Neuroanatomy Flashcards
What is the diffence between grey and white matter?
Grey matter- nerve cell bodies
White matter- myelinated axons
What allows action potentials to be conducted faster down the nerve?
Schwann cells (SCs) are a type of glial cell- make the axon myelinated
In what type of matter are synapses located?
Predominately grey matter regions
What anatomical words are used to describe the different sides of the brain and the brain stem?
BRAIN= superior, anterior, inferior and posterior
BRAIN STEM= Rostral, caudal, dorsal and ventral
What are the 4 main subdivisions of the brain?
Cerebral hemispheres (green)
Diencephalon (orange)
Brain stem (purple, yellow, red and blue)
Cerebellum (yellow)
What is a gyrus?
Ridge on the cortex of the cerebral hemispheres
What are sulcus’ and fissures?
Grooves, fissure is particularly large one
Where does conscious activity take place?
Cerebral hemispheres
What is the name of the main ridge that connects the left and right hemispheres?
Corpus callusum
What are the left and the right cerebral hemispheres seperated by?
The great longitudonal fissure
What is the rim of grey matter around the cerebral hemispheres called?
Cerebral cortex
What are the different lobes and fissures seperating the lobes in the brain?
What different actions are controlled within the frontal lobe?
Planning complex movements and thinking, motor activity and speech production
What different actions are control by the parietal lobe?
Spacial awareness of body and surroundings
Somato-sensory area, recieves and process somatic information
What is processed within the occipital lobe?
Vision
What is controlled by the temporal area of the brain?
Auditory sense, language understanding
Behaviour, emotions and motivation
What are Brodmann’s areas?
Numbers allocated to describe areas of the brain
What brodmann numbers are assigned to:
- Primary somatosensory area
- Primary motor
- Primary visual
- Broca’s (motor speech) area
- Primary auditory
Primary somatosensory= 1,2,3
Motor= 4
Visual= 17
Broca’s= 44,45
Primary auditory= 41,42
What are the different types of communicating fibres in the brain?
Association fibres- within hemispheres
Commissural fibres- between hemispheres
Projection fibres- cortex to sub-cortical areas such as spinal cord
What is the diencephalon and what are the different parts of it?
Area under corpus collosum, operates at subconscious level.
Epithalamus, thalamus, subthalamus and hypothalamus
What is the epithalamus?
Regulates the sleep cycle
What is the thalamus?
Single structure with two parts. All sensory information collects here and is then sorted to another part of the brain
What is the hypothalamus?
Linked with the pituitary grand (regular of the endocrine system)
What are the 3 parts of the brain stem?
Midbrain (purple)
Pons (yellow)
Medulla (red)
What if the function of the cerebellum?
Co-ordinates movement
Is subconscious and attached to brain stem.
What is the anatomy of the cerebellum?
There is 2 hemispheres, linked by the vermis
Grooves are referred to as folia
The tracts that link cerebellum to brainstem are called peduncles
What are the peduncles?
Superior- attaches midbrain to cerebellun
Middle- attaches pons to cerebellum
Inferior- attaches medulla to cerebllum
What is the final part of the brain before the spinal cord?
The medulla oblongata
Where are the two swellings in the spinal cord?
Cervical and lumbosacral
What does the spinal cord taper in and at what vertebrae level?
Conus medullaris- L1/L2
How many pairs of bilateral spinal nerves are there and how are they split up?
31 bilateral pairs
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
Where is the white and grey matter located in the spinal cord?
Opposite to brain, white matter is on the outside and grey on the inside.
White matter stains grey however, as in this picture below
Why is there different amounts of white matter as you go down the spinal cord?
White matter is the myelinated axons or ‘cabling’, as we move down the spinal cord more nerves have split off so there is less cabling or white matter
What side of the spinal cord are sensory and motor nerves found?
Sensory found on the dorsal (posterior)
Motor found on the ventral (anterior)
How can you tell what side of the spinal cord is the dorsal side?
Grey matter on the dorsal side reaches the edge of the spinal cord
What happens to the dorsal and ventral axons after/before they reach the spinal cord?
They intermingle to form a single nerve
What are the meninges?
Covering of the nervous system.
All brain and spinal cord are surrounded by it
What are the 3 layers of the meninges?
Dura mater- thick and rubbery layer on the outside
Arachnoid mater- middle layer, thinner, has finger like projections which create a web like pattern causing there to be sub-arachnoid space
Pia mater- thin, outer layer of brqin that follows sulcus pattern
What is contained within the arachnoid mater?
Cerebral spinal fluid
Blood vessels
What are the two main structures that the dura mater folds inself into?
The falx cerebri, which runs along the great longitudinal fissure
Then folds out into wing like structures between the occipital lobe and the cerebellum- tentorium cerebelli
What are the two main routes of blood supply to the brain?
Common carotid artery (internal)
Vertebrae artery (branch of subclavian)
What are the 3 main branches of artery that arise from the circle of willis/anterior circle?
Left and right anterior, middle and posterior cerebral arteries
What different areas of the brain do the cerebral arteries supply?
BLUE= anterior
RED= middle
YELLOW= posterior
How is blood drained from the brain?
The dura has holes in it where the blood is drained- called dural venous sinuses.
Ultimately these drain into the internal jugular vein
What are the ventricles of the brain and what are their names?
Interconnected series of midline chambers within the brain
2 lateral, third and fourth
What is the function of the brain ventricles?
Produce and store cerebral spinal fluid
CSF passes from lateral ventricles to third then fourth then to the central spinal canal
What is the swelling on the dorsal route called?
Dorsal root ganglion- collection of neuronal cell bodies outside the CNS
Where is it decided what route the different sensory modalities will travel up the spinal cord?
Dorsal root ganglion
What are the 3 main ascending pathways in the spinal cord?
Dorsal column- 3rd order
Spinothalamic pathway- 3rd order
Spinocerebellar pathway- 2nd order
What sensory modalities does the dorsal column pathway carry?
Discriminative touch, vibration and proprioception
Where do each of the neurone changes occur in the dorsal column?
1st → 2nd grey matter of medulla
2nd then cross to the contralateral side and travel up
2nd → 3rd Thalamus, cell bodies of 3rd neurones found in the VPL nucleus
How do neurones get from the thalamus to the pre-frontal cortex in the dorsal column pathway?
The internal capsule, a two-way white matter tract replaying information
What are the 3 parts of the internal capsule?
Posterior limb by thalamus
The genu (‘bend’)
Anterior limb by PFC
What are the 2 main bundles of nerves in the cervical part of the dorsal column?
The dorsal column is formed by two large fasciculi (bundles of nerve fibers) running through the posterior spinal cord:
- fasciculus gracilis (lower limb/body info
- fasciculus cuneatus (upper limb)
Where does the dorsal column pathway swap sides?
The medulla
Where in the spinal. cord is the dorsal column pathway found?
What is the medial lemniscus?
A continuation of the dorsal column system in the spinal cord that conveys information to the VPL. Second order neurones
In what area of pons does the dorsal column travel?
In what area of midbrain does the dorsal coloumn travel?
What sensory modalities does the spinothalamic pathway carry?
Pain, non-discriminative touch and temperature
Where does the 1st neurone → 2nd neurone in the spinothalamic pathway?
At the substantia gelatinosa/ nucleus propius
Where does the spinothalamic pathway cross to the contralateral side?
Axons cross over the ventral white commissure to the spinothalamic tract on the opposite side
Where in the spinal cord does the spinothalamic pathway travel?
Landmark= in the white matter directly ventral to the ventral horn
What is the spinal meniscus?
Where the anterior and lateral spinothalamic tracts combine in the medulla
What path do the second order and third order neurones in the spinothalamic pathway?
2nd → 3rd at the VPL nucleus
3rd then travels via the internal capsule to the pre-frontal cortex
What sensory modalities are carried via the spinocerebellar pathway?
Proprioception information for motor coordination and posture
What are the two spinocerebellar pathways and how do they differ?
Dorsal and ventral paths
The dorsal does not cross sides, the ventral does
How do the spinothalamic pathways connect to the cerebellum?
Via the peduncles
What route does the ventral spinothalamic pathway take up the spinal cord?
1st order → 2nd order in the spinal cord grey matter, then crosses over and travels up the spinothalamic tract until the midbrain, where is crosses back over
Where does general sensory information from head and neck travel in?
Cranial nerve V, trigeminal nerve
Travels to the VPM nucleus where pain/temperature travels to medulla and touch/pressure to pons
What is a dermatome?
An area of skin supplied by a single spinal nerve
What are the two areas of 2 order axons in the dorsal column pathway?
Fascilulus cuneatus- lateral (arms)
Fasciculus gracilis (legs)- medial
What happens to the fasiculus gracilis and cuneatus in the mid medulla?
Changes from 2nd order → 3rd order
There is the nucleus gracilis connected to the fasciciulus gracillis and the same with cuneatus
What are the different arrows on the diagram pointing to?
How does the position of the medial menicus change moving rostral the brainstem?
Where is the coronal radiata?
A white matter sheet that continues inferiorly as the internal capsule and superiorly as the cortex
What are the internal arcuate fibres?
A fiber bundle that extends across the midline of the medulla. Many of the fibers consist of axons traveling from the nucleus gracilis and nucleus cuneatus to the contralateral side of the medulla where they will begin traveling up to the cortex as part of the medial lemniscus.
Where are the fasiculus cuneatus and gracillis in the medulla?
Where are the fasiculus cuneatus and gracillis in the medulla?
Where is the thalamus in the brain?
Forms the wall of the third ventricle
What are the following labels on the diagram?
What forms the boundaries of the internal capsule?
What do the different limbs of the internal capsule contain?
Anterior limb= fibres associated with higher functions
Posterior limb= major ascending somatosensory and descending motor fibres
Where is the somatosensory cortex located?
On the post-central gyrus (immediately posterior to the central sulcus)
What arteries supply blood to the sensory cortex region?
Anterior cerebral artery- supplies blood to the lower limb area
Middle cerebral- supplies blood to facial region
Where are the axons of first order neurones?
One portion of the axon is located in the periphery, collecting information from a peripheral receptor
The other portion of the axon will carry sensory information into the spinal cord via the dorsal root, where it will either ascend in a white matter tract or synapse
Whata re the different areas of spinal cords, as shown below?
Where is non-special sensory information carried from in the head and neck?
Trigeminal nerve
Where do the cell bodies of most sensory neurones related to the trigeminal nerve lie?
In the trigeminal ganglion, a structure found out with the brain stem
Where are the 3 sensory nuclei that trigeminal neurones synapse at?
The mesencephalic nucleus
Chief sensory nucleus
Nucleus of the spinal tract of the trigeminal
What do the different trigeminal nuclei carry information for?
Mesencephalic (top)- proprioception
Chief sensory (middle)- touch and pressure
Nucleus of the spinal tract of the trigeminal (bottom)- pain and temperature
What are the following labels on the diagram?
Where do the ventral and sorsal spinocerebellar tracts enter the cerebellum?
Ventral= through superior cerebellar peduncle
Dorsal= inferior cerebellar peduncle
What information is carried along the spinocerebllar tract?
Relative stretch from muscles, stretch from tendons, output from joint receptors and information about pressure on skin and superficial fascia
What is located in the pre-central gyrus?
Primary motor cortex
What is located in the post-central gyrus?
Primary somatosensory cortex
What are the labels on this diagram?
What is Broca’s area?
Cocerned with the motor control of speech. Located predominately in the dominant cerebral hemisphere, usually the left one.control of speech. Located predominately in the dominant cerebral hemisphere, usually the left one.
What is the corticobulbar tract?
Corticobulbar tract carries upper motor neuron input to motor nuclei of trigeminal, facial, glossopharyngeal, vagus, accessory, and hypoglossal nerves.
What is the corona radiata?
Fibres from the cortical surface to the internal capsule.
Looks like a ray of sun
Where are fibres from the corticospinal and corticobulbar tracts located in the internal capsule?
Posterior limb of the internal capsule
Corticospinal fibres= nearer the retrolenticular region
Cortibulbar fibres= nearer the genu
What are the labels on the diagram?
Where are the cell bodies of lower motor neurones located?
Ventral grey horn- at lamina 9
What type of neurone are motor neurones mainly?
A-alpha
These are the biggest and fastest
Where do the axons of lower motor neurones travel to?
Travel from the ventral grey horn, into the spinal nerve (mixed with other axons) then into the periphery to neuromuscular junctions
What receptor is present in neuromuscular junctions?
Nicotinic- acetylcholine mediated
What is the corticospinal pathway?
For control of voluntary and precise movement
Also known as a pyramidal pathway
What side does the corticospinal tract innervate?
99% innervate the lower motor neurones on the contralateral side
Where are the first order motor neurone cells in the corticospinal tract located?
Located in the cortical grey matter (grey matter rim), in layer 5- Betz cells
Where is the crus cerebeli?
The white matter at the front of the midbrain
What is the pathway taken for the corticospinal tract through the brain stem?
Internal capsule → Crus Cerebeli of midbrain → pontine corticospinal tracts →pyramids of medulla → dessucation of the pyramids
What is the gap seen in cross sections of the pons and the medulla?
The 4th ventricle
Where are the pyramids?
Triangular shaped structures on the ventral aspect of the medulla
What are the pontine corticospinal tracts?
Located in the pons, darker circles seen.
What are the labels on the following diagram?
What are the lateral and ventral tracts of the corticospinal tract?
Ones that dessucated at the pyramids= lateral
Ones that dessucate in the spinal cord just before they synapse with lower motor neurons.= ventral
Where are the lateral and ventral corticospinal tracts in the spinal cord?
What is the corticobulbar pathway?
Only goes as far as the brain stem- reaches cranial nerves
Corticobulbar tract carries upper motor neuron input to motor nuclei of trigeminal, facial, glossopharyngeal, vagus, accessory, and hypoglossal nerves
What are the extra-pyramidal motor pathways?
Originate in the brainstem, carry motor fibres to the spinal cord. They are responsible for the unconscious, reflexive or responsive control of musculature
What are the different extra-pyramidal tracts shown below?
Red= rubrospinal tract
Blue= vestibulospinal tract
Green= Tectospinal tract
Pink= reticulospinal tract
What occurs in lower motor neuron loss?
Affected muscles= weak or paralysed
There is profound muscle atrophy
Tendon reflexes are weak or absent
What occurs in upper motor neuron loss?
Voluntary movements of affected muscles= weak
Slow wasting of muscle
Spasticity
Positive Babinski reflex
What is the babinski reflex?
Occurs in upper motor neurone loss
What is the basal ganglia?
An extra-pyramdial structure that reinforces motor movements
A group of are a group of subcortical nuclei
What are the two stars on the diagram?
Red= subthalamic nucleus
Black= hypothalamus
What are the red and black stars on the diagram?
Red= substantia niagra
Black= red nucleus
What is the vestibulospinal pathway?
Extra-pyramidal motor pathway
Receives info from labyrinthine system and cerebellum
Activates extensor motor neurones concerned with maintenance of anti-gravity posture
What is the rubrospinal pathway?
Extra-pyramidal motor pathway
Recieves info from cortex and cerebellum
Activates motor neurones of flexor muscles
What is the reticulospinal pathway?
Extra-pyramidal motor pathway
Receives info from hypothalamus, activates motor neurones concerned with reflex activity, muscle tone, breathing and circulatory system
What is the tectospinal pathway?
Extra-pyramidal motor pathway
Receives info from the visual system
Activates motor neurones reflex response to visual stimuli
What is the indirect and direct pathway of the basal ganglia?
What are the effects of a damaged substantia niagra in Parkinson’s?
Can no longer positively or negatively affect the indirect pathway so movements are not reinforced and undesirable movements go ahead
What is the striatum?
The caudate nucleus and the putamen
What do the direct pathway and indirect pathway do in the basal ganglia?
Direct= promotes movement
Indirect= inhibits movement
What neurotransmitter does the substantia niagra use?
Dopamine, activates and inhibits the striatum
What shape is the caudate nucleus?
A tadpole like shape that follows the curvature of the lateral ventricle
What are the following labels?
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What is the name of all the cranial nerves?
1 = Olfactory nerve
2= Optic nerve
3= Oculomotor nerve
4= Trochlear nerve
5= Trigeminal nerve
6= Abducens nerve
7= Facial nerve
8= Vestibulocochlear nerve
9= Glossopharyngeal nerve
10= Vagus nerve
11= Accesory nerve
12= Hypoglossal nerve
What is a mnemonic for the cranial nerves?
Oh once one takes their anatomy final very good vacations are heavenly
What are the cranial nerves on the base of the brain?
What are the cranial nerve labels seen below?
What is the function of CN1?
Sensory- Perceives odours in the nasal cavity (smell)
What is the course of CN1?
- Travels from the olfactory epithelium in the top portion of the nasal cavity.
- Through the cribriform plate (exit foramen) to the olfactory bulb.
- Then through the olfactory tract to the primary olfactory cortex. Does not go back to brain stem- arrises from uncus (the innermost part of the temporal lobe)
What is CN 1?
Optic nerve
What are the labels on the diagram?
What is the mnemonic for the cranial nerve functions?
Some say marry money but my brother says big brains matter more
What is CN 2?
Optic nerve
What function does cranial nerve 2 have?
Sensory- perceives light in the eye
What is the course of the optic nerve?
- Information from temporal visual field goes to nasal side of retina and decussates
- Info from other nasal field goes to temporal side and does not deccusate
- Travels up the optic tract to the superior colliculus in midbrain (reflexes)
- Info for visions travels to the lateral geniculate nucleus of the thalamus (vision) and then through optic radiations to the occipital visual cortex
What are the missing labels on the diagram?
What is the exit foramen for the optic nerve?
Optic canal
What is cranial nerve 3?
Oculomotor nerve
What is the function of CN3?
Function is eye movement and dilating pupil/focusing lense
What is the exit foramen of the oculomotor nerve?
Superior orbital fissure
What is the course of the oculomotor nerve?
Arrises from the anterior surface of midbrain, then travels through the lateral wall of cavernous sinus, within the common tendinous ring (a ring of fibrous tissue surrounding the optic nerve at its entrance at the apex of the orbit) and splits in superior and inferior branches.
What are the two branches of the oculomotor nerve?
Superior and inferior branches
Superior= superior rectus and levator palpebrae superioris – raises eyelid
Inferior= Inferior oblique, Inferior rectus, Medial rectus, Sphincter pupillae – dilates pupil and Ciliary muscle - focus
What are the following labels?
What is CN4?
Trochlear nerve
What are the function of CN4?
Movement of superior orbital muscle (movement of eye)
What is the exit foramen of trochlear nerve?
superior orbital fissure
What is the course of trochlear nerve?
Emerges from the posterior aspect of the brain stem then travels down the lateral wall of cavernous sinus and outside common tendinous ring
What is CN 5?
Trigeminal nerve
Where does the trigeminal nerve arrise from?
Emerges from brain stem, lateral to pons
What is the shape of the trigeminal ganglion?
What are the 3 main branches of the trigeminal nerve?
Opthalmic- sensory
Maxillary- sensory
Mandibular- motor and sensory
What is the function of the opthalmic nerve?
Function= sensation to skin above eye and nasal cavity. Also dilates pupil (autonomic)
What is the course of the opthalmic nerve?
Travels on the lateral wall of cavernous sinus, before splitting into 3 branches (Nasociliary, Lacrimal, Frontal), then exits via the superior orbital fissure
What is the function of the maxillary branch?
Function= sensation to skin between eye and mouth, maxillary teeth. Autonomic to lacrimal, nasal, palatine and pharyngeal glands.
What is the course of the maxillary nerve?
Gives off two branches, zygomatic and infraorbital
Passes through pterygopalatine fossa
Gives off another 4 branches, Nasopalatine, Greater palatine, Lesser palatine and Pharyngeal
What is the exit foramen of the maxillary nerve?
Foramen rotundum
What nerve is this?
Ophthalmic nerve
What nerve is this?
Maxillary nerve
What nerve is this?
Mandibular nerve
What is the function of the mandibular nerve?
- Function is to collect sensory to temporal region and the mandibular region
- Autonomic innervation to the salivary glands and motor innervation to the muscles of mastication
What is the exit foramen of the mandibular nerve?
Exit foramen= foramen ovale
What are the divisions of the mandibular nerve?
- Anterior division= motor and buccal branches
- Posterior division= lingual, inferior alveolar and auriclotemporal
What nerve gives motor innervation to medial pterygoid, tensor tympani and tensor veli palatini?
Mandibular nerve
What is CN6?
Abducens nerve
What is the function of the abducens nerve
Eye movement via lateral rectus
What is the course of the abducens nerve?
Travels within the pontomedullary junction, deep in cavernous sinus and then within common tendinous ring
What is the exit foramen of the abducens nerve?
Superior orbital fissure
What nerve travel through the common tendinous ring?
- Superior division of the oculomotor nerve (CNIII)
- Nasociliary nerve (branch of ophthalmic nerve)
- Inferior division of the oculomotor nerve (CNIII)
- Abducens nerve (CNVI)
- Optic nerve
- (superior to inferior)
What is CN7?
Facial nerve
What is the functions of the facial nerve?
Function= muscles of facial expression (motor) taste (sensory) and salivary and lacrimal glands (autonomic)
What are the two roots of the facial nerve?
- Course- emerges from Pons in to distinct roots; the facial motor root (motor) and intermediate nerve (sensory and parasympathetic info)
- The roots remain distinct as they enter the internal acoustic meatus of the temporal bone and then they merge
What is the exit foramen of the facial nerve?
Stylomastoid foramen
*Also has entrance foramen- internal acoustic meatus
What are the main branches of the facial nerve?
Greater petrosal for glands
Chorda tympani for taste
Last part, passed through patotid gland and gives off TZBMC nerves
What does to zanzibar by motor car mean?
Temporal nerve
Zygomatic nerve
Buccal nerve
Marginal mandibular
Cervical
What are the following nerves?
What is CN 8?
Vestibulocochlear nerve
What is the function of CN 8?
Hearing and balance
Where do the cranial nerves arrise from?
1= uncus
2= optic chiasm
3 and 4= brain stem
5= pons
6,7 and 8 = pontomedullary junction
9,10,11 and 12= medulla
What is the course of the vestibulocochlear nerve?
Pontomedullary junction, travels with facial nerve out of the internal acoustic meatus. Does not exit bone, but stays within the petrous part of the temporal bone
What is the exit foramen of the vestibulocochlear nerve?
Internal acoustic meatus
What are the branches of the vestibucochlear nerve?
- Vestibular nerve (posterior division)- records rotational movement of head and position of head
- Cochlear nerve (anterior division)- responsible for hearing and localisation of sound.
What is CN 9?
Glossopharyngeal nerve
What is the function of CN 9?
- Function= sensory info from oropharynx, middle ear, carotid body and sinus as well as posterior 1/3 tongue.
- Motor innervation to stylopharyngeus muscle
- Autonomic innervation to the parotid gland
What is the course of the glossopharyngeal nerve?
Arrises from the medullary Olive and travels between the internal jugular vein and internal carotid artery in neck.
What is the exit foramen of the glossopharyngeal nerve?
Exit foramen= jugular foramen
What are the branches of the glossopharyngeal nerve?
- Tympanic
- Stylopharyngeus
- Tonsillar
- Pharyngeal
- Lingual
- Carotid
What is CN 10?
Vagus nerve
What is the function of the vagus nerve?
Sensory innervation to ear, larynx and pharynx
Motor innervation to pharynx and larynx
Autonomic innervation to heart and digestive organs
What is the course of the vagus nerve?
Course- arrises from medulla posterior to the olive. Descends in the neck, thorax and abdomen.
What is the exit foramen of the vagus nerve?
Jugular foramen
What are the missing labels in the diagram?
What are the main branches of the vagus nerve and what do they innervate?
- Auricular= collects sensory information from the ear
- Pharyngeal= supplies motor innervation to muscles of pharynx and superior 1/3 of oseophagus.
- Superior laryngeal branch= motor to cricothyroid, taste from epiglottis and sensory from larynx
- Reccurent laryngeal= Gives motor to intrinsic muscles of larynx and sensory to mucosa below vocal cords. Also parasympathetic to larynx, oesophagus and trachea.
Where does the vagus nerve end up supplying?
Deep cardiac plexus = supplied by the right vagus nerve, superficial cardiac plexus= left vagus nerve.
What is CN 11?
Accessory nerve
What is the function of CN11?
Function= motor innervation of sternocleidomastoid and trapezius
What is the exit foramen of the accessory nerve?
Jugular foramen
How does the accessory nerve arrise?
Formed of a collection of rootlets from the medulla and the cervical spinal cord (enter cranium via foramen magnum) that forms one nerve
What is CN 12?
Hypoglossal nerve
What is CN 12?
Hypoglossal nerve
What is the function of CN 12?
Function= tongue movement, speech and swallowing
What is the course of the hypoglossal nerve?
Emerges from the medulla, there is convergence of rootlets then the nerve descends in neck lateral to internal and external carotid artery
What is the nucleus in the brain that recieves information about taste?
Nucleus solitaris
What cranial nerves pass through the superior orbital fissure?
Oculomotor
Trochlear
Trigeminal: Ophthalmic
Abducens
What cranial nerves pass through the internal acoustic meatus?
Facial and vestibucochlear
What cranial nerves pass through the jugular foramen
Glossopharyngeal, vagus and accessary
What nerve passes through the hypoglossal canal?
Hypoglossal nerve
What nerve passes through foramen ovale?
Mandibular branch of trigeminal
What nerve passes through foramen ovale?
Mandibular branch of trigeminal
What nerve passes through foramen rotundum?
Maxillary branch of trigeminal nerve
Whata re the cranial foramina below?
1 – superior orbital fissure
2 – foramen rotundum
3 – foramen ovale
4 – foramen spinosum
5 – hypoglossal canal
6 – foramen magnum
7 – Cribriform plate
8 – foramen lacerum
9 – internal acoustic meatus
10 – jugular foramen
(optic canal is located medial to superior orbital fissure)
What should you remember with the cranial nuclei?
They will be located in the part of the brainstem where the cranial nerve arrises from
What nerve innervates masseter?
Mandibular branch of trigeminal
What nerve innervates trapezius?
Accessory nerve
What nerve innervates the intrinsic tongue muscles?
Hypoglossal nerve
What nerve innervates superior pharyngeal constrictor?
Vagus nerve
What nerve innervates orbicularis oris?
Facial nerve
What nerve innervates levator palpebrae superioris?
Oculomotor nerve
What is Bell’s palsy?
Most common lower motor neurone palsy of the facial nerve
What are the symptoms of Bell’s palsy and why do they occur?
Hyperacusis= Non-functional stapedius muscle
Dry eye= Non-functional orbicularis oculi – makes it difficult to blink or close the eye, therefore it dries out.
Dribbling when eating= Loss of tone in facial muscles leads to difficulty in controlling food and fluid in the mouth (buccinator in cheek, orbicular oris).
What cranial nerve provides innervation to each of the extraocular muscles?
Lateral rectus= abducens
Superior oblique= trochlear
Inferior oblique, medial rectus, inferior rectus and superior rectus= oculomotor
What are the missing muscles responsible for eye of the eye movements shown?
What cranial nerve is responsible for collecting sensory information from most of the face?
What cranial nerve is responsible for collecting sensory information from most of the face?
Trigeminal nerve
What are the three cranial nerves that contribute to general sensation at the ear?
Auricular branch of vagus nerve
Facial nerve, sensory branch
Auriculotemporal nerve (branch of mandibular)
One cranial nerve perceives general sensory information from the pharynx making up the afferent limb of the gag reflex. What nerve is this?
Hypoglossal nerve
What innervates (sensory) the following:
- Skin on the lower eyelid
- Skin on eyebrow
- Skin on ala of nose
- Skin on chin?
- infratrochlear nerve from maxillary branch
- supraorbital nerve from ophthalmic nerve
- nasal branch of Infratrochlear nerve from maxilllary branch
- mental nerve from mandibular branch
What are the 4 special senses and the cranial nerves associated with the senses?
The nerves perceiving vision and smell do not enter the central nervous system at the brainstem, where do they enter instead?
What are the four cranial nerves carrying autonomic innervation?
III - Oculomotor nerve
VII - Facial nerve
IX - Glossopharyngeal nerve
X - Vagus nerve
What parasynthetic innervation does the oculomotor nerve have?
What parasynthetic innervation does the facial nerve have?
What parasympathetic innervation does the glossopharyngeal nerve have?
Parotid gland - produce saliva
What vertebrae make up the vertebral column?
33 vertebrae, 24 are moveable.
7 cervical, 12 thoracic, 5 lumbar, 5 sacrum and 4 coccyx
What are the functions of a vertebrae?
Weight bearing
Muscle attachment
Protection
What are the functions of the different colours shown?
What are the different layers around the spinal cord?
What is the epidural space?
The area of connective tissue and epidural fat between the bone and the dura mater. not present in the brain.
Where is the pia mater visible?
The denticulate ligaments when extend out of the spinal cord and stabilised the nerve roots
Where is the pia mater visible?
The denticulate ligaments when extend out of the spinal cord and stabilised the nerve roots
Where does the spinal cord terminate?
L1/L2 at the conus medularis
What is the caudal equina?
The cauda equina is a group of nerves and nerve roots stemming from the distal end of the spinal cord
‘Horses tail’
What is the filum terminale?
The filum terminale (FT) is a fibrous band that extends from the conus medullaris to the periosteum of the coccyx, helps to fixate the spinal cord
How bare peripheral nerves formed?
Dorsal (sensory) and ventral (motor) roots converge to become a mixed spinal nerve. They then divide into a ventral and dorsal ramus which both carry mixed information
Ventral- goes on to form plexuses and most anterior nerves, dorsal goes on to innervate back muscles
What is the epinuium?
Round the outside of the nerve is the connective tissue which is continued with arachnoid and dura
What is perinurium?
The perineurium is a protective sheath that surrounds a nerve fascicle.
What is the endoneurium?
Endoneurium is the intrafascicular connective tissue. It is composed of several nerve fibers making up a primary fascicle.
What are the missing labels for the diagram?
What is a neurolemma?
The thin sheath around a nerve axon (includes the surrounding cells such as schwann cells)
What are nerve cells myelinated by?
CNS= oliogodendrocytes
PNS= schwann cells
What are the different nerve plexuses?
Cervical (C1-4), brachial (C5-T1), Lumbar (T12-L5) and sacral plexus (L4-S4)
Where does the radial nerve innervate?
Posterior arm, forearm and hand
Where does the axillary nerve innervate?
Deltoid and the skin over the deltoid
Where does the musculotaneous nerve innervate?
Anterior compartment of arm, lateral aspect of forearm
Where does the median nerve innervate?
Most muscles of the forearm, few muscles in the hand and skin on palm
Where does the ulnar nerve innervate?
Some muscles in the forearm, most of the muscles in the hand and medial 1 and ½ digits of hand
What is the different roots of the brachial plexus?
What are the two types of autonomic motor fibre?
Parasympathetic and sympathetic
Where do the parasympathetic nerves arise from?
Arise from the cranial nerves or the sacral region
What cranial nerve provides lots of parasympathetic innervation to the body?
The vagus nerve
Where do the sympathetic nerves arrise from?
The thoracic level of spinal vertebrae
What is the root for the motor chain?
Has a pre-ganglionic and post-ganlionic neuron
Where are the autonomic ganglions located for parasympathetic nerves?
Some in the PNS, some in the target organ
How do sympathetic motor neurones get to their target tissue?
Leaves the ventral root, joins mixed spinal nerve. Shortly after that, the fibres exit in the white ramus communicantes and travels into the structure known as the sympathetic chain
- When it gets there, may meet post- ganglionic nerve, and be redistributed with the spinal nerves again via the grey ramus communicantes
- Other option- axon can travel up and down sympathetic chain, or exit via splanchnic nerves
What is the sympathetic chain?
The sympathetic chain is a ganglionated chain present bilaterally extending from the base of the skull to the coccyx.
What is the sympathetic chain?
The sympathetic chain is a ganglionated chain present bilaterally extending from the base of the skull to the coccyx.
What is a laminectomy?
where the posterior/dorsal part of the neural arch of the vertebral column has been removed to expose the dorsal surface of the spinal cord.
What are the denticulate ligaments?
They are triangular shaped ligaments that anchor the spinal cord along its length, at each side, to the dura mater.
What are the denticulate ligaments?
They are triangular shaped ligaments that anchor the spinal cord along its length, at each side, to the dura mater.
What are the missing labels?
How is the relationship of the meninges around the spinal cord to the overlying bony vertebral column different different to what you would expect to find for the meninges surrounding the brain?
There is an epidural / extradural space here (normally filled with epidural fat and small blood vessels) separating the dura from the vertebral column (see the image below of a cross section through the vertebral column). In contrast, the dura around the brain is firmly attached to the inner aspect of the skull vault (cranium)
What are the labels?
What are the normal contents of the lumbar cistern in a healthy, living individual?
Cauda equina (dorsal and ventral spinal nerve roots), filum terminale and CSF
What are the missing labels on the diagram of the brachial plexus?
What are the labels on the diagram?
How are the spinal nerves named?
There is 8 cervical spinal nerves, C1-7 are above and the rest below this point are below
What is a distinguishable feature of a thoracic part of the spinal cord?
The intermediate/lateral grey horn is a specific feature of the thoracic spinal cord, housing the cell bodies of pre-ganglionic sympathetic neurons
What type of neurotransmitter do the pre-ganglionic sympathetic neurons use?
Pre-ganglionic sympathetic neurons use the neurotransmitter acetylcholine, so they are referred to as cholinergic neurons
What type of neurotransmitter do most of the post-ganglionic sympathetic neurons use?
*most* post-ganglionic sympathetic neurons use the neurotransmitter norepinephrine/noradrenalin, so they are referred to as adrenergic neurons
What are the labels of the sympathetic division of the thoracic spinal cord?
How many pairs of thoracic splanchnic nerves are there, and what are they called?
3 pairs (Greater, Lesser and Least nerve on each side of the body)
Where are the thoracic splanchnic nerves passing to?
Greater splanchnic nerve goes to the coeliac ganglion
Lesser splanchnic nerve goes to the superior mesenteric ganglion
Least splanchnic nerve goes to the inferior mesenteric ganglion
Which functional type of neuron (e.g. using which specific neurotransmitter) makes up the parasympathetic contribution to the cranial nerves?
Cranial nerves contain axons of preganglionic parasympathetic neurons, which use the neurotransmitter acetylcholine. Hence, they are known as cholinergic neurons.
What are zygapophyseal/facet joints?
Also known as the zygapophyseal or apophyseal joint, is a synovial joint between the superior articular process of one vertebra and the inferior articular process of another
What are the labels?
What are the different coloured bones?
What are the different cranial fossa?
ANTERIOR, MIDDLE AND POSTERIOR
What are the missingl labels?
What are the missing labels?
What are the missing labels?
Which parts of the brain does the falx cerebri separate?
The falx cerebri separates the left and right cerebral hemispheres of the brain
Which parts of the brain does the tentorium cerebelli separate?
The tentorium cerebelli separates the occipital lobe (above) from the cerebellum (below)
What passes through the following: i) Foramen magnum ii) Carotid canal / Foramen lacerum iii) Optic canal
The optic canal transmits the optic nerve (and ophthalmic artery) – there are a pair of them
The carotid canal transmits the internal carotid artery – there are a pair of them
The foramen magnum transmits the spinal cord and vertebral arteries – there is only one
What are dural venous sinuses?
The dura mater is formed from two sheets of connective tissues, although in most places it looks like a single layer. In some places, there are channels located between these two sheets which are responsible for venous drainage of the cranium.
What are the missing labels?
What type of nerve fibres are most likely to be carried in the corpus callosum?
Commissural: these fibres are responsible for connecting one cerebral hemisphere to the other
What are the missing labels?
What are the differences in the brains between CT, MRI T1 and T2 scans?
What is the interventricular foramen also known as?
the Foramen of Monro
What is the name given to the specialised structures lining the ventricles that generate cerebrospinal fluid (CSF)?
The choroid plexus
How does CSF get into the subarachnoid space from the 4th ventricle?
Through one of 3 apertures (two lateral, and one median; also known as the foramen of Luschka and Magendie respectively)
Where is CSF resorbed back into the general circulation
Via arachnoid granulations (little sponge-like structures) located around the superior sagittal sinus (one of the dural venous sinuses)
What are the missing labels?
What are the missing labels?
What is the lumbar cistern?
While the spinal cord ends at the level of the 1st/2nd lumbar (L1/2) vertebrae in the adult, the dura and arachnoid maters extend down to the level of the sacrum (inserting at the level of S2). As a result, there is an extension of the subarachnoid space beyond the termination of the spinal cord, down to the end of the meninges at S2. This space is called the lumbar cistern and is the site used for lumbar punctures to sample CSF
How many pairs are there in each region of the spinal cord?
Cervical: 8 pairs
Thoracic: 12 pairs
Lumbar: 5 pairs
Sacral: 5 pairs
Coccygeal: 1 pair
31 in total
What are the missing labels?
What are the missing labels?
What is the order of the dorsal column pathway?
Peripheral receptor – DRG – Fasciculus cuneatus/gracillis – nucleus cuneatus/gracillis – internal arcuate fibres – medial lemniscus – VPL thalamus – internal capsule - corona radiata – post central gyrus
What is the order of the spinothalamic pathway?
Peripheral receptor – DRG – dorsal horn – ventral white commissure – spinothalamic tract of spinal cord –spinal lemniscus – VPL thalamus – internal capsule - corona radiata – post central gyrus
What are the missing labels of the medulla?
What are the missing labels of the pons?
What are the missing labels?
What are the differences in the spinal and medial lemniscus?
Medial= carries dorsal column
Spinal= carries spinothalamic
What are the missing labels of the brain stem?
What are the missing labels of the brain stem (posterior)
Where do neurons carrying sensory information for the head and neck, and the rest of the body, synapse?
Head and neck
- Ventroposteriomedial (VPM) nucleus of the thalamus
Rest of the body
- Ventroposteriolateral (VPL) nucleus of the thalamus
What areas of grey matter form the boundaries of the internal capsule on a horizontal section?
Caudate nucleus, Lentiform nucleus, Thalamus
What are the missing labels?
What are the missing labels?
What are the missing labels?
What are the missing labels?
What is the principal arterial blood supply to the region of primary somatosensory cortex receiving information from the lower limb?
Anterior cerebral artery
What is the principal arterial blood supply to the region of primary somatosensory cortex receiving information from the head?
Middle cerebral artery
The pictures below show an H and E stained DRG section. What are the large pink cells which you can see?
The cell bodies of first order sensory neurons
What are the blue arrows pointing to?
Dorsal root ganglion
What are the key anatomical landmarks in the body region associated with the following key dermatomes:
C2 / C3 dermatome C6 dermatome T4 dermatome T10 dermatome L4 dermatome
What is this in the pons?
Trigeminal nerve
Where do the cell bodies of most sensory neurons pertaining to the trigeminal nerve lie?
lie in the trigeminal ganglion, a structure found outwith the brain stem. These neurons will synapse in one of the following sensory nuclei of the brainstem:
- mesencephalic nucleus
- chief sensory nucleus
- nucleus of the spinal tract of the trigeminal.
What does the spinocerebellar pathway carry?
The spinocerebellar pathway carries information related to the subconscious control of posture and coordination of movement
What is the route of the spinocerebellar pathway?
There are 2 neurons in this pathway. As in other sensory pathways, the cell body of the first order neuron is in the DRG (you will see these at station 3). The cell bodies of second order neurons mostly lie in the dorsal grey horn of the spinal cord.
There are 2 principle tracts relating to the spinocerebellar pathway:
dorsal spinocerebellar tract - axons do not decussate (cross)
ventral spinocerebellar tract – axons do decussate (cross)
The dorsal spinocerebellar tract ascend ipsilaterally and enters the cerebellum through the inferior cerebellar peduncle. The axons of the ventral spinocerebellar tract ascend contralaterally and then decussate back in the brainstem before entering the cerebellum through the superior cerebellar peduncle.
What are the missing labels?
Where are the corticospinal and corticobulbar fibres located in the internal capsule?
Corticospinal and corticobulbar fibres are both located in the posterior limb of the internal capsule. The corticospinal fibres are nearer the retrolenticular region, corticobulbar fibres are nearer the genu.
What are the missing labels?
On what cerebral hemisphere is broca’s area located?
Broca’s area is located predominantly in the dominant cerebral hemisphere, usually the left one. Ablating this area on the non-dominant hemisphere has little or no effect on speech.
What is the route of the corticospinal tract?
Primary motor cortex -> Corona radiata -> Internal capsule -> Crus cerebri -> Pyramid -> Decussation of the pyramid -> Lateral corticospinal tract -> Ventral horn
Where are the cell bodies of lower motor neurons located?
In the ventral grey horn of the spinal cord. Their axons exit the spinal cord in the ventral root, and merge with the dorsal root to form a mixed spinal nerve.
What happens to the majority of descending cortico-spinal motor axons at the decussation of the pyramids?
They cross (decussate) to the contralateral side
What is the main differences between the lateral and ventral corticospinal tracts?
Fibres in the lateral tract decussated in the medulla; fibres in the ventral tract are ipsilateral and will decussate in the spinal cord close to the vertebral level where their target lower motor neurons are located
What function does the corticospinal tract have?
Voluntary motor activity
What pathway is this and what are the missing labels?
Corticospinal tract
What are the missing labels on this cross section of a spinal cord?
What is the role of the basal ganglia?
The basal ganglia are a group of sub-cortical nuclei with extensive connections to the cortex and thalamus. They perform many roles in the CNS, but one of the main ones is to act as a ‘checking system’ for motor activity
They can be considered to facilitate wanted movements and eliminate inappropriate movements
What is inolved in the direct and indirect pathways of the basal ganglia?
What is the striatum formed of?
The caudate nucleus and putamen, although anatomically distinct, form a single functional unit known as the neostriatum (or just striatum for short
What is the shape of the caudate nucelus and where is it located?
. Caudate means ‘tail like’ and, together with the putamen, forms a tadpole-like shape which follows the curvature of the lateral ventricle
What does the substantia niagra use as a neurotransmitter?
Dopamine
What are the 4 important involuntary/ extrapyramidal motor tracts?
Four important extrapyramidal tracts are:
- Rubrospinal – UMN cell bodies in the red nucleus
- Vestibulospinal – UMN cell bodies in the vestibular nuclei
- Tectospinal – UMN cell bodies in the superior colliculus
- Reticulospinal – UMN cell bodies in the reticular formatio
What do the extrapyramdial pathways recieve information and activate?
What are the missing labels?
What are the missing labels?
What are the missing labels?
What are the normal contents of the lumbar cistern in a healthy, living individual?
Cauda equina (dorsal and ventral spinal nerve roots), filum terminale and CSF – the lumbar cistern is the region you can safely sample CSF from using a lumbar puncture (a.k.a. spinal tap) procedure.
How is the dura different in the brain to the spinal cord?
There is an epidural / extradural space in the spinal column (normally filled with epidural fat and small blood vessels) separating the dura from the vertebral column. In contrast, the dura around the brain is firmly attached to the inner aspect of the skull vault (cranium)
What are the missing labels?
How do the spinal nerves relate to the vertebrae?
the C nerves emerges above the corresponding vertebra; from T1 onwards, the spinal nerves emerge below their corresponding vertebra
Where does the brachial plexus arise from?
C5 to T1
What divisions is the brachial plexus split into?
5 roots > 3 trunks > 6 divisions > 3 cords and 5 nerves
What is the structure of the brachial plexus?
What are the missing labels?
What are the missing labels?
What are the 3 main nerves that emerge from the lumbrosacral plexus?
the femoral nerve, the obturator nerve and the sciatic nerve.
What are the missing labels?
What are the missing labels?
What are the missing labels?
What are the missing labels?
Where are the zygapophyseal (a.k.a. facet) joints?
Where in the spinal cord do the sympathetic and parasympathetic nerves arise from?
Whereas the sympathetic division of the autonomic nervous system emerges from the thoracic regions of spinal cord, the parasympathetic division arises largely from cranial nerves III, VII, IX and X, supported by a small contribution from the bottom (sacral) end of the spinal cord (via the pelvic splanchnic nerves, coming from S2-S4).
Which functional type of neuron (e.g. using which specific neurotransmitter) makes up the parasympathetic contribution to the cranial nerves?
Cranial nerves contain axons of preganglionic parasympathetic neurons, which use the neurotransmitter acetylcholine. Hence, they are known as cholinergic neurons.
What cranial nerves contain parasympathetic fibres?
III – Oculomotor nerve
VII – Facial nerve
IX – Glossopharyngeal nerve
X – Vagus nerve
Identify the numbered structures on the diagram below
What happens to preganglionic sympathetic nerves once they have entered the sympathetic chain?
They can either synapse straight away, ascend and then synapse, descend and then synapse, or pass straight through by entering a thoracic splanchnic nerve
How many pairs of thoracic splanchnic nerves are there, and what are they called?
3 pairs (Greater, Lesser and Least nerve on each side of the body)
Where are the thoracic splanchnic nerves passing to?
Greater splanchnic nerve goes to the coeliac ganglion
Lesser splanchnic nerve goes to the superior mesenteric ganglion
Least splanchnic nerve goes to the inferior mesenteric ganglion
What are the missing lables?
What are the missing labels?
What does the the greater splanchic nerve look like?
Where is the ventral/anterior white comminsure?
What is the lateral grey horn?
The lateral grey column is primarily involved with activity in the sympathetic division of the autonomic motor system. It projects to the side as a triangular field in the thoracic and upper lumbar regions
What neurotransmitters do pre and post ganglionic sympathetic neurones use?
Pre-ganglionic sympathetic neurons use the neurotransmitter acetylcholine, so they are referred to as cholinergic neurons
most post-ganglionic sympathetic neurons use the neurotransmitter norepinephrine/noradrenalin, so they are referred to as adrenergic neurons
What are the missing labels?
What are the missing labels?
What nerve(s) pass through the optic canal?
Optic nerve
What nerve(s) pass through the superior orbital fissue?
Oculomotor
Trochlear
Trigeminal: Ophthalmic
Abducens
What nerve(s) pass through the foramen routundum?
Trigeminal: Maxillary
What nerve(s) pass through the foramen ovale
Trigeminal: Mandibular
What nerve(s) pass through the internal acoustic meatus?
Facial
Vestibulocochlear
What nerve(s) pass through the hypoglossal canal?
Hypoglossal
What nerve(s) pass through the jugular foramen?
Glossopharyngeal
Vagus
Accessory
What innervates this muscle and what is it?
Masseter
Mandibular nerve (Trigeminal)
What are the intrinsic tongue muscles innervated by?
Hypoglossal nerve
What innervates orbicularis oris?
Facial nerve
What are the missing labels?
What innervates the Superior pharyngeal constrictor?
Vagus nerve
What innervates the trapezius muscles?
Accessory nerve
What nerve supplies muscles of facial expression?
Facial nerve
Which muscle primarily is responsible for each of the eye movements shown?
What are the missing labels?
What cranial nerve provides innervation to the extraocular muscles?
Lateral rectus = CNVI, superior oblique = CNIV, all others = CNIII
What are the three cranial nerves that contribute to general sensation at the ear?
One cranial nerve perceives general sensory information from the pharynx making up the afferent limb of the gag reflex. What nerve is this?
Glossopharyngeal
What is the skin on lower eyelid innervated by?
Maxillary nerve
What is the skin on lower eyelid innervated by?
Maxillary nerve
What is the skin on the eyebrow innervated by?
Opthalmic nerve
What is the skin on the ala of the nose innervated by?
Maxillary nerve
What is the skin on the chin innervated by?
Mandibular nerve
What cranial nerves are responsible for perceiving stimuli associated with these senses?
The nerves perceiving vision and smell do not enter the central nervous system at the brainstem, where do they enter instead?
Olfactory- Temporal lobe (uncus)
Optic- Optic chiasm
What is Bitemporal hemianopia and what causes it?
Bitemporal hemianopia is the loss of vision in half of the visual field, specifically the temporal half.
Compression of optic chiasm
What are the four cranial nerves carrying autonomic innervation?
III - Oculomotor nerve
VII - Facial nerve
IX - Glossopharyngeal nerve
X - Vagus nerve
What are the target tissues and function at the tissues of the following:
Where do the cranial nerves arise from?
The first two nerves (olfactory and optic) arise from the cerebrum
Midbrain – the trochlear nerve (IV) comes from the posterior side of the midbrain.
Midbrain-pontine junction – oculomotor (III).
Pons – trigeminal (V).
Pontine-medulla junction – abducens, facial, vestibulocochlear (VI-VIII).
Medulla oblongata
Posterior to the olive: glossopharyngeal, vagus, accessory (IX-XI). Anterior to the olive: hypoglossal (XII).
What are the cranial nerves?
What are the missing labels?
What are the missing labels?
