Chap, iv.] THE ORBIT AND EYE. 37 



aware of it. A stranger case, in some ways, is that 

 reported by Furneaux Jordan : "A man, who was 

 employed in threshing, became the subject of severe 

 ophthalmia. At the expiration of several weeks, the 

 patient, whilst pressing his finger on the lower eyelid, 

 suddenly ejected from a comfortable bed of warm pus 

 a grain of wheat, which had shot forth a vigorous 

 green sprout." The orbital fat affords also an excel- 

 lent nidus for growing tumours. Fractures of the 

 inner wall of the orbit involving the nasal foss?e or 

 sinuses, may lead to extensive emphysema of the orbital 

 cellular tissue. The air so introduced may cause the 

 globe to protrude, may limit it's movements, may 

 spread to the lids, and will, in any case, be increased 

 in amount by blowing the nose, etc. 



The orbital arteries are small, and seldom give 

 rise to trouble when divided in excising the globe, 

 since they can be readily compressed against the bony 

 walls of the cavity. Pulsating tumours of this part 

 may be due to traumatic aneurisms of one of the 

 orbital arteries, or may depend upon an arterio-venous 

 aneurism formed between the internal carotid artery 

 and the cavernous sinus. Pressure also upon the 

 ophthalmic vein (as it enters the sinus), by an aneurism 

 of the internal carotid vessel, may produce all 

 the symptoms associated with pulsating orbital 

 tumours. 



The orbital nerves may be damaged in wounds 

 of the orbit, or in fractures of the orbit and of the 

 base of the skull. They may be pressed upon by 

 tumours from various parts, by aneurisms, hseniorr- 

 hagic and inflammatory effusions. Thus Lawson re- 

 cords a case in which the optic nerve was divided by a 

 stab through the upper eyelid, without the globe being 

 injured, and without any bone being fractured. The 

 same nerve has also been completely torn across in 

 fractures of the orbit, and has been pressed upon in 



