Cavernous Sinus - Study Note

CAVERNOUS SINUSCAVERNOUS SINUSPaired sinuses, situated on each side of the bodyof spheroid bone.Each sinus extends from thesuperior orbital fissure in front to the apex of petrous temporalbehind. The interior of the sinus, when collapsed in dissected cardavers,is found to the tranversed by interlacement of reticular fibresmarking the sinus spongy in appearence. Hence it is called Cavernous.But the distended sinus in adult contains tabecular only at theperiphery of the sinus near the entry of its tributaries.MEASUREMENTSLength: Breadth: 1em.2em.FORMATIONand endosteal layers of dura matter.Each sinus is formed by the separation between menigealThe sinus is filled with venous bloodRoof and latral wall are formed by the meningeal layerand is covered with an endothelial lining.Floor and medial wall by the endostical layer.STRUCTURES PASSING THROUGH THE SINUSINTERNAL CAROTID ARTERYEnters through apex of perrous partPasses along the foor of the Sinus lodging in carotid sulcus ofthe body of sphenoidlater tums upward to pience the root of the sinus throughthe carotido clinoid faramen.ABDUCENT NERVEHuman Anatomy For ExamIt enters below the petro-sphenoid ligament andAccompanies infero-lateral to the internal Carotid artery.The nerve leaves through the superior orbital fissure withinSTRUCTURES WITHIN LATERAL UWALL OF THE SINUS (are as follows from abovethe common tendinous ring.drondwardsOcalomotor Nerve:- Enters by piercing the roof of the sinusLeaves the sinus through the tendinous ring by dividing into 2 rami.Tronchlear Newe: -Enters similar to oculomotor nerveLeares the sinus through the superior orbital fissure outside thetendinous ring. CAVERNOUS SINUS2Opthalmic Nerve :-Enters by piercing the Cavum trigeminate andlaural wall of sinus.Leaves through the superior arbital fissure by dividing intolacrimal, frontal and masociliary branches.Maxillary Nerre:- Enters - (Entry is similar to the opehalmic N 1)Leaves the sinus through the foramen rotur dum.NOTE to The above mentioned Structures are separated from theVenous blood by the endotherial lining of the sinus.CAVERNOUS SINUS: EXTERNAL RELATIONSMEDIALLY & BELOWDIPANDKAR RAY1Hypophysis Cerebri (2) Sphenoidal air sinus.LATERALLYCanum trigeminale containing the(2) Uncus of the Temporal lobetrigeminal ganglion in the postero-inferiorpart of the Nateral wall!ABOVEHuman Anatoms For Exam(1) A part of Optic chiasma. (2) Internal Carotid astery turns backwardand the upward (Carotid siphon)TRIBUTARIES1 Superior Opthalmic Vein(5) A few inferior Cerebral veins.2A Branch from inferior opthalmic(6) Sphero-parietal Sinus.vein(7) Sometimes anterior think (frontal)(3) Sometimes Central vein of Retinaof middle meningeal vein.(4) Superficial middle Cerebral Vein CAVERNOUS SINUS3COMMUNICATIONSHuman Anarymy FreExam.(A) Transverse Sinus (with) :- Via superior petrosal sinus(B) Internal Jugular Vein (with) :- Through inferior petrosal sinusand a plexus of veins aroundinternal carotid artery.(e) Pterygoid Venous Plexus (with) :- Through emissary veins whichpass through the forarven arale,foramen spinosum, foramen Vesali and Paramen laserum.DFacial vein (by 2 Rouces) (with):- (i) Superior opthatmic vein andangular vein.DIPAHMAR RAY(ii) Pteryouid verous plexus and deepfarcial Vein.(E) Opposite Cavemous Sinus (with): Via anterior and posteriorintercavernous sinuses.(F) Superior Sagiral Sinus (with): Through the superficial middleCerebrat vein and superioranastomotic vein.FACTORS REGULATING THE BLOOD FLOWThe blood flow of cavernous Sinus is regulated by expansilepulsation of internal carotid artery,, by gravity and changeof position of the head.DEVELOPMENTEach sinus is developed from the Cephalie part of primary head veinwhich is the rostral continuation of anterior cardinal vein.Incorporation of plexiform tributaries during the developmentsof sirus makes its interior trabeculated