Lab Manual Flashcards
Midline, btw hemispheres; contains flax of cerebrum
Longitudinal fissure
the deep furrow separating the parietal lobe (inferiorly) from the frontal lobe and anterior temporal lobe (superiorly). Divides into 3 branches
Lateral sulcus (Sylvian fissure)
The largest portion of the lateral sulcus, runs posteriorly, ending by turning upward into parietal lobe
Posterior branch
Near the anterior portion of the lateral sulcus, short, runs almost perpendicular from the main lateral sulcus into inferior frontal gyrus
Ascending branch
Anterior to the ascending branch of the lateral sulcus, runs anteriorly into inferior frontal gyrus
Anterior branch
Groove btw frontal and parietal lobe
Central sulcus (Rolando’s fissure)
What lobe is “from frontal pole to central sulcus, superior to lateral sulcus”
Frontal lobe
What lobe is “bounded by central sulcus rostrally and parietooccipital sulcus (medial surface) posteriorly”
parietal lobe
What lobe is “the caudal-most cerebrum. In the medial view, is caudal to the parieto-occipital sulcus. In the lateral view, caudal to a line drawn from the parieto-occipital sulcus to the pre occipital notch
Occipital lobe
What lobe is “in the lateral view, defined caudally by an imaginary line from the parieto-occipital sulcus to the pre occipital notch. The superior boundary is the lateral sulcus extrapolated to the caudal border line
Temporal lobe
what lobe is “includes insular gyri located deep within the lateral sulcus, deep to the inferior frontal lobe and deep to the superior temporal lobe; gently separate the frontal and temporal lobes to view short and long insular gyri”
Limbic lobe
What is the function of the limbic lobe?
emotion, learning, and memory
most superior row of the frontal lobe, adjacent to longitudinal fissure
Superior frontal gyrus
below the superior frontal gyrus
Superior frontal sulcus
below the superior frontal sulcus
middle frontal gyrus
groove btw the middle and inferior gyri
inferior frontal sulcus
below the inferior frontal sulcus
inferior frontal gyrus
What are the 3 parts of the inferior frontal gyrus?
1) Pars opercularis
2) Pars triangularis
3) Pars orbitalis
What part of the inferior frontal gyrus is “posterior to the ascending branch, anterior to pre central sulcus”
Pars opercularis
What part of the inferior frontal gyrus is “between the ascending and anterior branch of the lateral sulcus”
pars triangularis
What part of the inferior frontal gyrus is “anterior to the anterior branch”
pars orbitalis
What parts of the inferior frontal gyrus make up Broca’s area?
Pars opercularis and Pars Triangularis
What is the function of Broca’s area?
Motor speech cortex
What gyrus is anterior to the central culcus
Precentral gyrus
What is the function of the pre central gyrus?
Primary motor cortex
What sulcus is “groove anterior to pre central gyrus”
Precentral sulcus
What gyrus is “posterior to central sulcus, anterior to post central sulcus”
Postcentral gyrus
What is the function of the post central gyrus?
Primary somatosensory cortex
What sulcus is “posterior to the post central gyrus”
Postcentral sulcus
What is “superior half of the parietal lobe, superior to the intraparietal sulcus”
Superior parietal lobule
separates inferior and superior parietal lobule; usually runs diagonally /c the posterior end closer to midline
Intraparietal sulcus
Lower half of the parietal lobe, inferior to the intraparietal sulcus; posterior portion is taller. Has 2 parts.
Inferior parietal lobule
Which part of the inferior parietal lobule “caps the posterior end of the lateral sulcus”
Supramarginal gyrus
What is the function of the supra marginal gyrus?
interrelate somesthetic, visual, and auditory stimuli
Which part of the inferior parietal lobule “caps the posterior end of the superior temporal sulcus”
Angular gyrus
What is the function of the angular gyrus?
comprehension of visual symbols and auditory sounds of language
a deep prominent groove on the medial surface, separating the occipital and parietal lobes; continues for a short distance on the super-lateral surface
Parieto-occipital sulcus
Forms the floor of the lateral sulcus. The “Transverse gyrus of Heschl” here extends deep into the lateral sulcus
Superior temporal gyrus
the groove btw the superior and middle temporal gyri
superior temporal sulcus
below the superior temporal suclus
middle temporal gyrus
the groove btw the middle and inferior temporal gyri
inferior temporal sulcus
below the inferior temporal sulcus
inferior temporal gyrus
lies deep in the lateral sulcus
Insula (island of Reil)
What is the function of the insula?
viscerosensory and visceromtor function
a massive group of transverse fibers connecting R and L hemispheres at bottom of longitudinal cerebral fissure
Corpus callosum
posterior portion, rather thick end of corpus callosum
splenium
What part of the corpus callosum is “main portion, runs horizontally btw selenium and genu”
body
What part of the corpus callosum is “the bend located in front and above the rostrum”
genu
anterior end of corpus callosum which tapers sharply downward toward terminal lamina
Rostrum
A round bundle of fibers transversely crossing the midline, located in the lamina terminals in the anterior wall of the third ventricle; connects amygdala to amygdala
anterior commissure
small fiber bundle traversing the midline inferior to the pineal gland and superior to the rostral limit of the cerebral aqueduct
posterior commissure
crossing of medial fibers of optic n. before joining optic tracts; best seen on inferior surface of brain
optic chiasm
thin anterior wall of the inferior portion of the 3rd ventricle, starts below rostrum of corpus callosum and extends down anteriorly to optic chaise. Most anterior part of hypothalamus
lamina terminalis
thin midline septum btw corpus callosum and fornix. Separates anterior horns of lateral ventricles
Septum pellucidum
connects the hippocampus to the hypothalamus; structurally includes the two columns, which form part of the inter ventricular foramena
Fornix
lies to R and L of 3rd ventricle, forming its lateral walls
Thalamus
What is the function of the thalamus?
important synaptic center of nearly all afferent and numerous efferent tracts
located on lamina of the tectum. Shaped like a pine cone, it is attached to the diencephalon by the pineal stalk, into which the 3rd ventricle extends as the pineal recess
Pineal gland
part of the diencephalon located beneath hypothalamic sulcus
hypothalamus
What’s the function of the hypothalamus?
mainly autonomic. some of its nuclei produce hormones that are transported to neurohypophysis and stored
the highly convoluted cortical structure located in the posterior cranial fossa, dorsal to the pons and medulla, and inferior to the posterior cerebral hemispheres
cerebellum
composed of cerebral peduncles, tegmentum, & tectum
midbrain (mesencephalon)
made up of the crus cerebri
cerebral peduncle
portion of brain dorsal to a plane thru cerebral aqueduct; it includes the superior and inferior colliculi
Tectum of midbrain
bridge btw interpeduncular fossa and pyramids. Consists of transverse fibers and cell groups
pons
inferior part of hindbrain. Begins at the striae medullar is of 4th ventricle and inferior margin of pons. Ends at the root fibers of 1st cervical nerve
medulla oblongata
a midline slit, extending from the lamina terminals rostrally to the cerebral aqueduct caudally, and from the body of the fornix superiorly to the inferior border of the hypothalamus inferiorly; receives CSF from the lateral ventricles via the IV foramena and delivers to the 4th ventricle via the cerebral aqueduct
3rd ventricle
CSF port btw each lateral ventricle and the common 3rd ventricle; formed in part by the columns of the fornix
Interventricular foramen
Paired ventricles normally spanning the frontal, parietal, occipital and temporal lobes; composed of an anterior horn, posterior horn, inferior horn, and trigone. Communicates /c 3rd ventricle via IV foramena
Lateral ventricles
narrow canal btw 3rd and 4th ventricles
Cerebral aqueduct (of Sylvius)
an largement of embryonal neural tube in the region of the rhombencephalon (pons and medulla)
4th ventricle
btw corpus callosum and the cingulate gyrus
Callosal sulcus (corpus callosum sulcus)
gyrus parallel to the corpus callosum btw cingulate and callosal sulci
Cingulate gyrus
immediately dorsal to the cingulate gyrus
cingulate sulcus
medially incomplete. however, frontal and parietal lobes on the medial surface can be distinguished by extending an imaginary line from the central sulcus at its superior limit over to the medial surface and perpendicular down to the cingulate gyrus
Central sulcus (Rolando’s Fissure)
What is the function of the paracentral lobule?
controls movement and sensation of the lower extremity
What brackets the imaginary central sulcus extended onto the medial surface. Can also be located by placing 2 finger tips against the medial cortex rostral to the marginal sulcus, the superiorly directed extension of the cingulate sulcus. The caudal finger tip overlies the parietal portion of the paracentral lobule (sensory) and the rostral finger tip overlies the frontal lobe portion (motor)
Paracentral lobule
Medial surface located anterior to the Parieto-occipital sulcus and posterior to the paracentral lobule. Continuous /c the superior parietal lobule on the lateral surface
Precuneus
Deep groove separating the occipital and parietal lobes on the medial surface
Parieto-occipital sulcus
upper half of medial occipital lobe, posterior to the parieto-occipital sulcus
Cuneus
deep groove appearing caudal and approximately perpendicular to the parieto-occipital sulcus. Bordered superiorly but eh cuneus, specially the cuneate gyrus, and inferiorly by the lingual gyrus.
Calcimine sulcus
what is the function of the medial occipital lobe?
Primary visual cortex
the lower half of the medial occipital lobe, inferior to the calcimine sulcus
lingual gyrus
most medial, inferior part of the temporal lobe bounded laterally by the collateral sulci
parahippocampal gyrus
the medial-most projection (bump) of the parahippocampal gyrus at its rostral end
uncus
lateral to the parahippocampal gyrus, medial to the medial occipitotemproal gyri. Extends into the occipital lobe
Collateral sulcus
Lateral and posterior to the collateral sulcus; continuous /c the inferior temporal gyrus on the lateral surface of the hemisphere and occipital gyri on the inferior surface of the occipital lobe
Occipitotemporal gyri
elongated gyrus above medial margin of orbit, btw longitudinal fissure and olfactory sulcus
Straight gyrus (gyrus rectus)
enlargement at the rostral tip of the olfactory tract
olfactory bulb
connection btw olfactory bulb and olfactory trigone on inferior surface of frontal lobe
olfactory tract
gyri of frontal lobe lateral to straight gyrus on inferior surface of frontal lobe
orbital gyri
only CN (II) that is CNS; exits medially from posterior pole of eye and extends to optic chiasm; fibers passing caudal from he chiasm do so as the optic tract
Optic nerve
crossing of 50% of the optic nerves to the contralateral side before joining optic tracts
Optic chiasm
the visual projection pathways btw optic chiasm and thalamic relay
optic tract
funnel-shaped stalk to the hypophysis btw tuber cinereum and optic chiasm
Infundibulum
prominent, rounded pair of eminences in floor of diencephalon, just caudal to optic chiasm; connected /c thalamus and hippocampus memory circuit
mammillary bodies
medial most gyrus of the inferior temporal lobe; bounded by collateral sulcus
Parahippocampal gyrus
What is the function of the parahippocampal gyrus?
learning and memory
posterior end of occipital lobe
occipital pole
located posterior to 4th ventricle, inferior to occipital lobe
cerebellum
obscured by the cephalic flexure and deep penetrating beaches of the posterior cerebral artery; when exposed midbrain structures visible from the ventral surface include the cerebral peduncles, interpeduncular fossa, posterior perforated substance and 3rd cranial nerve roots
midbrain
middle level of brainstem rostral to medulla and caudal to midbrain. Consists of longitudinal and transverse fibers and cranial nerve nuclei
Pons
caudal most level of brainstem; derives from myelencephalon; hindbrain. Posteriorly runs from stria medullaris of the 4th ventricle to C1 nerve root
Medulla oblongata
touch fibrous layer separated from wall of vertebral canal by epidural space
spinal dura mater
touch fibrous layer providing a protective capsule for brain; bound tightly to the inner surface of the skull
Cranial dura mater
Thin, translucent, nonvascular membrane attached to inner surface of the dura; arachnoid spans sulci but does not follow them
arachnoid
btw arachnoid and pia; filled /c CSF and arachnoid trabecular, which are connective tissue extensions form the arachnoid, and blood vessels that have exited or will penetrate brain tissue
subarachnoid space
soft, vascular layer attached closely to the entire surface of brain and spinal cord, dipping into all brain sulci
Pia mater
Sickle-shaped leaf of dura projecting into longitudinal cerebral fissure
Fall of cerebrum
Dural sheet btw ridge of the petrosal bone and transverse sinus; above cerebellum and separates it form occipital bone
Tentorium of cerebellum
located on midline along the superior edge of fall of cerebrum. Ends posteriorly at the confluence of sinuses
Superior sagittal sinus
small midline venous channel in free margin (inferior edge) of fall of cerebrum. Terminates in straight sinus
Inferior sagittal sinus
Protrusions of the arachnoid which project into the principal venous sinuses. CSF enters the venous circulation thru the villi
Arachnoid villus
Single, midline venous sinus; funs along the intersection of fall cerebrum and tentorium of cerebellum to end at the confluence of sinuses
Straight sinus
What 2 things join at the straight sinus?
(1) great cerebral vein
(2) inferior sagittal sinus
paired; originate from each side of the confluence of the sinuses and continues laterally and anteriorly into sigmoid sinus
transverse sinus
junction of superior sagittal, straight, and occipital sinuses at internal occipital protuberance.
confluence of sinuses
Where does the confluence of sinuses empty?
into the transverse sinus
continuous /c the transverse sinus. Leaves the lateral skull wall and extends in an S-curve to the jugular foramen to terminate as the jugular vein
sigmoid sinus
paired, spongy venous network on both sides of the sphenoid bone, into which the ophthalmic veins open
cavernous sinus
principle vein of the neck extending form the jugular foramen down tot he subclavian vein
internal jugular vein
enlargement of the subarachnoid space btw cerebellum and medulla, /c an opening to the 4th ventricle via median aperture
Cisterna magna (cerebellomedullar cistern)
subarachnoid space around the anterior surface of the pons and medulla continuous posteriorly /c cisterna magna
pontine cistern
subarachnoid space btw the cerebral peduncles, superior to the pons; contains the arterial circle of willis
interpeduncular cistern
subarachnoid space dorsal to midbrain, superior to the cerebellar root
Superior cistern
Are the lateral ventricles paired or unpaired?
paired
What part of the lateral ventricle is “anterior to the interventricular foramen, in the frontal lobe. boundaries consist of the septum pellucidum medially, head of caudate nucleus laterally, the body of the corpus callosum superiorly, and the menu of the corpus callosum anteriorly.”
Anterior horn
What part of the lateral ventricle is “central part, in the parietal lobe. The thalamus forms the floor and the corpus callosum forms the roof. The lateral wall is the body of the caudate nucleus; medial wall is the septum pellucidum. Contains part of the choroid plexus.”
Body
What part of the lateral ventricle is “small extension into the occipital lobe”
posterior horn
What part of the lateral ventricle is “extends down into the temporal lobe. The hippocampus forms most of the floor and medial wall. The tail of the caudate nucleus forms the roof. contains part of choroid plexus”
inferior horn
the connection of each lateral ventricle into the anterior part of the third ventricle
interventricular foramen (of Monroe)
midline, occupies most of the diencephalon. Anterior boundary is the terminal lamina and it extends back to the beginning of the cerebral aqueduct. The thalamus and hypothalamus form most of the wall of the ventricle. Part of the hypothalamus forms the floor. Contains choroid plexus
Third ventricle
a narrow canal btw 3rd and 4th ventricles in the midbrain and upper pons
Cerebral aqueduct (of Sylvius)
Enlargement of embryonal neural tube in region of rhombencephalon. Floor is rhomboid fossa, /c pons and rostral medulla anteriorly and the cerebellum posteriorly. Extends form the cerebral aqueduct rostrally to the central canal caudally. Contains choroid plexus
4th ventricle
paired lateral openings at the end of the R and L lateral recesses for passage of CSF out of the 4th ventricle into the cisterna magna
Lateral apertures (foramen of Luschka)
the midline terminus of the 4th ventricle allows CSF to leave 4th ventricle into the cisterna magna
Medial aperture (foramen of Magendie)
Vascular membranous material secretes most of the CSF /c typical locations in each ventricle
Choroid plexus
Where is choroid plexus in the lateral ventricle?
in the floor of each lateral ventricle, extending form near the tip of the inferior horn, around in C-shaped course through the ventricle body to the IV foramen (not in anterior or posterior horns). Makes up largest mass of choroid plexus
Where is choroid plexus in the 3rd ventricle?
hanging from the thin roof of the 3rd ventricle continuous anteriorly via IV Forman /c choroid plexuses of lateral ventricles
Where is choroid plexus in the 4th ventricle?
in the roof of the medulla, extending into the lateral apertures
Runs un-branched from bifurcation of the common carotid a. up to base of skull, continuing through carotid canal to its terminal division into middle and anterior cerebral arteries
Internal carotid a.
Paired connections btw internal carotid a. and posterior cerebral a.; form anastomosis btw anterior and posterior circulation; highly variable
posterior communicating a.
one of the 2 terminal branches of the internal carotid a.; runs posteriorly above corpus callosum to supply the major portion of the medial brain surface and the superior gyri of the lateral surface of the hemisphere
anterior cerebral a.
unpaired connection btw R and L anterior cerebral a.
anterior communicating a.
the other terminal branch of the internal carotid a. passes laterally to enter the lateral sulcus, supplying the lateral aspects of the frontal, parietal, occipital and temporal lobes
Middle cerebral a.
unpaired, thick arterial stem originating as the union of the R and L vertebral arteries and terminating as the paired posterior cerebral arteries
Basilar a.
formed by the bifurcation of the basilar a.; courses lateral to the cerebral peduncles to supply the medial and inferior surfaces of the occipital and temporal lobes, the rostral midbrain and caudal cerebrum
Posterior cerebral a.
arterial circle at base of brain; often asymmetric; common site of aneurysms
Circle of Willis
What arteries make up the circle of Willis?
- posterior cerebral a. (paired)
- posterior communicating a. (paired)
- internal carotid a. (paired)
- anterior cerebral a. (paired)
- anterior communicating a. (unpaired)
paired arteries run rostrally along the medulla and fuse at the junction btw the medulla and pons to form the basilar a.
Vertebral a.
arises from the basilar a., just before its bifurcation, winds around cerebral peduncles and supplies the superior surface of the cerebellum and much of the caudal midbrain and rostral pons
Superior cerebellar a.
a first major branch of the basilar a. rostral to the fusion point of the vertebral arteries; supplies anterior portions of the inferior surface of the cerebellum and parts of the caudal pons and upper medulla, notably the cochlear nuclei
Anterior inferior cerebellar a.
Paired branches coming off the vertebral arteries, laterally, just caudal to their fusion to form the basilar al; curves dorsally around the brainstem and supply the posterior portions of the inferior surface of the cerebellum and much of the lateral medulla; characteristic looping across cerebellar surface
Posterior inferior cerebellar a.
small midline artery running along anterior median fissure of spinal cord, formed by two contributory branches extending medially from the medial aspect of the vertebral arteries just caudal to their fusion to form the basilar a.
anterior spinal a.
separated from wall of vertebral canal by epidural space
spinal dura mater
thin, nonvascular membrane attached to spinal dura only through surface tension, with connective tissue fibers to pia
spinal arachnoid
between arachnoid and pia, filled with arachnoid trabeculae and cerebrospinal fluid.
subarachnoid space
vascular connective tissue membrane firmly attached to surface of cord
spinal pia mater
the spinal cord is suspended in the dural sheath by this pia-derived ligament on each side. In the form of a ribbon, attached along the lateral surface of the cord midway between the dorsal and ventral roots. Lateral edges are serrated.
denticulate ligaments
posterior, sensory root.
dorsal roots
midline sulcus along dorsal surface of spinal cord
dorsal median sulcus
paramedian sulcus along dorsal surface of spinal cord, separating fasciculus cuneatus from fasciculus gracilis
dorsal intermediate sulci
along the dorsolateral surface of spinal cord, from which the dorsal rootlets emerge
dorsolateral sulcus
paired arteries on the posterior surface of the spinal cord, running along line where the dorsal rootlets exit
posterior spinal artery
anterior, motor root.
ventral roots
unpaired small artery in front of anterior median fissure of spinal cord.
anterior spinal artery
deep groove on anterior side of cord
ventral median fissure (anterior median fissure)
tapered end of spinal cord that continues into filum terminale at the vertebral level of L1 or L2
conus medullaris
thin terminal non-neural filament of spinal cord attached below to posterior surface of coccyx.
filum terminale
all spinal nerve roots extending caudally from L1 or L2, including filum terminale.
cauda equina
from C4 to T1; most of the corresponding spinal nerves form the brachial plexuses for innervation of the upper extremities
cervical enlargement
from L2 to S3; Lumbosacral plexuses for innervation of the lower extremities.
lumbosacral enlargement
elongated nucleus surrounding the thalamus
caudate nucleus
What part of the caudate nucleus is “located anteriorly; forms the lateral wall of anterior horn of lateral ventricle; medial to anterior limb of the internal capsule”
head
What part of the caudate nucleus is “middle part of caudate nucleus, superior to the thalamus and the internal capsule.”
body
What part of the caudate nucleus is “tapering posterior part that accompanies inferior horn (lateral to lateral ventricle, superolateral to the inferior horn of the lateral ventricle. Very difficult to see.”
Tail
lateral portion of lentiform nucleus.
putamen
medial portion of lentiform nucleus, may have several parts
globus pallidus
pair of almond-shaped nuclei proximal to the posterior limb of the internal capsule in the posterior thalamus; stroke lesions here cause a characteristic flailing motion usually affecting one side (hemiballismus).
subthalamic nucleus
darkly pigmented nucleus between crus cerebri and tegmentum of midbrain
substantia nigra
unpaired midline of cerebellum approximately 1.5 cm in width
vermis
paired, on either side of the vermis.
cerebellar hemispheres
deep fissure between anterior lobe and posterior lobe.
primary fissure
part of the superior surface rostral to the primary fissure.
anterior lobe
part of the cerebellum caudal to the primary fissure on both superior and inferior surface.
posterior lobe
median elevation of the inferior vermis (as it curves rostrally) connected with flocculus; can see only in prosection or half-brain
nodulus
paired structures lateral to the cerebellopontine angle visible on the anterior surface of the cerebellum; functionally connected to the single midline nodulus.
flocculus(i)
consists of paired flocculi and the medial nodule.
flocculonodular lobe
connection of cerebellum with the brain stem:
cerebellar peduncles
most prominent of the 4 deep cerebellar nuclei (fastigial, globose, embolliform, dentate) located within each cerebellar hemisphere
dentate nucleus of cerebellum
What is the function of the dentate nucleus of the cerebellum?
mediates finely articulated, learned movements of digits and motor learning
What is the function of the interposed (emboliform & globose) nuclei?
mediate coordinated ongoing movements of proximal limbs
What is the function of the fastigial nucleus?
mediates coordinated axial posture and gaze (midline structures)
composed of crus cerebri (cerebral peduncles), tegmentum and tectum.
midbrain
bulbous structure, the basis pontis, is the bridge between interpeduncular fossa and medullary pyramids through which longitudinal and transverse fibers pass; bordered by well defined pontomesencephalic and pontomedullary junctions. Posterior to the basis pontis is a tegmentum, which houses cranial nerve nuclei and forms a portion of the rhomboid fossa, a depression of the 4th ventricle.
pons (metencephalon)
Extends caudally from the striae medullaris of fourth ventricle posteriorly to C1 nerve root. Anteriorly, caudal from ponto medullary junction to C1 nerve root. Contains a tegmentum for housing cranial nerve nuclei, also adjacent to the 4th ventricle, and more anteriorly situation long tracts, e.g. the pyramids.
medulla oblongata (myelencephalon)-
paired stalks emerging from internal capsule to form the ventrolateral midbrain; disappear at superior margin of pons
crus cerebri (cerebral peduncle)
What is the function of the crus cerebri (cerebral peduncles)?
Carry descending motor tracts
roof of the cerebral aqueduct
tectum
posterior to interpeduncular fossa, anterior to cerebral aqueduct; houses midbrain cranial nerve nuclei
tegmentum
the inferior pair of rounded elevations on the dorsal surface of the midbrain
inferior colliculus
What is the function of the inferior colliculus?
A relay structure for the auditory pathway
the superior pair of rounded elevations on the dorsal surface of the midbrain tectum;
superior colliculus
What is the function of the superior colliculus?
a relay structure for the visual pathway
large paired nerves exiting from the interpeduncular fossa (midbrain). Nuclei located in midbrain tegmentum
oculomotor nerve (CN III)
emerges dorsocaudally from midbrain tectum immediately caudal to the inferior colliculus; courses ventrally to be found in vicinity of oculomotor nerve.
trochlear nerve (CN IV)
space between the two crus cerebri of the midbrain
interpeduncular fossa
superior, paired stalks of fibers exiting cerebellum into midbrain
superior cerebellar peduncle
emerges ventrally from pontomedullary junction, lateral to the midline basilar sulcus (where basilar artery runs)
abducens nerve (CN VI)
What CN “emerges ventrally from the pons, lateral to the abduncens nerve, in the cerebellopontine angle”
facial nerve (CN VII)
What CN “emerges immediately lateral to facial nerve”
vestibulocochlear nerve (CN VIII)
formed by anterior margin of the 4th ventricle
rhomboid fossa
posterior portion of pons containing cranial nerve nuclei and adjacent to 4th ventricle
tegmentum
largest and middle of three stalks of fibers connecting cerebellum to brainstem
middle cerebellar peduncle –
What is the function of the middle cerebellar peduncle?
relays fibers projecting from motor cortex via pons to cerebellum (corticopontocerebellar fibers).
emerges laterally from the pons midway between pontomesencephalic and pontomedullary junctions; includes large sensory and small motor portions
trigeminal nerve (CN V)
paired along anterior surface of the medulla; elevated by underlying corticospinal tracts; separated by anterior median fissure. Inferior margin is the pyramidal decussation above C1 nerve root
pyramids
exits from ventrolateral medulla between pyramid and olive via numerous roots emanating from preolivary sulcus and passes through hypoglossal canal.
hypoglossal nerve (CN XII)
lateral to each pyramid; marks the position of the inferior olivary nucleus. Rootlets of the glossopharyngeal, vagus, and accessory nerves are attached to the lateral area just dorsal to the olive. Hypoglossal nerve emerges ventral to the olive.
olive
emerges ventrolaterally from medulla in postolivary sulcus
glossopharyngeal nerve (CN IX)
very broad nerve that emerges from posterior lateral sulcus with CN IX and passes through the jugular foramen
vagus nerve (CN X)
emerges from brain in postolivary sulcus, just caudal to the vagus n.; unites temporarily with the spinal roots and exit via jugular foramen with cranial nerves IX and X.
accessory nerve (CN XI)
para-midline bumps located on dorsal surface of caudal medulla; marks the position of the nucleus gracilis (synaptic target of the fasciculus gracilis).
gracile tubercle-
para-midline bumps located on dorsal surface of caudal medulla, lateral to the gracile tubercles; marks the position of the nucleus cuneatus (synaptic target of the fasciculus cuneatus).
cuneate tubercle-
floor of the fourth ventricle:
rhomboid fossa
the largest pair of bumps of the rhomboid fossa, on either side of the median sulcus, marks the point where facial nerve fibers posterior to the abducens nucleus
facial colliculus
region just medial to the lateral recess in the rhomboid fossa, lateral to sulcus limitans; represents the location of the vestibular nuclei
vestibular area
small transverse connection at lower end of rhomboid fossa; also is the upper end of posterior median sulcus of medulla.
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