Cranial Nerves and Intracranial Cavity Flashcards
cerebral hemispheres
right and left
are joined across the midline
corpus callosum
two cerebral hemispheres communicate with one another
made up of fibers (axons) of nerve cells which cross the midline and convey information from one hemisphere to the other
gyri and sulci
gyri: ridges on surface of brain
sulci: separates the ridges by grooves
may be used as landmarks to divide the cerebral hemispheres into four lobes
the 4 lobes are named for the bones of the skull beneath which they lie
frontal lobe
parietal lobe
occipital lobe
temporal lobe
interior of skull is divided into
three depressions: anterior cranial fossa, middle cranial fossa, posterior cranial fossa
each fossa is perforated by holes for
passage of nerves and vessels
anterior cranial fossa
formed by frontal, ethmoid, sphenoid bones; houses frontal lobes
middle cranial fossa
formed by sphenoid and temporal bones; houses portions of temporal lobes
posterior cranial fossa
formed by sphenoid, temporal and occipital bones; houses cerebellum and brain stem
cranial nerves leave the skull through various ______ in the bones of the skull
foramina
foramina
the passage of cranial nerves
orbit canal
foramen in sphenoid bone for passage of optic nerve CN II
superior orbital fissure
slit in sphenoid bone for passage of CN III, CN IV, ophthalmic division of CN V (V1) and CN VI
CN I
olfactory nerve
CN II
optic nerve
CN III
oculomotor nerve
CN IV
trochlear nerve
CN V
trigeminal nerve
CN VI
abducens nerve
olfactory nerve is responsible for
smell
optic nerve is responsible for
vision
oculomotor nerve is responsible for
eye movement, pupillary constriction
trochlear nerve is responsible for
eye movement
trigeminal nerve is responsible for
sensory to face, teeth, motor to muscle of mastication
abducens nerve is responsible for
eye movements
trigeminal nerve (CN V) gives rise to 3 divisions
ophthalmic
maxillary
mandibular
the 3 divisions of the CN V supply nerves for
ophthalmic and maxillary divisions are entirely sensory
mandibular includes sensory fibres and motor fibres to muscles of mastication
maxillary and mandibular divisions supply sensation, including pain, to teeth and gingiva
CN VII
facial nerve
CN VIII
vestibulocochlear
CN IX
glossopharyngeal nerve
CN X
vagus nerve
CN XI
spinal accessory nerve
CN XII
hypoglossal nerve
facial nerve is responsible for
taste, motor control of muscles of facial expression
vestibulo-cochlear is responsible for
hearing and balance
glossopharyngeal nerve is responsible for
taste, sensory to pharynx and tongue
vagus nerve is responsible for
general visceral sensation, motor control of heart, larynx, pharynx, parasympathetic control of smooth muscle of gut
spinal accessory nerve is responsible for
motor to 2 muscles (sternocleidomastoid, trapezius)
hypoglossal nerve is responsible for
motor to tongue muscles
brain is wrapped in three meningeal layers
dura mater
arachnoid
pia mater
dura mater
outermost and thickest
arachnoid
attached to undersurface of dura; separated from pia by subarachnoid space
pia mater
innermost layer, attached to surface of brain
what are dural reflections and the main ones
folds of dura mater
falx cerebri: separates L and R cerebral hemispheres
tentorium cerebelli: covers cerebellum and separates it from occipital lobes
what are dural venous sinuses
are intracranial channels between layers of dura mater
they drain blood from the brain and mainly empty into the internal jugular vein
dural venous sinuses order
superior sagittal sinus
inferior sagittal sinus
straight sinus
transverse sinus
sigmoid sinus
cavernous sinus
cavernous sinus
one of the dural venous sinuses of the head
a network of veins that sits on both sides of the body of the sphenoid bone
the structures that pass through the cavernous sinus are
cranial nerve III
CN IV
CN V (branches V1 and V2)
CN VI
internal carotid artery
what lies between the two cavernous sinuses and sits on the bony sella turcica
the pituitary gland
lesions or infections affecting the cavernous sinus may affect the _____ traversing through it
nerves
