Gross Anatomy of Brain/Cranial Nerves Flashcards
What are the 3 main regions of the brain?
Cerebrum
Cerebellum
Brainstem
What lobes contribute to the cerebrum?
Frontal
Parietal
Occipital
Temporal
What are 3 regions of the brainstem?
Midbrain
Pons
Medulla Oblongata
What does the central sulcus separate?
Frontal lobes and parietal lobes
Where is the lateral sulcus?
Inferior to frontal and parietal lobes
Which region is continuous with the spinal cord?
Medulla Oblongata
What does the longitudinal cerebral fissure separate?
The 2 cerebral hemispheres
What is the clivus?
Bony landmark anterior to foramen magnum
Where does the midbrain lie?
Junction of middle and posterior cranial fossae
Where does the pons lie?
Anterior aspect of posterior cranial fossa
Where does the medulla oblongata lie?
Posterior cranial fossa; continuous with spinal cord
What is CN I called, and what is its role?
Olfactory Nerve
Sensory - Smell
What is CN II called, and what is its role?
Optic nerve
Sensory - Vision
What is CN III called, and what is its role?
Oculomotor nerve
Motor - Extrinsic muscles of eye (SR, IR, MR, IO, LP)
Motor - Ciliary muscles and sphincter pupillae
What is CN IV called, and what is its role?
Trochlear nerve
Motor - Extrinsic muscle of eye (SO)
What is CN V called, and what is its role?
Trigeminal nerve
Sensory - face; oral, nasal and sinus mucosa; teeth; anterior 2/3 of tongue
Motor - muscles of mastication (temporalis, masseter, medial/lateral pterygoid muscles, mylohyoid, anterior belly of digastric, tensor veli palatini, tensor tympani)
What is CN VI called, and what is its role?
Abducent nerve
Motor - Extrinsic muscle of eye (LR)
Where are the olfactory bulb/tract located?
In contact with inferior/orbital surface of frontal lobe of cerebrum
How is the nasal cavity divided?
Superior 1/3 = olfactory area
Inferior 2/3 = respiratory area
Where do olfactory nerves travel?
Pass through tiny foramina in cribiform plate of ethmoid bone
Where does CN II exit the orbit?
Via optic canal (sphenoid in lesser wing and body) to enter middle cranial fossa
How does CN II travel?
2 optic nerves join forming the optic chiasm before dividing into two optic tracts
Where does CN III emerge?
Midbrain
Where does the CN III travel?
Through cavernous sinus, and exits cranial cavity via superior orbital fissure
Which muscles regulate pupil size? What systems are they innervated by?
Pupillary sphincter (parasympathetic) Pupillary dilator (sympathetic)
What type of information does the oculomotor nerve carry?
Parasympathetic information
How does the oculomotor nerve contribute to intra-ocular muscles?
Sphincter pupillae (constriction of pupil) Ciliary muscle (accomodation, or rounded lens, for near vision)
Where does the CN IV emerge from the brain?
Posterior surface of midbrain
How does CN IV travel?
Passes anteriorly around brainstem (specifically, pons), through cavernous sinus, exits cranial cavity and enters orbit via superior orbital fissure
Where does CN VI emerge from the brain?
From brainstem between pons and medulla
Where does CN VI travel?
Through cavernous sinus, exits cranial cavity and enters orbit via superior orbital fissure
Where does the trigeminal nerve emerge from the brain?
Lateral aspect of pons - large sensory root; small motor root
What are the three branches of the trigeminal nerve?
Ophthalmic nerve (CN V1) Maxillary nerve (CN V2) Mandibular nerve (CN V3)
Where does the ophthalmic nerve exit the cranial cavity?
Superior orbital fissure
Where does the maxillary nerve exit the cranial cavity?
Foramen rotundum
Where does the mandibular nerve exit the cranial cavity?
Foramen ovale
Which cranial nerves pass through the superior orbital fissure?
Oculomotor nerve
Trochlear nerve
Trigeminal nerve (ophthalmic branch)
Abducent nerve
