Cranial Cavity & Pituitary Gland PDF

DR.Hendawy DR.Hendawy “cranial cavity”  Dural folds “Replication of inner meningeal layer of dura matter” Diaphragma sellae Shape: Circular Site: Above pituitary gland Attachment:...

DR.Hendawy DR.Hendawy “cranial cavity”  Dural folds “Replication of inner meningeal layer of dura matter” Diaphragma sellae Shape: Circular Site: Above pituitary gland Attachment: DR.Hendawy o Anteriorly: attached to tuberculum sellea o Posteriorly: attached to dorsum sellea o Has central hole which transmit infundibulum of pitutary gland Related sinuses: Inter-Cavernous sinuses Tentorium cerebelli Shape: tent-shaped Site: between cerebral & cerebellar hemispheres Attachment: o Superior Surface: Attached to base of Falx Cerebri o Inferior Surface: Attached to base of Falx Cerebelli o Free Border: U-Shaped around midbrain. It is attached to anterior clenoid process o Attached Border: Attached to Posterior Clenoid Process & Superior Petrosal Sulcus & Transverse Sulcus Related sinuses: o Straight sinus: At base of Falx Cerebri o Superior petrosal sinus: Along Superior Petrosal Sulcus o Transverse sinus: Along transverse sulcus DR.Hendawy “cranial cavity”  Falx cerebri Shape: sickle-shaped Site: between 2 cerebral hemispheres Attachment: o Apex: Attached to Frontal Crest & Crista Galli o Base: Attached to upper surface of Tentorium Cerebelli o Upper border: Related to Sagittal Sulcus o Lower border: free DR.Hendawy Related sinuses: o Superior Sagittal sinus: At upper margin o Inferior Sagittal sinus: At posterior 2/3 of lower margin o Straight sinus: At base of falx Cerebri Falx cerebelli Shape: inverted triangle Site: between 2 cerebellar hemispheres Attachment: o Apex: Attached to posterior border of Foramen magnum o Base: Attached to inferior Surface of Tentorium Cerebelli o Anterior border: Free o Posterior border: Attached to internal occipital crest Related sinuses: Occipital sinus: along internal occipital crest Cavum trigeminal “enclose trigeminal ganglion” DR.Hendawy “cranial cavity”  Dural sinuses Valueless Venous channels between 2 layers of dura matter Single sinuses Superior Sagittal Sinus Begin: At Foramen Caecum Site upper convex border of the falx cerebri End: it forms right transverse sinus DR.Hendawy Inferior Sagittal Sinus Site: At posterior 2/3 of lower border of falx cerebri End: Unit with great cerebral vein to form straight sinus Straight Sinus Begin Union of great cerebral vein with inferior sagittal sinus End: it forms left transverse sinus Occipital Sinus Beginning: From confluence of sinuses End: it bifurcates at foramen magnum to end in sigmoid sinus Basilar plexus of Veins Site: Over clavius Connect inferior petrosal sinuses Inter-Cavernous Sinuses Site  Anterior& posterior sinuses run in borders of diaphragma sellae  Middle sinus run below pituitary gland Connect: Cavernous Sinuses of both sides DR.Hendawy “cranial cavity”  Paired sinuses Spheno-Parietal Sinus Site: passes along posterior border of lesser wing of sphenoid End: in cavernous sinus Cavernous Sinus Relation o Anterior: Superior Orbital Fissure DR.Hendawy o Posterior: Apex of petrous temporal o Medial: Pitutary gland & body of phenoid o Lateral: temporal lobe of brain Tributaries: o Ophthalmic veins & central vein of retina & spheno-parietal sinus o Inter-cavernous sinues o Inferior cerebral & superficial middle cerebral vein o Emissary vein passing in foramen lacerum connecting it with pharyngeal plexus o Emissary vein passing in foramen ovale connecting it with pterygoid plexus Content o Lateral wall “from above downward”: “Occulomotor & Trochlear & Ophthalmic & Maxillary nerves” o Floor: Internal Carotid artery & Abducent nerve “infrolateral to internal carotid” Drainage o Superior Petrosal Sinus: end in transverse Sinus o Inferior Petrosal Sinus: end in internal jugular vein DR.Hendawy “cranial cavity” Dangerous area of the face: o It is the area drained by anterior facial vein including nose &upper lip o Infection can spread from this part to cavernous sinus causing thrombosis through 2 ways:  Directly: by connection of anterior facial vein with cavernous sinus through superior ophthalmic vein  Indirectly: by connection of anterior facial vein to pterygoid plexus via deep facial vein and then pterygoid plexus is connected to cavernous sinus via emissary vein passing through foramen ovale Superior Petrosal Sinus Site: pass in superior petrosal sulcus DR.Hendawy Beginning: Cavernous sinus End At junction between transverse & sigmoid sinus Inferior Petrosal Sinus Site: Petro-occipital sulcus Beginning: Cavernous sinus End: passes in jugular foramen to end in internal jugular vein Transverse Sinus Site: passes along transverse sulcus Begin Right sinus: is superior sagittal sinus continuation & Left sinus: straight sinus continuation End: Form sigmoid sinus Sigmoid Sinus Site: passes in sigmoid sulcus Begin: Continuation of transverse sinus End: pass through jugular foramen to form internal jugular vein DR.Hendawy “cranial cavity”  Pituitary gland (hypophysis cerebri) Lobes:  Anterior lobe “adeno-hypophysis”  Upper part gives a projection called “pars tuberalis”  Lower part divided by pituitary cleft into: “pars distalis” & “pars intermedia”  Posterior lobe “neuro- hypophysis”: Connected to hypothalamus by infundibulum DR.Hendawy Relations:  Superiorly  diaphragma sellae & optic chiasma  Inferiorly  body of sphenoid & shpenoidal sinuses.  Anteriorly tuberculum sellae & anterior intercavernous sinus  Posteriorly  dorsum sellae & posterior intercavernous sinus  On each side  cavernous sinus. Arterial supply: superior & inferior hypophyseal arteries from internal carotid artery Venous drainage: drain into cavernous & inter-cavernous sinuses DR.Hendawy “cranial cavity” Development Origin:  Neurohypophysis “posteriorlobe”: Develops as down-growth diverticulum from the floor of diencephalon  Adenohypophysis “anterior lobe”: Develops as up-growth pouch from the roof of stomodeum “Rathke’s pouch”. The vesicle differentiates into:  Anterior wall: become pars distalis  Posterior wall: become pars intermedia  Pars tuberalis: wraps around the infundibulum.  The cavity forms cleft. Anomalies  Aplasia or hypoplasia: due to non or abnormal development Rathke's pouch.  Pharyngeal pituitary gland: Accessory masses of anterior lobe tissue develop in the roof of oropharynx.  Craniopharyngeoma “congenital tumor of pituitary gland”  Ectopic pituitary gland. DR.Hendawy “cranial cavity”