30*2 MUSCLES OF THE EYELIDS. 



3. Retrahentes Auris, 



Arise, sometimes by three, but always by two distinct small 

 muscles, from the external and posterior part of the root of the 

 mastoid process, immediately above the insertion of the sterno- 

 cleido-mastoid muscle. 



Inserted into that part of the^back of the ear which is oppo- 

 site to the septum that divides the scapha and concha. 



Use. To draw the ear back, and stretch the concha. 



Muscles of the Eyelids. 



The palpebrae or eyelids, have one muscle common to both, 

 and the upper eyelid one proper to itself. 



1. Orbicularis Palpebrarum, 



Arises, by a number of fleshy fibres, from the outer edge of 

 the orbitar process of the superior maxillary bone, and from a 

 tendon near the inner angle of the eye ; these run a little down- 

 wards, then outwards, over the upper part of the cheek, below 

 the orbit covering the under eyelid, and surround the external 

 angle, being loosely connected only to the skin and fat ; run 

 over the superciliary ridge of the os frontis, towards the inner 

 canthus, where they intermix with those of the occipito-fron- 

 talis and corrugator supercilii ; then covering the upper eyelid, 

 they descend to the inner angle opposke to the inferior origin 

 of this muscle, firmly adhering to the internal angular process 

 of the os frontis, and to the short round tendon which serves to 

 fix the palpebrae and muscular fibres arising from it. 



Inserted, by the short round tendon, into the nasal prdcess 

 of the superior maxillary bone, covering the anterior and upper 

 part of the lachrymal sac ; which tendon can be easily felt at 

 the inner canthus of the eye. 



Use. To shut the eye, by drawing 'both lids close together, 

 the fibres contracting from the outer angle towards the inner, 

 press the eyeball, squeeze the lachrymal gland, and convey the 

 tears towards the puncta lachrymalia. 



When the muscle is in strong action, its upper fibres 



