Pig. 47. Frontal Section through Anterior Portion of Cavernous Sinus. 

 Fig. 48. Frontal Section through Posterior Part of Cavernous Sinus. 



Sections of the same series as those shewn in Fig. 4^ and 46. Section 4y pas- 

 sed o.j' incli beliind section 46, and 48 passed o.} inch behind 47. 



On either side of the Sella Turcica is the Cavernous Sinus the most 

 complicated of all the sinuses formed by the Dura Mater. It contains the Inter- 

 nal Carotid Artery, the 3rd, 4th and 6th Cranial Nerves, and is in close relation 

 with the I St division of the 5th Nerve. The Dura Mater is at some distance 

 from the bone, and thus forms with it a space which contains the structures 

 mentioned amid numerous veins. These veins are partly plexiform in character. 

 This sinus is, therefore, unlike the others, not a large venous channel, but a mass 

 of freely anostomosing veins. Both cavernous sinuses are joined to one another 

 by two transx'erse veins which pass respectivel}' in front of and behind the Pituitary 

 Bod}'. Thus a venous ring", the Circular Sinus (or Sinus of Ridley) is formed. 



Primary thrombosis of the Cavernous Sinus is rare; thrombosis usually 

 occurs secondar\- to the Lateral Sinus with which it communicates through the 

 Superior Petrosal Sinus, or by the spreading of a thrombus along the 

 Ophthalmic Vein. Empyaema of the Sphenoidal Sinus may also give rise to this 

 thrombosis, as the intervening bone is very thin; this process is absolutely 

 analagous with the thrombosis of the Lateral Sinus due to pus in the Mastoid 

 Process. The anatomical relations explain why thrombosis of the Cavernous 

 Sinus ma}' produce Neuralgia of the first division of 5th C. N., Paralysis of 3rd, 

 4th and 6th Nerves, and wh}' congestion or thrombosis of the Ophthalmic Vein 

 can be followed by Oedema of the Eyelids, Retro-bulbar Oedema and Ex- 

 ophthalmos. 



Surgical treatment for thrombosis of the Cavernous Sinus has hitherto 

 only once been attempted with success. The diseased sinus was reached by 

 removing the petrous portion of the temporal bone, attacking it from the ear. 

 It can also be got at by the channel made for the removal of the Gasserian 

 Ganghon. 



Should the Internal Carotid Arter}' be injured where it lies in the Caver- 

 nous Sinus, with a sharp instrument entering the Orbit, or by a piece of bone 

 (fracture), or through a shot, or should the vessel burst .spontaneously (calcified 

 arteries in old people), an abnormal communication may be formed between the 

 artery and the sinus (Aneurysm by Anastomosis), the consequence is a pulsating 

 Exophthalmos which is a rather curious condition. 



A glance at the figures shews that dangerous haemorrhage may follow 

 the tearing of the ist division of the 5th C. N. in the removal of the Gasserian 

 Ganglion. Externall}' to this nerve lies a venous space, which was unequally 

 developed on the two sides in our specimen. 



