THE ORBIT 



261 



also constitute bonds of union between the fascia bulbi and 

 the orbital wall. They are strong bands which pass from 

 the sheaths around the lateral and medial recti muscles 

 to obtain attachment to the zygomatic and lacrimal bones 

 respectively, where they are brought into association with 

 the extremities of the suspensory ligament. The function 

 of the check ligaments is to limit the contraction of the 

 medial and lateral recti muscles, and thus prevent excessive 

 rotation of the eyeball in a lateral or medial direction. 

 There is a similar but less direct" provision by means of which 

 the actions of the superior and inferior recti muscles are limited. 



Tendon of superior oblique 

 Tendon of superior rectus 



Tendon of lateral rectus 



Cut edge of fascia bulbi 

 and conjunctiva 



Tendon of inferior rectus 



Fascia bulbi thrown 

 back from eyeball 



Tendon of medial rectu 



FIG. 08. Dissection of the Fascia Bulbi from the front. 



The action of the superior rectus is checked through an 

 intimate connection with the levator palpebrae superioris in 

 the anterior part of the orbit ; the action of the inferior rectus 

 is checked through a connection with the suspensory ligament. 



Dissection. In order that the zygomatic branch of the 

 maxillary division of the trigeminal nerve may be displayed in 

 its course through the orbit, the orbital contents must be removed. 

 The nerve will then be found in the midst of a little soft fat in 

 the angle between the floor and lateral wall of the orbit. 



Nervus Zygomaticus (O.T. Temporo-Malar). The zygo- 

 matic nerve is small. It arises, in the infra-temporal fossa, 

 from the maxillary division of the trigeminal nerve. It enters 

 the orbit through the inferior orbital fissure, and almost 



in 17 6 



