the 

 mouth. The muscle is very broad, but short and extremely 

 thin. 



(g) The quadratus labii inferioris. Origin: Ventral border of 

 the mandible. Insertion: Skin of the lower lip. 



(h) The mentalis. The muscle surrounds the anterior portion of 



the mandible behind the incisor teeth. It is attached 



externally to the skin of the lower lip through the insertion 



portion of the quadratus labii inferioris, which largelv overlies 



it. 



3. Dissection on the ventral surface of the neck to free the external 



jugular vein and its tributaries. The cervical fascia and a portion of the 



parotid gland must be removed. 



The external jugular vein (v. jugularis externa) is formed behind the 

 angle of the mandible by the union of the anterior and posterior facial 

 veins. It passes backward in a superficial position to the superior 

 thoracic aperture. Its connections in the lower part of the neck comprise 



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

 be subdivisions of this muscle. 



