58 ANATOMY AND PHYSIOLOGY FOR NURSES 



Nasal Region. In this region there are seven pairs of 

 muscles, which control the lip and act as levers to lift it; 

 - they also control the size of the anterior nares. These 

 are, to a certain degree, muscles of expression; each 

 muscle has its own function to perform, and each acts 

 antagonistically to the other that is, some dilate, while 

 others constrict, the parts concerned in their movements. 



FIG. 32. Muscles of the orbit: i, Levator palpebrae superioris; 2, ob- 

 liquus superior ; 3, pulley of obliquus superior ; 4, rectus superior; 5, rectus 

 inferior; 6, rectus externus ; 7, lower head of rectus externus; 8, upper 

 head of rectus externus; to, obliquus inferior; n, optic nerve (Leidy). 



Superior Maxillary Region. In this region there 

 are four muscles on each side; they are connected to the 

 superior maxillary and malar bones, and arise from the 

 lower margin of the orbit; some of them are inserted into 

 the muscular substance of the upper lip. They are named 

 as follows: Levator labii superioris, levator anguli oris, 

 zygomaticus major, zygomaticus minor. (See Fig. 31.) 



Action, elevate the upper lip; draw the mouth inward 

 and outward, as in laughing or displaying any emotion, 



