through what foramen does the medulla pass to form the spinal cord
foramen magnum
what does the open part of the medulla “open” into
4rth ventricle
the middle cerebellar peduncle consists of what fibers?
motor fibers
what part of the brain lies superior to the midbrain
diencephalon
what lies immediately inferior to the midbrain
pons
what separates the two hemispheres of the brain
the median longitudinal fissure
what is the ventricular space that lies immediately anterior to the cerebellum
the cerebellar aqueduct
the corpus callosum consists of what fibers?
commissural fibers
the primary motor cortex is the
frontal lobe
the primary visual cortex is the
occipital lobe
the primary sensory cortex is the
parietal lobe
the primary auditory cortex is the
temporal lobe
at what level does the spinal cord terminate
L1/L2
what spinal level in a child ends
L3
the dura mater and arachnoid mater ends at what vertebral level
S2
the pia mater ends with the
filum terminale
what level is a lumbar puncture on an adult
L3/4
how many pairs of spinal nerves are there
31
what are the arteries in the circle of willis
anterior cerebral artery, anterior communicating artery, ophthalmic artery, internal carotids, middle cerebral, posterior communicating artery, posterior cerebral artery, superior cerebral, basilar, labyrinthine artery, arterior inferior cerebller artery, posterior inferior artery,, vertebral artery, anterior spinal artery.
the left and right vertebral arteries arise from
subclavian
the left and right internal carotid arteries arise from
C4
the primary motor cortex is supplied by what artery?
anterior/middle cerebral
the primary sensory area is supplied by what cerebral arteries?
mostly middle cerebral, some anterior
primary visual cortex is supplied by what cerebral artery?
posterior cerebral
primary auditory area is supplied by what cerebral artery
middle
area for olfaction is supplied by what cerebral artery
middle
the vertebro-basilar system supplies
cerebellum and brainstem
what cranial nerve emerges just above the superior cerebellar artery
oculomotor
sympathetic innervation arises for the brain
superior cervical ganglion around the internal carotid
the pressure receptor along the blood supply to for the brain is
the carotid sinus along the glossopharyngeal and vagus nerve
the chemorecptor along the blood supply for the brain is the
carotid body along the glossopharyngeal nerve
dural venous sinuses drain into
internal jugular vein
the internal jugular vein passes through the
jugular foramina
the superior ophthalmic vein route
the facial vein is continuous with the superior ophthalmic vein which drains into the cavernous sinus within the cranial cavity
the inferior petrosal sinuses lies at the base of the brain and communicates with
the basilar sinus and communicates with the internal vertebral sinus
the posterior spinal artery is branches of
posterior inferior cerebellar artery
in the epidural space what is present
internal vertebral (epidural) venous plexus
what is structure is present within the subarachnoid psace
connective tissue trabeculae
the falx cerebri seperates the
the cerebrum hemispheres
the falx cerebri attaches to t
crista gali and the internal occipital protuberance
the upper border of the falx cerebri contians
superior sagittal sinus
the lower border of the falx cerebri contains
inferior sagittal sinus
what structures surround the tentorium cerebelli
tranverse sinus, cerebellum and cerebrum
the anterior edge of the tentorium cerebelli attaches to
posterior clinoid processes
the dural venous that runs along the atachment of falx cerebri to the tentorium is the
straight sinus
the fold of dura that surrounds the pituitary stalk is called
the diaphragma sellae
the middle meningeal artery is a branch of
the maxillary
the meningeal artery enters the cranial cavity through
the foramen spinosum
CSF is produced by
the choroid plexus
CSF passes through the 4rth ventricle into the subarachnoid space is through
medial aperture, and left and right apertures
CSf is reabsorbed through the
arachnoid villi in the sagittal sinus
olfactory nerve pathway
receptors in olfactory epithelium of nasal cavity, olfactory nerve fibres pass through foraminifera in cribriform plate of ethmoid bone and enter olfactory bulb in the anterior cranial fossa
components of olfactory nerve
smell
clinical application of olfactory nerve
fractured cribriform plate may tear olfactory nerve fibres causing anosmia
optic nerve pathway
enters via optic canal, nerves join to form optic chiasm, fibres from medial (nasal) half of each retina cross to form optic tract
optic nerve component
vision
clinical applications of optic nerve
papilloedema, blindness, hemianopsia
oculomotor nerve pathway
emerges from midbrain and exits via superior orbital fissure
oculomotor nerve components
somatic motor - extraocular muscles (superior, medial & inferior rectus and inferior oblique) and eyelid (levator palpebrae superioris)
visceral motor - parasympathetic to pupil causing constriction and to ciliary muscle causing accommodation of the lens
clinical applications of oculomotor nerves
drooping of upper eyelid (ptosis)
eyeball abducted and pointing down
no pupillary reflex
no accommodation of the lens
trochlear nerve pathway
emerges from dorsal surface of the mid brain and exits via the superior orbital fissure
components of trochlear nerve
somatic motor - extraocular muscle (superior oblique turns eye downwards)
clinical application of trochlear nerve
diplopia
abducent nerve pathway
emerges between pons and medulla and exits exits via the superior orbital fissure
abducent nerve components
somatic motor - extraocular muscle (lateral rectus abducts the eye)
clinical application of abducent nerve
medial deviation of the affected eye causing diplopia
ophthalmic nerve pathway
emerges from the pons, travels through the trigeminal ganglion and exits via the superior orbital fissure
components of ophthalmic nerve
General sensory - from cornea, forehead, scalp, eyelids, nose and mucosa of nasal cavity and sinuses
maxillary nerve pathway
emerges from the pons, travels through the trigeminal ganglion and exits via the foramen rotundum
components of maxillary nerve
General sensory - from face over maxilla, maxillary teeth, temperomandibular joint, mucosa of nose, maxillary sinuses and palate
pathway of mandibular nerve
emerges from the pons, travels through the trigeminal ganglion and exits via the foramen ovale
components of mandibular nerve
General sensory - from face over mandible, mandibular teeth, temperomandibular joint, mucosa of mouth & anterior 2/3rds of tongue
Somatic motor - muscles of mastication, part of digastric, tensor veli palatinin & tensor tympani
trigeminal nerve clinical applications
paralysis of muscles of mastication
loss of corneal or sneezing reflex
loss of sensation in the face
trigeminal neuralgia
facial nerve pathway
emerges between pons and medulla and exits via internal acoustic meatus, facial canal and stylomastoid foramen
components of facial nerve
somatic motor - muscles of facial expression & scalp, stapedius of middle ear, part of digastric muscle
visceral motor - parasympathetic innervation of submandibular & sublingual salivary glands, lacrimal glands, glands of nose & palate
special sensory - taste from anterior 2/3rd of tongue & soft palate
general sensory - from external acoustic meatus
clinical application of facial nerve
most frequently injured - due to long pathway through bone
Bell’s palsy - cannot frown, close eyelid, or bare teeth
pathway of vestibulocochlear nerve
emerges from between pons and medulla and exits via internal acoustic meatus, dividing into vestibular & cochlear nerves
components of vestibulocochlear nerve
special sensory - vestibular sensation from semicircular ducts, utricle, saccule gives sense of position & movement
- hearing from spiral organ
clinicla applications of vestibulocochlear nerve
tinnitus (ringing in the ears)
deafness (conductive vs sensorineural)
vertigo (loss of balance)
nystagmus (involuntary rapid eye movements)
pathway of glossopharyngeal nerve
emerges from medulla and exits via jugular foramen
components of glossopharyngeal nerve
special sensory - taste from posterior 3rd of tongue
general sensory - cutaneous sensations from middle ear and posterior oral cavity
visceral sensory - sensation from carotid body & carotid sinus
visceral motor - parasympathetic innervation of parotid gland
somatic motor - to stylopharyngeus, helps with swallowing
clinical applications of glossopharyngeal
loss of gag reflex and taste from back of tongue
associated with injuries to CNs X and XI - jugular foramen syndrome
vagus nerve pathway
emerges from medulla and exits via jugular foramen, then everywhere!
components of vagus nerve
special sensory - taste from epiglottis and palate
general sensory - sensation from auricle, external acoustic meatus
visceral sensory - from pharnyx, larynx, trachea, bronchi, heart, oesophagus, stomach, intestine
visceral motor - parasympathetic innervation muscle in bronchi, gut, heart
somatic motor - to pharynx, larynx, palate & oesophagus
clinical application of vagus
damage to pharyngeal branches cause difficulty in swallowing
damage to laryngeal branches causes difficulty in speaking
accessory nerve pathway
small cranial (medulla) and large spinal roots exit via jugular foramen
components of accessory nerve
somatic motor - striated muscle of soft palate, pharynx & larynx, and to sternocleidomastoid & trapezius
application of accessory nerve
weakness in turning head and shrugging shoulder
pathway of hypoglossal nerve
emerges from medulla and exits through the hypoglossal canal
components of hypoglossal nerve
somatic motor - to muscles of tongue
clinical application of hypoglossal nerve
vulnerable to damage during tonsillectomy
causes paralysis & atrophy of ipsilateral half of tongue. Tip deviates towards affected side
vertebral arteries route
– right and left arise from the subclavian arteries ascending via the transverse processes of the cervical vertebrae entering through the foramen magnum. They then branch of to give the meningeal branch to supply the falx cerebelli, anterior and posterior spinal arteries to supply the spinal cord and the posterior inferior cerebellar artery. Finally both merge to form the basilar artery which bifurcates into the posterior cerebral arteries.
cerebellum blood supply is from the
posterior inferior cerebellar artery
structures that traverse through the cavernous sinus
abducen’s nerve
carotid plexus
internal carotid artery
travels through the lateral wall of the cavernous sinus
oculomotor nerve, trochlear nerve, ophthalmic nerve and maxillary branches of the trigeminal
what are the four folds of the dura
tentorium cerebri
falx cerebri
falx cerebelli
diaphragma sellae
falx cerebelli attachments
internal occipital crest to projecting between the two hemispheres of the cerebellum
diaphragma sellae is
small circular fold of dura forms the roof of the sella turica
extradural haematoma cause
blood pools between skull and dura usually from meningeal artery
subdural haematoma cause
venous blood collects between dura and arachnoid mater form cerebral vein damage
CSF is produced from
plasma
association fibre example
connects cortical areas, includes the fornix connecting the hippocampus to the mamillary body
septum pellucidum is the
thin triangular vertical double membrane separating the anterior horns of the left and right lateral ventricles of the brain its runs as a sheet from the corpus callosum down to the fornix.
what are the four parts of the corpus callosum
Rostrum, Genu, body, Splenium
Rostrum of the corpus callosum connects
orbital frontal lobes
Genu of the anterior corpus callosum connects
frontal lobes
body of the corpus callosum connects
superficial surfaces of the cerebrum via the corona radiata
body of the corpus callosum connects the
two occipital lobes
internal capsule blood supply is from
middle cerebral artery
cerebellum grey matter organisation
located on the surface of the cerebellum, tightly folded forming the cerebellar cortex
cerebellum white matter organisation
located underneath the cerebellar cortex embedding the four cerebellar nuclei
lateral horns of the spinal cord are located between which vertebrae?
T1-L2 and S2-S4
ascending white matter functional tracts of the spinal cord
Dorsal column for sensory of fine touch, vibration and proprioception
anterolateral system; anterior spinothalamic (crude touch, pressure) and the lateral spinothalamic tract (pain and temperature)
spinocerebellar tracts; proprioception
descending pyramidal tracts of the spinal cord
corticospinal tract – supplies musculature of the body
corticobulbar tract – musculature of head and neck
descending extrapyramidal tracts of the spinal cord
vestibulospinal – balance and posture
reticulospinal - medial pons (facilitates voluntary movement) lateral medulla (inhibits voluntary movement)
rubrospinal tracts – red nucleus mid brain for fine control of hand movement
tectospinal tracts – coordinates head to vision stimulus