1: Topographic Anatomy of the Brain and Spinal Cord Flashcards
Contains surface images for identification of parts and details about all parts covered in topographic anatomy lecture and lab
Spinal cord enlargements: where are they, and why are they present?
Enlargements are at cervical and lumbar segments
Cervical contain nerves supplying the arms, lumbar the legs
Conus medullaris
The lowest tapering portion of the spinal cord
Filum terminale interna
The continuation of the pia mater from the end of the conus medullaris
Cauda equina
The lumbar and sacral nerve roots arising from the conus medullaris
What are the dorsolateral and ventrolateral sulci?
Small grooves on the dorsolateral and ventrolateral portions of the spinal cord
Located at the point of exit of the nerve roots
Briefly describe the anterior median sulcus, dorsal median sulus, and dorsal intermediate sulcus
All help divide the spinal cord into three basic divisions (dorsal, lateral, and ventral funiculi)
AMS: anterior spinal artery runs here
DMS: very small sulcus
DIS: between the DMS and dorsolateral sulcus, a sulcus only present in the upper part of the spinal cord because it separates the fibers from the legs (medial) from those of the arms (lateral)
Dorsal funiculus: where is it and what is it?
Between dorsal median sulcus and dorsolateral sulcus
Almost exclusively contains the dorsal columns: ascending tract that conveys vibratory sense, well-localized touch, and joint position sense
Lateral funiculus: where is it and (brief) what does it do?
Between dorsolateral and ventrolateral sulci
Contains contralateral corticospinal and spinothalamic tracts
Damage -> weakness
Ventral funiculus: where is it?
Between ventrolateral and anterior median sulci
Distinguish the ventral horn from the dorsal horn
Ventral horn protrudes forward, dorsal protrudes back
Ventral is motor, dorsal is sensory
Briefly, what is the substantia gelatinosa?
A term for the most posterior portion of the dorsal horn
What is this structure?
Pons
What is this structure?
What does it do?
What emanates from it?
What is the effect of damage to this structure?
Middle cerebellar peduncle
Large white matter tract connecting the basal pons to cerebellum
The trigeminal nerve emerges from the junction of the basal pons with the middle cerebellar peduncle.
Incoordination (cerebellum functions to coordinate skilled movements)
Where is the medulla?
Portion of the brainstem from the spinal cord to the pons
What is the midbrain?
The portion of the brainstem extending rostally form the pons
What is this structure?
What does it contain?
Inferior olive (inferior olivary nucleus)
Contains a motor nucleus connected to the contralateral cerebellum
What is the post olivary sulcus and what does it contain?
What is the preolivary sulcus and what does it contain?
Post.: groove located dorsal to the protuberance of the inferior olive; CN IX and CN X nerve filaments emerge from here
**Pre.: **groove located ventral to protuberance of the inferior olive; CN XII filaments emerge from here
What is this structure?
What does it contain?
Brief description of purpose
Medullary pyramids
Bundles of fibers from cerebral cortex extending down to spinal cord (corticospinal neurons)
Critically important for voluntary movements (especially skilled)
What is this structure?
What does it contain?
Pyramidal decussation (crossing of fibers)
Comprise the descending motor tract in the lateral funiculus of the cord
What is this structure?
What is its function?
CN VI - Abducens nerve
Lateral eye movement
What is this structure?
What is its function?
CN VII - Facial nerve
Movement of muscles of facial expression
What is this structure?
What is its function?
CN VIII - Vestibulocochlear nerve
Hearing and inner ear balance
What is the acoustic tubercle?
Portions of CN VIII that wrap around the inferior cerebellar peduncle
What is this structure?
What is its function?
CN V - Trigeminal Nerve
Facial sensations and jaw movements
What is this structure?
What is its function?
Cerebral peduncle (crus cerebri): prominent bands of fibers on either side of the interpeduncular fossa (peduncle means “stalk”)
The primary fiber bundles that connect the cerebral cortex to the brainstem.
Allows the cortex to control the contralateral side of the body and head
What is this structure?
What is its function?
From where is it emanating?
CN III - Oculomotor nerve
Opening the eye, controlling many eye muscles, constricting the pupil
Found in the interpeduncular fossa: the depression in between the cerebral peduncle; contains the posterior perforated substance where branches of the basilar artery enter the midbrain
Name this structure.
Optic chiasm: location where the right and left optic nerves meet and form the optic tracts
Name this structure.
Olfactory tract
Name this structure.
Optic tract
Name this structure.
Pituitary stalk (infundibulum): part of the hypothalamus that is funnel-shaped; at the narrow part of the funnel is the stalk of the pituitary gland.
Name this structure.
Mamillary bodies: prominences on the ventral side of the hypothalamus that are part of the limbic system
Demarcate the junction between the midbrain and diencephalon
Name this structure.
Cerebellar flocculus: the small piece of cerebellum that lies in the area between the ventral pons and cerebellum
Flocculus = “a small tuft or mass”
Part of the flocculonodular lobe
Name this structure.
Cerebellar hemisphere: one of the two lateral portions of the cerebellum, separated by the vermis
Name this structure.
Cerebellar tonsil: the most inferior part of the cerebellum that lies just superior to the foramen magnum
Fill in the following structures related to the cerebellum:
The majority of the cerebellum consists of small folds, called ________
A deep division (___________) separates the anterior lobe of the cerebellum from the posterior.
There are two easily identified divisions to the cerebellum. The __________ is in the midline, while the lateral portions are termed the __________.
There are also two small lobes that are situated between the cerebellum and medulla, the ________ laterally and the _________ in the midline.
The majority of the cerebellum consists of small folds, called folia.
A deep division (primary fissure) separates the anterior lobe of the cerebellum from the posterior.
There are two easily identified divisions to the cerebellum. The vermis is in the midline, while the lateral portions are termed the hemispheres.
There are also two small lobes that are situated between the cerebellum and medulla, the flocculus laterally and the nodulus in the midline.
What is this structure?
Inferior cerebellar peduncle (aka restifom body): white matter tract connecting the medulla to the cerebellum
Forms part of the wall of the 4th ventricle
What is this structure?
Superior cerebellar peduncle (aka brachium conjunctivum): white matter tract connecting the midbrain to the cerebellum
What is this structure? What is it separating?
4th ventricle
Separates cerebellum from dorsal brain stem
Fill in the blank:
CSF leaves the fourth ventricle to the subarachnoid space through openings caudal to the cerebellum, the lateral __________________ and the midline ______________________
Lateral foramina of Luschka
Midline foramen of Magendie
What is the obex?
The caudal-most point of the 4th ventricle
What is this structure?
Gracile tubercle: prominence immediately lateral to the midline over the gracile nucleus
Continuous with the fasciculus gracilis inferiorly
What is this structure?
Cuneate tubercle: prominence lateral to the gracile tubercle over the cuneate nucleus
Continuous with the fasciculus cuneatus inferiorly
What is this structure?
Facial colliculus: prominence over the facial nerve as it does its “U-turn” around the abducens nucleus inside the pons
What is this structure?
Vestribular trigone: area lateral to the sulcus limitans that marks the position of the underlying vestibular nuclei
What is this structure?
Sulcus limitans: vertical groove on either side of the median sulcus
Marks the embryologic division between the alar and basal plates, which in the adult, separates motor and sensory nuclei (the motor nuclei are medial to the sulcus, sensory lateral).
Define corpora quadrigemina.
The four bumps on the dorsal surface of the midbrain (two inferior colliculi, two superior colliculi)
What is this structure?
What is its function?
Inferior colliculus: the “midbrain auditory center”; receives just about all the information from the cochlear nuclei (some directly and some indirectly) and integrates it
Neurons from the inferior colliculus project to the medial geniculate body, which is the thalamic relay for auditory information
What is this structure?
What is its function?
Superior colliculus: receives information directly from the retina (first-order neurons in the optic tract project to superior colliculus as well as other locations)
Involved in coordinating movements of the head and eyes
What are the brachium of the inferior colliculi and brachium of the superior colliculi?
Small ridges running laterally from the inferior/superior colliculi, respectively, on the lateral side of the midbrain
Superior: connects the superior colliculus to the lateral geniculate body; it passes superior to the medial geniculate body in its course
**Inferior: **conveys neurons from the inferior colliculus to the medial geniculate body
What is this structure?
Hypoglossal trigone: prominence over the hypoglossal nucleus (near the midline)
What is this structure?
Vagal trigone: prominence over the dorsal motor nucleus of CN X located immediately lateral to the hypoglossal trigone
The dorsal motor nucleus contains cell bodies of preganglionic parasympathetic neurons.
What is this structure?
CN XI - Accessory nerve
What is this structure?
Cerebral peduncle
What is this structure?
Dorsal median sulcus
What is this structure?
CN VII - Facial nerve
What is this structure?
Fasiculus cuneatus
What is this structure?
Fasiculus gracilis
What is this structure?
CN XII - Hypoglossal nerve
What is this structure?
Lateral funiculus
What is this structure?
Middle cerebellar peduncle
What is this structure?
CN V - Trigeminal nerve
What is this structure?
CN IV - Trochlear nerve
What are these structures?
CN X - Vagus and CN IX - glossopharyngeal nerves
What is this structure?
CN VIII - Vestibulocochlear nerve
What is this structure? What is its function?
Thalamus: a large nuclear mass, a site of relay of many of the inputs to and from the cerebral cortex
Most of the information (sensory and motor feedback information) that is required by the cerebral cortex passes through the thalamus
Makes up the bulk of the lateral walls of the third ventricle
What is this structure?
What is its function?
Hypothalamus: involved in endocrine regulation, regulation of feeding, autonomic regulation, regulation of sexual behaviors, thermoregulation, and fluid/electrolyte homeostasis
What is the lamina terminalis?
On the rostral side of the infundibulum
The most rostral portion of the embyologic nervous system, where the anterior neuropore closed
Forms the rostral border of the hypothalamus
What is this structure?
Pineal gland (makes up most of the epithalamus): part of the diencephalon that is located rostral to the superior colliculi
Produces melatonin (associated with circadian rhythms) as well as other hormones that seem to influence gonadal development.
What are the habenular nuclei?
Tiny swellings anterior to the pineal gland
Thought to be involved in integration of olfactory, sensory and visceral information
What is this structure?
What is its function?
Medial geniculate nucleus
Chief site of relay of auditory information from the inferior colliculus (via the brachium of the inferior colliculus) to the cerebral cortex
What is this structure?
What is its function?
Lateral geniculate nucleus
Receives information from the superior colliculus related to head/eye coordination
What is this structure?
Anterior commisure: a tract that connects the two temporal lobes found at the dorsal (superior) aspect of the lamina terminalis.
What is this structure?
Rostrum of corpus callosum
What is this structure?
Thalamic adhesion
What is this structure?
Genu of corpus callosum
What is this structure?
Septum pellucidum: a thin membrane that separates the two lateral ventricles
What is this structure?
Interventricular foramen (of Monroe): an opening inferior to the fornix by which spinal fluid can pass from the lateral ventricle to the third ventricle
What is this structure?
Fornix: a thickening at the inferiormost portion of the septum pellucidum; a C-shaped tract that follows the lateral ventricle
Extends between the hippocampus and the hypothalamus
What is this structure?
Body of corpus callosum: a collection of fibers that connects the two cerebral hemispheres
What is this structure?
Choroid plexus: rough and irregular tissue extending through the foramen of Monroe into the lateral ventricle
Responsible for production of CSF
What is this structure?
Parieto-occipital sulcus: sulcus the separates the parietal and occipital lobes
What is this structure?
Splenium of corpus callosum
What is this structure?
Tectum: the “roof” or dorsal part of the midbrain containing the corpora quadrigemina
What is this structure?
Calcarine sulcus: sulcus within the occipital lobe that merges with the parieto-occipital sulcus
The gyri surrounding this sulcus are part of the visual cortex
What is this structure?
Primary fissure: the fissure that separates the anterior lobe of the cerebellum from the posterior lobe
Found on the part of the cerebellum that is covered by the overlying cerebral hemispheres, thus it is best seen in a midsagittal view
What is this structure?
Vermis: midline portion of the cerebellum that gets it name from the fact that it resembles a worm
Functionally part of the spinocerebellum
What is this structure?
Pons
What is this structure?
Medulla
What is this structure?
Cingulate gyrus: the C-shaped gyrus that follows the dorsal aspect of the corpus callosum
What is this structure?
Optic chiasm
What is this structure?
Pituitary gland: an endocrine gland that is suspended from the hypothalamus, but is not technically part of it
What is the hypothalamic sulcus?
The hypothalamic sulcus is a groove in lateral wall of third ventricle, marking the boundary between the thalamus and hypothalamus
What is the stria medullaris thalami?
A ridge running from anterior to posterior along the wall of the third ventricle
Contains afferent neurons traveling from the amygdala to the habenula
Meets the habenula at its posterior end
What is this structure?
Lateral (Sylvian) fissure: fissure on the lateral aspect of the cerebrum that separates the temporal lobe from the frontal/parietal lobes
When the lateral fissure is opened, the insula can be seen.
What is this structure?
Central sulcus: sulcus in the coronal plane that separates the frontal and parietal lobes
What is this structure?
Occipital lobe
What is this structure?
Frontal lobe
What structure is this?
Temporal lobe
What is this structure?
Parietal lobe
What is this structure?
Precentral gyrus (primary motor cortex): controls movement of face and extremities
What is this structure?
Postcentral gyrus (primary somatosensory cortex): termination of many somatic sensory fibers coming from thalamus
What is this structure?
Transverse gyri (of Heschl): primary auditory cortex
Run into the lateral fissure on the dorsal aspect of the temporal lobe
What is this structure?
Insula (aka isle of Reil): group of small gyri located within the lateral fissure
Associated with visceral functions.
What is this structure?
What is its function?
Premotor cortex: planning and initiating movement
What is this structure?
What is its function?
Dorsolateral prefrontal cortex: executive functions such as working memory, planning, problem solving, reasoning and organizing
What is this structure?
What is its function?
Orbitomedial prefrontal cortex: impulse control, personality, reactivity to the surroundings and mood
What is this structure?
What is its function?
Broca’s area: the motor language area
What is this structure?
What is its function?
Somatosensory association cortex: interpret what a somatic sensory signal is
Where are the areas that are involved in attention and visuospatial function (knowing how things can go together and where things are in relation to one another)?
In the posterior parts of the parietal lobes
What is this structure?
What is its function?
Auditory association area: involved in interpreting sound
What is this structure?
What is its function?
Wernicke’s area: involved in interpreting language
What is this structure?
What is its function?
Parahippocampal gyrus: along with hippocampus, critical for short-term memory (minutes to hours)
the most medial gyrus on the ventral aspect of the temporal lobe
What is this structure? Why is it there?
Uncus: a medial swelling on the rostral end of the parahippocampal gyrus
Present because the amygdala is deep to the cortex in its location (amygdala is responsible for emotional learning, particularly responses to fear and anxiety)
What is this structure?
What is its function?
Visual association area: involved in interpreting aspects of what you are seeing
What is the caudate nucleus?
Where is it located?
What is its function?
A large ridge running posterior to anterior, paralleling the lateral ventricle
Location: lateral to the thalamus in the floor of the lateral ventricle
Function: part of the basal ganglia, mostly involved in regulating motor function and cerebral cortical excitability
What is the stria terminalis?
What is its function?
A thin band in the groove between the thalamus and caudate nucleus
What is this structure?
Primary visual cortex
What is this structure?
What is its function?
Primary auditory cortex (on the transverse gyri [of Heschl])
Dura mater
falx cerebri
Fold of dura that extends between the cerebral hemispheres
Occupies the longitudinal fissure
Contains the superior sagittal sinus in its superior edge, inferior sagittal sinus in its inferior edge, and the straight sinus at its junction with the tentorium cerebelli.
tentorium cerebelli
horizontal fold of dura between the cerebral hemispheres and cerebellum; contains the transverse sinus in its lateral edge, and the superior petrosal sinus where it meets the petrous ridge.
falx cerebelli
small fold of dura between the two halves of the cerebellum (stops at vermis); contains the occipital sinus.
arachnoid mater
the middle layer of connective tissue that surrounds the brain; its consistency resembles a spider web, although it is water-tight.
pia mater
innermost layer of connective tissue surrounding the brain; it is firmly attached to the surface of the brain and cannot be separated from it.
subarachnoid space
space between the arachnoid and pia mater that contains cerebrospinal fluid; large blood vessels of the brain travel within this space.
vertebral artery
one of the two sources of arterial blood to the brain
arises from the subclavian artery, travels superiorly in the neck and enters the cranial cavity through the foramen magnum
the right and left vertebral arteries merge to form the basilar artery
Important branches to remember are the posterior inferior cerebellar artery (PICA), and the anterior and posterior spinal arteries.
basilar artery
artery that travels on the ventral surface of the pons
several important branches of the basilar are the anterior inferior cerebellar artery (AICA) and superior cerebellar
terminates by dividing into the two posterior cerebral arteries
posterior perforated substance
area in the interpeduncular fossa penetrated by small vessels that arise from the terminal region of the basilar artery
internal carotid artery
the other source of arterial blood to the brain (besides the vertebral arteries)
arises from the common carotid artery in the neck and enters the cranial cavity through the carotid canal
gives off the posterior communicating and anterior choroidal arteries
terminates by dividing into the anterior cerebral (ACA) and middle cerebral (MCA) arteries.
anterior choroidal artery
arises from the internal carotid near where it bifurcates into anterior and middle cerebral
travels in a dorsal direction following the optic tract.
posterior communicating artery
branch of the internal carotid that connects to the posterior cerebral artery, thus helping to form the cerebral arterial circle.
anterior perforated substance
area lateral to the optic chiasm, punctured by small vessels that branch from the anterior and middle cerebral arteries and supply deep areas of the brain.
anterior communicating artery
small artery that connects the two anterior cerebral arteries
Define tegmentum.
a synonym for the ventral portion of the midbrain (i.e. the area ventral to the cerebral aqueduct)
Which cranial nerves emerge from the medullary-pontine junction?
Abducens nerve
Facial nerve
Vestibulocochlear nerve
tuber cinereum
area between the mammillary bodies and infundibulum; has a swelling called the median eminence
olfactory sulcus
the sulcus normally “covered” by the olfactory bulb/tract
separates the straight gyrus from the orbital frontal gyri
The olfactory tract ends by dividing into medial and lateral stria.
orbital frontal gyri
gyri on the lateral aspect of the olfactory sulcus
What is this structure?
Gyrus rectus (aka straight gyrus): gyrus on the medial aspect of the olfactory sulcus
collateral sulcus
sulcus on the lateral aspect of the parahippocampal gyrus that separates this gyrus from the remainder of the temporal lobe
posterolateral fissure
Sulcus between the flocculus and the posterior lobe of the cerebellum (specifically the tonsillar part of the posterior lobe)
Caudal to the flocculus
vellum
name for the membranous dorsal wall of the 4th ventricle
the area rostral to the core of the cerebellum is called the superior medullary vellum, while the area caudal to the core of the cerebellum is the inferior medullary vellum.
posterior commissure
marks the junction of the midbrain and diencephalon dorsally (not technically part of either area)
It is a white matter tract that contains axons involved in the pupillary light reflex
Commissure = a tract that crosses the midline
What is this structure?
Angular gyrus: one of the two gyri associated with the caudal part of the lateral fissure
What is this structure?
Supramarginal gyrus: one of the two gyri associated with the caudal part of the lateral fissure
subcallosal region
gyrus ventral to the rostrum of the corpus callosum.
pulvinar
the most posterior part of the thalamus that has the geniculate bodies on its surface
lateral ventricle
large C-shaped space in the brain that contains cerebrospinal fluid (CSF)
There are two lateral ventricles – one in each cerebral hemisphere
The floor of the lateral ventricle (ventral surface) is primarily in contact with the thalamus, while the lateral wall of the lateral ventricle is in contact with the caudate nucleus
striae medullares
Transverse fibers that separate the facial colliculus and hypoglossal trigone
These neurons are second order neurons in the auditory pathway, part of the posterior acoustic stria (a pathway that leads to the lateral lemniscus) that stays close to the surface
cerebral aqueduct (aqueduct of Sylvius)
narrow channel within the midbrain that connects the third and fourth ventricles
