Neuroanatomy Flashcards
Which bones make up the anterior cranial fossa?
frontal bone
ethmoid bone
lesser wing of sphenoid bone
Where does the ACF lie over?
superiorly over the nasal and orbital cavities
What does the ACF accommodate?
anteroinferior portions of the frontal lobes of the brain
Where is the crista galli (latin for cock’s comb)?
Midline of the ethmoid bone
Where is the cribriform plate?
Either side of the crista galli
What is the cribriform plate and what does it contain?
a sheet of bone seen either side of the crista galli which contains numerous small foramina
these transmit olfactory nerve fibres (CN I) into the nasal cavity
Also contains anterior and posterior ethmoidal foramen
What does the anterior ethmoidal foramen transmit?
transmits the anterior ethmoidal artery, nerve and vein
What does the posterior ethmoidal foramen do?
transmits the posterior ethmoidal artery, nerve and vein
The cribriform is the thinnest part of the ACF and is most likely to fracture. What are the 2 clinical consequences of this?
Anosmia
CSF rhinorrhoea
What forms the body of the middle cranial fossa?
the body and greater wing of the sphenoid
squamous and petrous parts of the temporal bone
What forms the central part of the middle cranial fossa?
the body of the sphenoid bone
What does the central part of the MCF contain and what is its role?
sella turcica
holds the pituitary gland
What are the 3 parts of the sella turcica?
- tuberculum sellae
- pituitary fossa
- dorsum sellae
What is the sella turcica surrounded by?
the anterior and posterior clinoid processes
What is the tentorium cerebelli and what is attached to?
a membranous sheet that divides the brain.
attached at clinoid processes
separates occipital and temporal cerebral hemisphere from the cerebellum and infratentorial brainstem
Where are optic canals (foramina) and what do they transmit?
situated anteriorly in the middle cranial fossa
transmit the optic nerves (CN II) and ophthalmic arteries into the orbital cavities
What 4 foramina are lateral to the central part of the middle cranial fossa?
superior orbital fissure
foramen rotundum
foramen ovale
foramen spinosum
Where does the superior orbital fissure open and what does it transmit?
opens anteriorly into the orbit
transmits the oculomotor nerve (CN III), trochlear nerve (CN IV), ophthalmic branch of the trigeminal nerve (CN V1), abducens nerve (CN VI), opthalmic veins and sympathetic fibres
Where does the foramen rotundum open and what does it transmit?
opens into the pterygopalatine fossa
transmits the maxillary branch of the trigeminal nerve (CN V2)
Where does the foramen ovale open and what does it transmit?
opens into the infratemporal fossa
transmits the mandibular branch of the trigeminal nerve (CN V3) and accessory meningeal artery
Where does the foramen spinosum open into and what does it transmit?
opens into the infratemporal fossa
transmits the middle meningeal artery, middle meningeal vein and a meningeal branch of CN V3
What does the carotid canal transmit and where is it?
located posteriorly and medially to the foramen ovale
Internal carotid artery
Deep petrosal nerve
What junction does the foramen lacerum mark and what is it filled with in life?
sphenoid, temporal and occipital bones
filled with cartilage, only pierced by small blood vessels
What bones make up the posterior cranial fossa?
the occipital bone and the two temporal bones
What does the posterior cranial fossa accommodate?
accommodates the brainstem and cerebellum
What is the internal acoustic meatus and where is it? (what does it transmit)
oval opening in the posterior aspect of petrous part of temporal bone
Transmits facial nerve (CN VII), vestibulocochlear nerve (CN VIII) and labyrinthine artery
What does the foramen magnum transmit and where is it?
lies centrally in the floor of the posterior cranial fossa
the largest foramen in the skull
transmits the medulla of the brain, meninges, vertebral arteries, spinal accessory nerve
What does the jugular foramina transmit and where are they?
situated either side of the foramen magnum
Each transmits the
- glossopharyngeal nerve, vagus nerve, spinal accessory nerve (descending)
- internal jugular vein
- inferior petrosal sinus, sigmoid sinus
- meningeal branches of the ascending pharyngeal and occipital arteries
Where is the hypoglossal canal and what does it transmit?
Immediately superior to the anterolateral margin of the foramen magnum
It transmits the hypoglossal nerve through the occipital bone
What divides the cerebellar fossae?
divided medially by a ridge of bone, the internal occipital crest
What is responsible for superior eyelid movement?
Levator palpebrae superioris
Where does the levator palpebrae superioris attach?
Originates from the lesser wing of the sphenoid bone, immediately above the optic foramen
It attaches to the superior tarsal plate of the upper eyelid
What is the innervation of the LPS?
innervated by the oculomotor nerve (CN III)
What are the 4 recti muscles of eye?
superior rectus
inferior rectus
medial rectus
lateral rectus
Where do the 4 recti eye muscles originate from?
common tendinous ring at back of orbit
What is superior rectus’ innervation and role in the eye?
Oculomotor nerve (CN III)
Upward movement
What is inferior rectus’ innervation and role in the eye?
Oculomotor nerve (CN III)
Downward movement
What is medial rectus’ innervation and role in the eye?
Oculomotor nerve (CN III)
Adduction
What is lateral rectus’ innervation and role in the eye?
Abducens nerve (CN VI)
Abducts the eye
Where does the superior oblique originate from and attach to?
Originates from the body of the sphenoid bone at posterior orbit
Its tendon passes through a trochlear and then attaches to the sclera of the eye, posterior to the superior rectus
Where does the inferior oblique originate from and attach to?
Originates from the anterior aspect of the orbital floor
Attaches to the sclera of the eye, posterior to the lateral rectus
What is the role of the superior oblique in the eye and its innervation?
Depresses, abducts and medially rotates the eyeball
Trochlear nerve (CN IV)
What is the role of the inferior oblique in the eye and its innervation?
Elevates, abducts and laterally rotates the eyeball
Oculomotor nerve (CN III)
What can the outer ear be divided into?
External acoustic meatus
Pinna (auricle)
What can the outer ear be divided into?
External acoustic meatus
Pinna (auricle)
What is the function of the pinna?
capture and direct sound waves towards the external acoustic meatus
What is the tympanic membrane?
a connective tissue structure
attached to malleus
articulates to incus
Where is the middle ear?
within the temporal bone
extends from the tympanic membrane to the lateral wall of the inner ear
What is the function of the middle ear?
transmit vibrations from the tympanic membrane to the inner ear via the auditory ossicles
What are the 3 auditory ossicles (bones)?
the malleus (largest, most lateral), incus and stapes (smallest)
What do the ossicles link and why?
linking the tympanic membrane to the oval window of the internal ear
transmit sound vibrations
What does the stapedius muscle attach to and what is its innervation?
attaches to the stapes, and is innervated by the facial nerve.
What is tensor tympani attached to and what is it innervated by?
attaches to the handle of malleus, pulling it medially when contracting
innervated by the tensor tympani nerve, a branch of the mandibular nerve
What is the function of the inner ear?
- To convert mechanical signals from the middle ear into electrical signals, which can transfer info to the auditory pathway in the brain
- To maintain balance by detecting position and motion
Where is the inner ear?
located within the petrous part of the temporal bone
It lies between the middle ear and the internal acoustic meatus
Which 3 bones make up the bony labyrinth of the inner ear and which fluid is inside them?
composed of the cochlea, vestibule and three semi-circular canals
perilymph fluid
What is the innervation of the inner ear and how does the nerve divide?
vestibulocochlear nerve (CN VIII)
enters the inner ear via the internal acoustic meatus, where it divides into the vestibular nerve (responsible for balance) and the cochlear nerve (responsible for hearing)
Which nerve passes through inner ear but doesn’t innervate it?
Facial CN VII
Where is white and grey matter?
White matter in deeper parts of brain
Grey matter on cerebral cortex surface
What are sulci and gyri?
sulci (grooves or depressions)
gyri (ridges or elevations)
What divides the two hemispheres?
the longitudinal fissure
Where and what is the falx cerebri?
an arched crescent of dura lying in longitudinal fissure
What does the central sulcus separate?
frontal and parietal lobes
What does the lateral sulcus separate?
frontal and parietal lobes from the temporal lobe
Where is the precentral gyrus and what is it for?
directly anterior to central sulcus
location of primary motor cortex
Where is the postcentral gyrus and what is located there?
directly posterior to central sulcus
location of primary somatosensory cortex
Where is the superior temporal gyrus and what is it responsible for?
ridge located inferior to lateral sulcus
responsible for the reception and processing of sound
What are the functions of the meninges?
Provide a supportive framework for the cerebral and cranial vasculature
Acting with cerebrospinal fluid to protect the CNS from mechanical damage
Where is the dura mater?
directly underneath the bones of the skull and vertebral column
What are the two layers of the dura?
Outer periosteal of cranial dura line the interior of the skull, sends blood vessels and fibrous processes into the cranial bone
Inner meningeal layer completely envelopes CNS, tube of dura seen around spinal cord and tubular sheaths for cranial nerves
Are the dura layers fused?
The periosteal dura and meningeal dura are tightly fused together, except in a few places where they separate to form the dural venous sinuses
What is the dura mater like?
thick, tough, and inextensible
Where are the dural venous sinuses and what are they responsible for?
located between the two layers of dura mater
Responsible for the venous drainage of the cranium and empty into the internal jugular veins
What is the blood supply to the dura and what is its innervation?
primarily from the middle meningeal artery and vein
innervated by the trigeminal nerve (V1, V2 and V3)
Where do the dural folds come from and what is in them?
The meningeal layer of dura mater folds inwards upon itself to form four dural folds
Project into the cranial cavity, dividing it into several compartments – each of which houses a subdivision of the brain
What are the four dural folds?
Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphagma sellae
How many venous sinuses are in the brain?
11
Which sinuses are in the falx cerebri?
straight, superior, and inferior sagittal sinuses
Where do the internal cerebral veins run?
Within substance of brain tissue and end at surface where they become external
Where do external cerebral veins run?
Surface of the brain, crossing subarachnoid space to drain into dural venous sinuses
What do sinuses in the brain do?
Connect major cerebral veins to internal jugular veins
Where can you find the cavernous sinus and what does it drain?
drains the ophthalmic veins and can be found on either side of the sella turcica. From here, the blood returns to the internal jugular vein via the superior or inferior petrosal sinuses
What is clinically significant about the cavernous sinus?
Contains 5 cranial nerves and the internal carotid artery
Very close to pituitary gland
What is the arachnoid mater?
the middle layer of the meninges, lying directly underneath the dura mater
What are 3 features of the arachnoid mater?
layers of connective tissue
avascular
does not receive any innervation
How does CSF re enter circulation?
Small projections of arachnoid mater into the dura (known as arachnoid granulations) allow CSF to re-enter the circulation via the dural venous sinuses
What do the sub-arachnoid cisterns contain?
CSF
What is CSF?
a clear, plasma-like fluid, that circulates within the system of cavities found within the central nervous system
Which specialized tissue produces and secretes CSF?
Choroid plexus
Where is the pia mater?
underneath the sub-arachnoid space
Features of the pia
very thin
tightly adhered to the surface of the brain and spinal cord
Follows gyri and sulci
Highly vascularised
What makes up the brainstem?
Medulla oblongata
Pons
Midbrain
What are the boundaries of the medulla?
beginning at the foramen magnum to the caudal border of the pons and bulbopontine sulcus
What are the 3 sulci/fissure of the anterior medulla?
ventrolateral sulcus
anterior median fissure
posterolateral sulcus
What and where are the pyramids of the medulla?
Paired swellings found between the anterior median fissure and the ventrolateral sulcus
Marks the position of the corticospinal tracts
Where are the olives in the medulla?
pair of swellings located laterally to the pyramids
between the ventrolateral and posterolateral sulci
Which CN extends out of the ventrolateral sulcus?
Hypoglossal CN XII
Which CN join the medulla in the posteriolateral sulcus?
CN IX, CN X, and CN XI
What are the olives?
caused by the presence of the underlying inferior olivary nucleus
concerned with the control of movement
What is the inferior cerebellar peduncle and what does it form?
a thick bundle of white matter passing into the cerebellum
forms the posterolateral margin of the medulla
What marks the midline of the posterior medulla?
Posterior median sulcus
What and where is the gracile tubercle?
an elevation in the dorsal medulla, in the floor of the fourth ventricle
created by the underlying gracile nucleus
What is the gracile fasciculus?
found throughout the spinal cord
begins at the caudal end of SC
comprises long ascending fibers from different spinal nerves
Carries fine touch, vibration, 2 point discrimination and proprioception from the lower limb
What does the gracile nucleus do?
one of the dorsal column nuclei
sensation of fine touch and proprioception of the lower body
contains second-order neurons of the dorsal column-medial lemniscus pathway
receive inputs from sensory neurons of the dorsal root ganglia and send axons that synapse in the thalamus.
What’s the difference between gracile and cuneate fasciculus?
Cuneate lateral to gracile
Cuneate = upper limb
Gracile = lower limb
What is the cuneate tubercle?
an enlargement at the end of the cuneate fasciculus that is produced by cuneate nucleus
What does the cuneate fasciculus do?
Carries fine touch, vibration, 2 point discrimination and proprioception from the upper limb
Where is the 4th ventricle?
situated in front of the cerebellum and behind the pons and upper half of the medulla oblongata
What is the function of the tegmentum?
Coordination of movement, pain processing, alertness
Which CN nuclei are in the tegmentum?
CN IX, X, XI, XII
What does the pons develop from?
the embryonic metencephalon
What is found in basilar sulcus of pons?
Basilar artery
Which cranial nerves originate from the ventral surface of the pons?
CN V (trigeminal), CN VI (aducens) , CN VII (facial) , CN VIII (vestibulocochlear)
What are the two major components of the pons?
Tegmentum
Ventral pons
What does the ventral pons do and contain?
Contains the pontine nuclei, which are responsible for coordinating movement
Fibres from the pontine nuclei cross the midline and form the middle cerebellar peduncles on their way to the cerebellum
What is the reticular formation?
a set of nuclei found throughout the brainstem that are responsible for arousal and attentiveness
partly formed by tegmentum
What are the descending corticospinal tracts in pons responsible for?
responsible for voluntary motor control of the body
What are the descending corticobulbar tracts in pons responsible for?
responsible for voluntary motor control of face, head and neck.
What are the ascending medial lemniscus tracts in pons responsible for?
fine touch, vibration and proprioception
What are the ascending spinothalamic tracts in pons responsible for?
responsible for pain and temperature sensation
Where are the main sensory nucleus and the trigeminal motor nucleus?
Midpons
What is the blood supply to the pons?
pontine arteries, branches of the basilar artery
A smaller part from the anterior inferior cerebellar artery and the superior cerebellar artery (AICA and SCA)
What are the 2 main parts of the midbrain?
Tectum
Paired cerebral peduncles
What separates the 4 colliculi of the tectum?
cruciform sulcus
What does the superior brachium (lateral to colliculi) convey?
Visual info from lateral geniculate body to superior colliculi
What does the inferior brachium (lateral to colliculi) convey?
Auditory info from medial geniculate body to inferior colliculi
Where is the tectum in the midbrain?
posterior to the cerebral aqueduct
What does the interpeduncular fossa separate?
The paired cerebral peduncles
Which nerve exits between the paired cerebral peduncles?
oculomotor nerve (CNIII)
Which four fibre tracts runs in crus cerebri and where are they?
Frontopontine fibres – located most medially.
Corticospinal fibres – motor fibres from the primary motor cortex.
Corticobulbar tracts – motor fibres from the primary motor cortex.
Temporopontine fibres – located posterolaterally
Where is the pineal gland?
lies in the depression between the superior colliculi
attached to the roof of the third ventricle near its junction with the mid-brain
What is the function of the pineal gland?
produces melatonin, a serotonin-derived hormone, which affects the modulation of sleep patterns in both seasonal and circadian rhythms
What is the hindbrain divided into?
Medulla oblongata (myelencephalon)
Pons (metencephalon)
Cerebellum (metencephalon)
What is the midbrain divided into?
Tectum (dorsal to cerebral aqueduct)
Cerebral peduncle (ventral to aqueduct, divided into tegmentum and crus cerebri)
What are the crura cerebri (singular crus)?
Large bundles of white matter emerging from cerebral hemispheres which pass backwards and downwards to meet at top of pons
Form the cerebral peduncles visible
What is the forebrain divided into?
Diencephalon (thalamus and hypothalamus)
Telencephalon (cerebral cortex, basal ganglia)
What is the dura mater?
A fibrous sheet with white collagen and few elastic fibres arranged in dense laminae (often of parallel fibres)
2 layers: outer endosteal and inner meningeal (dura mater proper)
What is the arachnoid mater?
Poorly vascularised membrane of loos connective tissue (collagen, elastin and reticulin fibres)
Loosely covers brain without following gyri and sulci
What is the pia mater?
Very adherent to entire surface of CNS
Follows folds
What separates the pia from the arachnoid?
Subarachnoid space with CSF
What is white matter?
Formed by collections of nerve fibres wrapped in fatty myelin sheaths (few or no neuronal somata)
What forms the grey matter?
Aggregations of neuronal cell bodies and local processes
What is the neuropil?
Within grey matter, network of intermingled and interconnected neuronal processes occupying space between neuronal cell bodies
What is the cortex?
Outer surface of the brain formed by flatter sheets of neurons
How are the grey and white matter arranged in the spinal cord?
Grey matter forms core butterfly shape
Surrounded by white matter
What is the corpus callosum?
Large bundle of white matter connecting 2 hemispheres
What are the mammilary bodies?
2 rounded eminences behind the optic chiasma
Where is the interpeduncular fossa?
Space between the crura roofed over by arachnoid
Where is the hypothalamus?
Behind the optic chiasma up to mammilary bodies
Where is the pons?
Immediately behind where the crura cerebri meet in the midpoint
Forms bridge of neural tissue between midbrain and medulla
Where is the medulla oblongata?
From caudal pons to spinal cord
Where is the parietal lobe?
Central sulcus to occipital lobe
Left usually dominant
What is parietal lobe important for?
Dominant lobe important for perception, interpretation of sensory info, formation of idea of complex motor response
Supramarginal and angular gyrus of dominant for language and maths
Non-dominant lobe for visuospatial functions
What is the frontal lobe for?
Motor function
Problem solving
Spontaneity
Memory
Language
Judgement
Personality
Impulse control
Social and sexual behaviour
Where is the prefrontal cortex and what is it important for?
Anterior frontal lobe
Higher cognitive functions
Personality
Where is Broca’s?
Left inferior frontal gyrus
Language production and also comprehension
What is in the posterior frontal lobe?
Motor and premotor areas
What does the temporal lobe contain?
Primary auditory cortex
Hippocampus
Amygdala
Wernicke’s area
Where is Wernicke’s?
Superior temporal gyrus of L hemisphere
Understanding spoken word
Where is the auditory cortex?
Around lateral fissure
What does the occipital lobe contain?
Primary visual cortex and visual association cortex
What does the limbic system do? (5Fs)
Feeding (satiety & hunger)
Forgetting (memory)
Fighting (emotional response)
Family (sexual reproduction and maternal instincts)
Fornicating (sexual arousal)
Where is the cerebellomedullary cistern?
between the medulla anteriorly and the cerebellum posteriorly
receives CSF from 4th ventricle via the median and lateral apertures
What does the cerebellomedullary cistern contain?
Vertebral arteries
CN 9-11
Choroid plexus producing CSF
Where is the pontine cistern?
anterior to the pons
What does the pontine cistern contain?
Basilar artery
anterior inferior cerebellar artery
abducens nerve
superior cerebellar arteries
What does the interpeduncular fossa contain?
circle of willis
What does the superior cistern contain and where is it?
Great cerebral vein
Pineal gland
Between posterior end of corpus callosum and superior cerebellum
What does the cistern of lateral fissure contain?
Middle cerebral artery
What do the cisterna ambiens encircle?
Midbrain
What makes up the blood brain barrier?
Tight junctions between endothelial cells to prevent molecules passing
No fenestrations in blood vessels
Pericytes in membrane wrap around endothelial cells and regulate capilliary flow
Astrocytic end feet restrict molecule flow into CNS parenchyma
What is found in the subarachnoid space?
CSF
arachnoid trabeculae
cerebral arteries and veins
cranial and spinal nerves
What is the purpose of the subarachnoid space?
House CSF to cushion brain and spinal cord
provide nutrients
remove waste
Support and stabilize brain and spinal cord
What do the vertebral arteries supply?
Posterior cerebrum and contents of posterior cranial fossa
Provide 20% of total blood to brain
What do the internal carotid arteries supply?
Anterior and middle parts of cerebrum and diencephalon
80% total blood supply to brain
What does the internal carotid give rise to and what do these supply?
Ophthalmic artery – supplies the structures of the orbit.
Posterior communicating artery – acts as an anastomotic ‘connecting vessel’ in the Circle of Willis
Anterior choroidal artery – supplies structures for motor control and vision.
Anterior cerebral artery- supplies part of cerebrum
What does the internal carotid continue as?
Middle cerebral artery
What do the vertebral arteries get to brain through?
holes in the transverse processes of the cervical vertebrae, known as foramen transversarium
Enter cranial cavity via foramen magnum
What are the branches of the vertebral arteries before they become basilar?
Meningeal branch – supplies the falx cerebelli
Anterior and posterior spinal arteries – supplies the spinal cord
Posterior inferior cerebellar artery – supplies the cerebellum
How does the basilar artery terminate?
bifurcating into the posterior cerebral arteries
What is a berry aneurysm?
Sac-like outpouching from an intracranial artery
Progressively enlarge then rupture suddenly
Most often on anterior communicating
Where does the basilar artery run?
Anterior median fissure of pons
Where does vertebral become basilar?
midline lower border of pons
Where are the internal cerebral veins?
Run within substance of brain and end when they reach the surface
Where are the external cerebral veins?
Run on surface of brain
Cross subarachnoid space to drain into dural venous sinuses
What does the cavernous sinus contain?
Oculomotor nerve (CN III)
Trochlear nerve (CN IV)
Abducens (CN VI)
Ophthalmic (V1) and maxillary (V2)
Internal carotid (only time an artery passes through a venous structure)
Where are the cavernous sinuses?
located within the middle cranial fossa, on either side of the sella turcica of the sphenoid bone
enclosed by dura
Where is the lacrimal gland?
Inside lateral margin of orbit
adjacent to lateral margin of LPS
What does the cerebellum develop from?
Metencephalon
What separates cerebellum and pons?
4th ventricle
What makes up the cerebellum?
2 hemispheres and the vermis between
What separates anterior lobe of cerebellum from posterior lobe?
Primary fissure
What are the 3 lobes of the cerebellum?
Anterior
Posterior
Flocculonodular
What are the 3 zones of the cerebellum?
Vermis
Intermediate
Lateral
What does the cerebrocerebellum do?
formed by the lateral hemispheres
involved in planning movements and motor learning
receives inputs from the cerebral cortex and pontine nuclei, and sends outputs to the thalamus and red nucleus
regulates coordination of muscle activation and is important in visually guided movements
What does the spinocerebellum do?
comprised of the vermis and intermediate zone of the cerebellar hemispheres
involved in regulating body movements by allowing for error correction
receives proprioceptive information
What does the vestibulocerebellum do?
involved in controlling balance and ocular reflexes, mainly fixation on a target
It receives inputs from the vestibular system, and sends outputs back to the vestibular nuclei
What is the blood supply to the cerebellum?
Superior cerebellar artery
Anterior inferior cerebellar artery
Posterior inferior cerebellar artery
What are the openings into the 4th ventricle?
2 lateral aperatures in side wall (of Luschka)
Median aperature in roof (Magendie)
What forms the boundaries of the 4th ventricle?
Lateral walls: formed by cerebellar peduncles
Roof: formed by cerebellar peduncles, superior and inferior medullary velum
Floor: formed by rhomboid fossa
What forms the floor of the 4th ventricle?
posterior surface of the pons
junction of the medulla and pons
upper part of the posterior surface of the medulla
(median sulcus with median eminence either side)
What is the rhomboid fossa?
diamond shaped floor of 4th ventricle limited laterally by cerebellar peduncles and posteriorly by gracile and cuneate tubercles
What is the hypoglossal trigone?
Medial triangular area overlying the hypoglossal nerve nucleus
What is the facial colliculus?
Rounded swelling caused by fibres of the facial nerve in pons
At level of superior fovea
What does the median sulcus divide?
Rhomboid fossa into triangular left and right halves
What is the vagal trigone?
Intermediate triangular area overlying the vagus nerve nucleus
What is the vestibular trigone?
Lateral triangular area overling the vestibulocochlear nerve nucleus
What is the obex?
Inferior apex of rhomboid fossa
Where is the thalamus and what is it?
Superolateral walls of 3rd ventricle
Part of diencephalon
Major subcortical relay for ascending info
Where is the hypothalamus and what does it do?
Ventral diencephalon
From optic chiasm to posterior mammilary body
Important for homeostasis and neuroendocrine control
What and where is the fornix?
Bundle of white matter beneath the body of the corpus callosum
Connects hippocampus with diencephalon
What and where is the hippocampus?
in the floor and medial wall of the temporal horn of the lateral ventricle
involved in long term memory formation
What does the medial geniculate nucleus do?
Relays auditory info from the midbrain to the auditory cortex and inferior colliculi
What does the lateral geniculate nucleus do?
Relays visual info from the optic nerve to both the visual cortex and superior colliculi
What does the hypothalamic sulcus do?
Divide the diencephalon into dorsal and ventral parts
What do association fibres do?
Link cortical regions within one hemisphere
Can be short or long (spanning lobes)
What is the longitudinal fasciculus made of?
Association fibres
What are the 3 types of white matter fibres?
Association
Commissural
Projection
What do commissural fibres do?
Link similar functional areas of 2 hemispheres
E.g. corpus callosum
What do projection fibres do?
Link cortex with subcortical structures
Where is the cingulate gyrus?
Immediately dorsal and parallel to corpus callosum
What is the uncus?
A hook shaped region of the cortex at the anterior end of the temporal lobe
Plays a role in olfaction, emotions and memory
What forms the roof of the body of the lateral ventricle?
Corpus callosum
Where is the claustrum?
Deep to: Insula and extreme capsule
Lateral to: external capsule and putamen
What is the striatum?
the main input unit of the basal ganglia
It receives excitatory glutamatergic inputs from the cerebral cortex
Where is the caudate nucleus?
an elongated C-shaped nucleus that lies anterior to the thalamus, just lateral to the lateral ventricles and medial to the internal capsule
Where is the putamen and what does it do?
laterally to the globus pallidus and medially to the external capsule
Regulates motor funcitons and employ learning
What is the globus pallidus?
a paired subcortical structure, situated medially to the putamen and composed of inhibitory GABAergic projection neurons
GP medial and GP lateral
What separates the globus pallidus and the putamen?
GP lateral separted from putamen by lateral medullary lamina
GPs separated by medial medullary lamina
Where is the internal capsule?
lateral to the thalamus and caudate nucleus, and medial to the lentiform nucleus
Where is the external capsule?
White matter between putamen and claustrum
What is the internal capsule for?
Connections between cerebral cortex and subcortical structures, brainstem & spinal cord
Carries all motor and sensory fibres to and from cortex
What is the corona radiata?
White matter fibres radiating from the internal capsule
Deep to lentiform nucleus
Features of C vertebrae
Small body
Bifid spinous process
Large triangular foramen
Transverse foramina for vertebral arteries
Features of T vertebrae
Heart shaped body
2 demi facets on superior and inferior lateral surface to attach to rib
Circular foramen
Costal facets
Features of lumbar vertebrae
Bean shaped
Large body
Short and posterior projecting spinous processes
Small triangular vertebral foramen
What are intervertebral discs?
Strong fibrocartilaginous structures between nuclei
Can withstand compression forces and allow movement
What are the 2 parts of the intervertebral discs?
Nucelus pulposus (gel of proteoglycans, collagen and cartilage cells) surrounded by annulus fibrosis (collagen, attached to vertebral bodies and posterior longitudinal ligament)
What is the spinal cord segment?
The area of the spinal cord where pairs of spinal nerves are given off
How many pairs of spinal nerves are there?
31 pairs so 31 segements
How are the spinal nerves distributed?
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
What does the dorsal root of a spinal nerve carry?
Sensory fibres
Has a dorsal root ganglion
What does the ventral root carry?
Motor
Emerges on anterolateral aspect of cord
Where do the roots join to form spinal cord and what happens?
Intervertebral foramen
Then immediately split to form dorsal and ventral rami (both have sensory and motor)
What is the cauda equina?
Bundle of the lumbar and sacral nerve roots after the termination of the spinal cord
At what level is the conus medullaris?
L2
Where does the spinal cord terminate?
L1-2
Where is the primary visual cortex?
Walls of the calcarine sulcus
What is the paracentral lobule?
U-shaped gyrus surrounding medial extension of central sulcus
Contains representations of the lower limb within the primary motor and somatic sensory areas
