DISSECTION OF THE HEAD AND NECK. 



215 



gland. In structure it is of the racemose type, resembling the salivary- 

 glands, but being looser in texture. Its secretion is discharged by a 

 number of ducts which open on the ocular surface of the upper eyelid, 

 close to the temporal canthus. The gland is to be removed. 



The Levator Palpebile Superioris is described at page 179. 



The Membrana Nictitans and its connection with the adipose tissue 

 of the cavity are described at page 177. 



Muscles of the Eyeball. — These are seven in number, viz., four recti, 

 one retractor, and tw T o oblique. 



Fig. 25. 



Muscles of the Right Eyeball (viewed from above). 



1, 1. Superior oblique; 2. Fibrous loop for the same; 3. Superior rectus; 4. 

 5. External rectus ; (3. Inferior rectus ; 7, 7, 7. Fasciculi of the retractor ; S. 

 levator of the upper eyelid ; 9. Nerve to inferior oblicpie. 



Internal rectus ; 

 Cut origin of the 



Directions. — The muscles are to be denned by detaching the eyelids 

 and conjunctiva from the front of the eye, and removing the levator 

 palpebrse and the loose fat which forms a packing material, between the 

 muscles. Special care must be taken not to injure the fibrous arch for 

 the tendon of the superior oblique at the inner side of the orbit. 



The Recti. There are four of these, distinguished as the superior 

 rectus, the inferior rectus, the external rectus, and the internal rectus. 

 They are placed one above, one below, and one on either side of, 

 the eye. They have all a flat riband-like form, and are terminated 

 anteriorly by aponeurotic tendons. They all take origin around the 

 optic foramen, and each becomes inserted into the forepart of the 

 sclerotic. 



