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Questions and Answers
The internal carotid artery divides into its terminal branches at the posterior perforated substance.
The internal carotid artery divides into its terminal branches at the posterior perforated substance.
False (B)
The anterior communicating artery is located in the suprachiasmatic cistern, lying vertically above the prechiasmatic groove between the two optic canals.
The anterior communicating artery is located in the suprachiasmatic cistern, lying vertically above the prechiasmatic groove between the two optic canals.
False (B)
The ophthalmic artery branches from the internal carotid immediately above the floor of the cavernous sinus.
The ophthalmic artery branches from the internal carotid immediately above the floor of the cavernous sinus.
False (B)
The optic nerve slopes forward, up, and medially from the chiasma to the optic canal.
The optic nerve slopes forward, up, and medially from the chiasma to the optic canal.
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The intracranial part of the optic nerve, within the chiasmatic cistern, is supplied by branches of the posterior cerebral artery.
The intracranial part of the optic nerve, within the chiasmatic cistern, is supplied by branches of the posterior cerebral artery.
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The oculomotor nerve exits the medial side of the cerebral peduncle's crus and travels between the anterior cerebral and superior cerebellar arteries.
The oculomotor nerve exits the medial side of the cerebral peduncle's crus and travels between the anterior cerebral and superior cerebellar arteries.
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Parasympathetic preganglionic fibers for the pupil are located on the inner part of the oculomotor nerve as it enters the cavernous sinus.
Parasympathetic preganglionic fibers for the pupil are located on the inner part of the oculomotor nerve as it enters the cavernous sinus.
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Damage to the parasympathetic fibers of the oculomotor nerve due to arteriosclerotic infarction will always affect pupillary function.
Damage to the parasympathetic fibers of the oculomotor nerve due to arteriosclerotic infarction will always affect pupillary function.
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The trochlear nerve emerges from the ventral surface of the brainstem.
The trochlear nerve emerges from the ventral surface of the brainstem.
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The trochlear nerve enters the middle fossa just posterior to the trigeminal nerve.
The trochlear nerve enters the middle fossa just posterior to the trigeminal nerve.
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The abducent nerve exits the anterior cranial fossa by traversing the apex of the petrous temporal bone.
The abducent nerve exits the anterior cranial fossa by traversing the apex of the petrous temporal bone.
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The posterior communicating artery is situated within the cerebellopontine angle cistern.
The posterior communicating artery is situated within the cerebellopontine angle cistern.
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The trigeminal ganglion is positioned superior to the dura mater in the middle cranial fossa.
The trigeminal ganglion is positioned superior to the dura mater in the middle cranial fossa.
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The trigeminal nerve traverses the upper border of the petrous bone, leaving a groove approximately 25 mm wide.
The trigeminal nerve traverses the upper border of the petrous bone, leaving a groove approximately 25 mm wide.
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The greater petrosal nerve is situated above the trigeminal cave, positioned between two dural layers.
The greater petrosal nerve is situated above the trigeminal cave, positioned between two dural layers.
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The trigeminal cave opens anteriorly into the middle cranial fossa.
The trigeminal cave opens anteriorly into the middle cranial fossa.
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The primary blood supply to the trigeminal ganglion is exclusively from ganglionic branches of the external carotid artery.
The primary blood supply to the trigeminal ganglion is exclusively from ganglionic branches of the external carotid artery.
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The meningeal branch of the facial nerve (nervus spinosus) provides nerve supply to the epineurium of the trigeminal ganglion.
The meningeal branch of the facial nerve (nervus spinosus) provides nerve supply to the epineurium of the trigeminal ganglion.
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The mandibular division of the trigeminal nerve passes medially to descend through the foramen rotundum.
The mandibular division of the trigeminal nerve passes medially to descend through the foramen rotundum.
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The lesser petrosal nerve emerges through the foramen spinosum to merge with the otic ganglion.
The lesser petrosal nerve emerges through the foramen spinosum to merge with the otic ganglion.
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Flashcards
Internal carotid artery
Internal carotid artery
Major artery supplying blood to the brain, emerges medial to anterior clinoid process.
Carotid siphon
Carotid siphon
The curve of the internal carotid artery seen in a lateral view, resembling a sideways U.
Anterior cerebral artery
Anterior cerebral artery
Branch of the internal carotid artery that supplies the anterior part of the brain.
Anterior communicating artery
Anterior communicating artery
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Ophthalmic artery
Ophthalmic artery
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Optic canal
Optic canal
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Oculomotor nerve
Oculomotor nerve
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Trochlear nerve
Trochlear nerve
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Interpeduncular cistern
Interpeduncular cistern
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Parasympathetic fibers
Parasympathetic fibers
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Abducent nerve
Abducent nerve
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Trigeminal ganglion
Trigeminal ganglion
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Trigeminal cave (of Meckel)
Trigeminal cave (of Meckel)
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Greater petrosal nerve
Greater petrosal nerve
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Accessory meningeal artery
Accessory meningeal artery
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Mandibular division of trigeminal nerve
Mandibular division of trigeminal nerve
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Foramen ovale
Foramen ovale
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Maxillary nerve
Maxillary nerve
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Cavernous sinus
Cavernous sinus
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Lesser petrosal nerve
Lesser petrosal nerve
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Study Notes
Internal Carotid Artery
- Emerges from cavernous sinus, medial to anterior clinoid process
- Curves backward, then upward, lateral to optic chiasma
- Divides into terminal branches (anterior cerebral artery, anterior communicating artery)
- "Carotid siphon" is the curve of the artery in the cavernous sinus
Ophthalmic Artery
- Branches from internal carotid above cavernous sinus roof
- Relationship with optic nerve: carotid from below/lateral, optic from above/medial (optic canal)
Optic Nerve
- Slopes forward, down, laterally from optic chiasma to optic canal
- Covered in pia mater; receives arachnoid and dura mater at optic canal
- Intracranial part gets blood supply from anterior cerebral artery branches
Oculomotor Nerve
- Originates at cerebral peduncle´s medial side
- Passes forward, between posterior cerebral and superior cerebellar arteries, below posterior communicating artery (potential aneurysm vulnerability)
- Crosses interpeduncular cistern, enters middle fossa cavernous sinus roof
- Parasympathetic preganglionic fibers for pupil are on the outer part of the nerve, and damage may occur based on pressure
Trochlear Nerve
- Originates behind inferior colliculus, dorsal brainstem
- Curls around cerebral peduncle, below posterior cerebral artery
- Runs forward, above superior cerebellar artery, lateral to oculomotor nerve
- Enters middle fossa behind oculomotor nerve, pierces dura mater at cavernous sinus roof behind attached/free tentorium cerebelli margin
Abducent Nerve
- Leaves posterior cranial fossa over petrous temporal apex
- Runs around lateral side of ascending internal carotid artery
- Enters cavernous sinus
Posterior Communicating Artery
- Connects internal carotid and posterior cerebral arteries (part of circle of Willis)
- Located in interpeduncular cistern, above and lateral to pituitary gland
Trigeminal Ganglion
- Located beneath dura mater, middle cranial fossa, cavernous sinus floor
- Occupies trigeminal impression on petrous temporal
- Divided into posterior/anterior halves. Posterior half is in the trigeminal cave, a diverticulum of dura and arachnoid. This surrounds the nerve roots and is bathed in CSF
- Anterior half is in the dura of the cavernous sinus' lateral wall.
- Sensory and motor nerve roots and posterior half are enveloped by arachnoid.
Trigeminal Nerve
- Emerges from pons, runs forward, crossing upper petrous bone border
- Leaves a groove (5 mm wide) on the petrous bone before passing under superior petrosal sinus.
- Trigeminal cave located in the middle fossa having an opening into the posterior fossa
Trigeminal Blood Supply
- Ganglionic branches from internal carotid, within cavernous sinus, but the accessory meningeal artery plays a significant role from the foramen ovale to the ganglion.
Trigeminal Nerve Supply
- Epineurium and adjacent dura are supplied by mandibular nerve's meningeal branch (nervus spinosus).
Trigeminal Surgical Approaches
- Accessing the sensory root and posterior part of the ganglion requires entry into the subarachnoid space.
- Anterior portion & divisions can be reached extradurally from floor of the middle fossa, stripping the dura from the bone. This may cause facial palsy due to possible greater petrosal nerve and geniculate ganglion pressure.
Trigeminal Nerve Divisions
- Mandibular: Passes laterally, through foramen ovale, not involving lateral cavernous sinus wall, joined with motor root to form mixed mandibular nerve.
- Maxillary: Passes forward, through foramen rotundum.
- Ophthalmic: Branches forward, via superior orbital fissure.
Greater Petrosal Nerve
- From facial nerve, emerges in petrous bone hiatus.
- Runs between dura layers and beneath trigeminal ganglion.
- Joins deep petrosal nerve (from carotid plexus) to form vidian nerve.
- Enters pterygoid canal through foramen lacerum, runs canal, joins pterygopalatine ganglion.
Lesser Petrosal Nerve
- From glossopharyngeal nerve.
- Leaves petrous bone hiatus and extends beneath middle cranial fossa floor.
- Leaves through foramen ovale (or petrosal foramen) to join otic ganglion.
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Description
This quiz covers the anatomy and relationships of the internal carotid artery, ophthalmic artery, optic nerve, and oculomotor nerve. Test your knowledge on their origins, pathways, and relevant clinical implications. Ideal for students of neurology and anatomy.
