DURAL VENOUS SINUSES 3/15/2016 Lufukuja G. 1 The venous sinuses… • The venous sinuses of the cranial cavity are blood-filled spaces situated between the layers of the dura mater they are lined by endothelium. Their walls are thick and composed of fibrous tissue; they have no muscular tissue. The sinuses have no valves. • Absorb the C.S.F through the arachnoid granulation tissue & Receive blood from valveless emissary veins 3/15/2016 Lufukuja G. 2 Classification of Dural sinuses: The venous sinuses are classified into paired and unpaired groups: Unpaired sinuses: 1. Superior sagittal sinus 2. Inferior sagittal sinus 3. Straight sinus 4. Occipital sinus 5. Anterior intercavernous sinus 6. Posterior intercavernous sinus 7. Basilar venous plexus 3/15/2016 Lufukuja G. 3 Paired sinuses: 1. Transverse 2. Sigmoid sinus 3. Cavernous sinus 4. Superior petrosal sinus 5. Inferior petrosal sinus 6. Spheno-parietal sinus 7. Petro-squamous 8. Middle meningeal 3/15/2016 Lufukuja G. 4 Superior sagittal sinus • The superior sagittal sinus lies in the upper fixed border of the falx cerebri. It runs backward and becomes continuous with the right transverse sinus. • The sinus communicates on each side with the venous lacunae. Numerous arachnoid villi and granulations project into the lacunae. The superior sagittal sinus receives the superior cerebral veins. On rare occasion it receives a vein from nasal cavity through patent foramen caecum 3/15/2016 Lufukuja G. 5 Superior sagittal sinus… 3/15/2016 Lufukuja G. 6 Applied anatomy: Thrombosis of the superior sagittal sinus may take place due to spread of infection from the nose, scalp and diploic tissue 3/15/2016 Lufukuja G. 7 The inferior sagittal sinus • The inferior sagittal sinus lies in the free lower margin of the falx cerebri. It runs backward and joins the great cerebral vein to form the straight sinus. It receives cerebral veins from the medial surface of the cerebral hemisphere 3/15/2016 Lufukuja G. 8 3/15/2016 Lufukuja G. 9 The straight sinus • The straight sinus, also known as tentorial sinusi it receives blood from the superior cerebellar veins and inferior sagittal sinus and drains into the confluence of sinuses 3/15/2016 Lufukuja G. 10 The transverse sinuses • The transverse sinuses (left and right lateral sinuses), within the human head, are two areas beneath the brain which allow blood to drain from the back of the head. • They run laterally in a groove along the interior surface of the occipital bone. They drain from the confluence of sinuses (by the internal occipital protuberance) to the sigmoid sinuses, which ultimately connect to the internal jugular vein. 3/15/2016 Lufukuja G. 11 The sigmoid sinuses • The sigmoid sinuses, also known as the pars sigmoid, are venous sinuses within the skull that receive blood from posterior dural venous sinus veins. • Each sinus turns downward behind the mastoid antrum of the temporal bone and then leaves the skull through the jugular foramen to become the internal jugular vein Applied anatomy: Thrombosis of sigmoid sinus may take place from the infected middle ear or mastoid antrum 3/15/2016 Lufukuja G. 12 The occipital sinus • The occipital sinus lies in the attached margin of the falx cerebelli. It communicates with the vertebral veins through the foramen magnum and the transverse sinuses 3/15/2016 Lufukuja G. 13 The cavernous sinus • Each cavernous sinus lies on the lateral side of the body of the sphenoid bone. Anteriorly, the sinus receives the inferior ophthalmic vein and the central vein of the retina. The sinus drains posteriorly into the transverse sinus through the superior petrosal sinus. Intercavernous sinuses connect the two cavernous sinuses through the sella turcica • Important Structures Associated With the Cavernous Sinuses :The internal carotid artery and the sixth cranial nerve, which travel through it • In the lateral wall, the third and fourth cranial nerves, and the ophthalmic and maxillary divisions of the fifth cranial nerve. The pituitary gland, which lies medially in the sella turcica. 3/15/2016 Lufukuja G. 14 3/15/2016 Lufukuja G. 15 3/15/2016 Lufukuja G. 16 Anterior and posterior intercavernous sinus: Each sinus traverse respectively along the anterior and posterior attached margin of diaphragma sellae and connects the cavernous sinus of both side 3/15/2016 Lufukuja G. 17 3/15/2016 Lufukuja G. 18 Basilar venous plexus: It is a plexiform venous network and lies on the clivus of the skull 3/15/2016 Lufukuja G. 19 Applied anatomy: The veins of the face, which are connected with the cavernous sinus via the facial vein and inferior ophthalmic vein, and are an important route for the spread of infection from the face The superior and inferior petrosal sinuses, which run along the upper and lower borders of the petrous part of the temporal bone 3/15/2016 Lufukuja G. 20 Superior petrosal sinus sinus: Conveys the blood from the cavernous sinus to the transverse sinuses It is situated in lateral attached border of tentorium cerebelli Tributaries: Inferior cerebral veins Some cerebellar veins Veins from the tympanic cavity 3/15/2016 Lufukuja G. 21 Inferior petrosal sinus: Drains the blood from cavernous sinus into the superior bulb of internal jugular vein Tributaries: Labyrinthine veins from the cochlear cannaliculi and aqueduct of vestibule Veins from the medulla, pons and cerebellum 3/15/2016 Lufukuja G. 22 Applied anatomy: Thrombosis of inferior petrosal sinus may occur from the infection of middle and internal ear, with ipsilateral involvement of trigeminal and abducent nerves 3/15/2016 Lufukuja G. 23 The skull & foramina Lufukuja G. 24 Lufukuja G. 25 Lufukuja G. 26 Lufukuja G. 27 Cranial foramina • The human skull has numerous holes (foramina) through which cranial nerves, arteries, veins and other structures pass. Lufukuja G. 28 Cranial foramina… • Frontal bone - supraorbital foramen 1. supraorbital artery, 2. supraorbital vein 3. supraorbital nerve • foramen cecum 1. emissary veins to superior sagittal sinus Lufukuja G. 29 Cranial foramina… • Ethmoid bone - foramina of cribriform plate – 1. olfactory nerve bundles (I) • anterior ethmoidal foramen 1. anterior ethmoidal artery 2. anterior ethmoidal vein 3. anterior ethmoidal nerve • posterior ethmoidal foramen 1. posterior ethmoidal artery 2. posterior ethmoidal vein 3. posterior ethmoidal nerve Lufukuja G. 30 Cranial foramina… • Optic canal 1. Ophthalmic artery optic nerve (II) • superior orbital fissure 1. superior ophthalmic vein 2. oculomotor nerve (III) 3. trochlear nerve (IV) 4. lacrimal, frontal and nasociliary branches of ophthalmic nerve (V1) 5. abducent nerve (VI) sphenoid middle cranial fossa foramen rotundum - maxillary nerve (V2) maxilla Lufukuja G. 31 Cranial foramina… • Incisive foramen/incisive canal 1. sphenopalatine artery 2. nasopalatine nerve(V2) palatine • greater palatine foramen 1. greater palatine artery 2. greater palatine vein 3. greater palatine nerve palatine • lesser palatine foramina 1. lesser palatine artery 2. lesser palatine vein 3. lesser palatine nerve sphenoid and maxilla Lufukuja G. 32 Cranial foramina… • Inferior orbital fissure 1. inferior ophthalmic veins 2. infraorbital artery 3. infraorbital vein 4. zygomatic nerve and infraorbital nerve of maxillary nerve (V2) orbital branches of pterygopalatine ganglion • Infraorbital foramen 1. infraorbital artery 2. infraorbital vein 3. infraorbital nerve Lufukuja G. 33 Cranial foramina… • foramen ovale 1. mandibular nerve 2. accessory meningeal artery (V3) 3. lesser petrosal nerve (occasionally) • foramen spinosum 1. middle meningeal artery 2. meningeal branch of the mandibular nerve (V3) • foramen lacerum 1. artery of pterygoid canal 2. nerve of pterygoid canal Lufukuja G. 34 Cranial foramina… • Internal acoustic meatus 1. labyrinthine artery 2. facial nerve (VII), 3. vestibulocochlear nerve (VIII) • Jugular foramen 1. internal jugular vein, 2. inferior petrosal sinus, 3. sigmoid sinus 4. glossopharyngeal nerve (IX), 5. vagus nerve (X), 6. accessory nerve (XI) Lufukuja G. 35 Cranial foramina… • Hypoglossal canal – 1. hypoglossal nerve (XII) • Foramen magnum 1. anterior and posterior spinal arteries, 2. vertebral arteries 3. medulla oblongata, 4. ascending spinal fibers of accessory nerve (XI) • Stylomastoid foramen 1. stylomastoid artery facial nerve (VII) Lufukuja G. 36 Lufukuja G. 37 Lufukuja G. 38 Lufukuja G. 39 Lufukuja G. 40 Lufukuja G. 41 Lufukuja G. 42 Lufukuja G. 43 Lufukuja G. 44 Lufukuja G. 45 Lufukuja G. 46 3/15/2016 Lufukuja G. 47