DISSECTION OF THE DOG 



185 



Glandula laceimalis. — The lachrymal gland will be found under the 

 orbital band and over the dorsal and lateral part of the eyeball. Flat in form 

 and curved conformably to the structures with which it is in contact, the gland 

 is pale-red in colour and distinctly lobulated. Generally its numerous ducts, 

 which open into the superior fornix, are too small to be satisfactorily dissected. 



Previously the two ends of the lachrymal and zygomatic nerves have been 

 examined. The middle part of their course is now revealed. These two 

 nerves — branches of the maxillary nerve — lie immediately under the periorbita, 

 and run together, or a very short distance apart, on the surface of the lateral 



m. obliquus inferior 



*n. frontalis 



n. lacrimalis 

 m. rectus superior 

 it. zygomaticus 

 m. rectus lateralis 



N m. rectus inferior 



1 m. plerygoideus 



it. spheno-pa'alinus 



■nn. infra-orbitales 

 Fig. 60. — Dissection of the orbit. 



straight muscle of the eyeball, towards the entrance to the orbit. The lachrymal 

 nerve is the more lateral and gives branches to the lachrymal gland. The 

 zygomatic nerve pierces the orbital band in order to reach the lower eyelid. 



N. ophthalmicus.— The ophthalmic nerve — the most dorsal division of 

 the fifth cerebral nerve — enters the orbit at its apex, and should be looked for 

 between the origins of the superior and lateral straight muscles of the eyeball. 

 It divides into the frontal, infratrochlear, and naso-ciliary nerves. Of these the 

 first named can be examined at once, but the dissection of the others should be 

 deferred for a little. 



N. frontalis. — The frontal nerve lies just within the periorbita, and will 

 be found running obliquely across the levator of the upper eyelid and the 

 superior straight muscle of the eyeball to the point of attachment of the orbital 



