Neuroanatomy Flashcards
What makes up the CNS
The brain and the spinal cord
What makes up the PNS
The peripheral nerves
12 pairs of cranial nerves and 31 pairs of spinal nerves and their branches
Where does the CNS become the PNS
As the spinal nerve roots leave the spinal cord
How does the nervous system develop
Begins as the neural tube
Brain is hollow and fluid filled
Early on 3 swellings form
The bottom 2 will further divide to give 5 ‘vesicles in the neural tube
Each section will become a specific section of the brain
Name the 5 major embryonic divisions of the brain
Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon
What does the telencephalon go on to form
the cerebral hemispheres
This expands massively in human development
What does the diencephalon go on to form
The thalamus and the hypothalamus
What does the mesencephalon go on to form
The midbrain
What does the metencephalon go on to form
The pons and the cerebellum
What does the myelencephalon go on to form
The medulla oblongata
What sections make up the brainstem
The midbrain
Pons
Medulla
What are the functions of the neurons
They receive information, integrate it and then transmit it in the form of the electrical impulses
Can pass to it onto other neurons or effector cells
Describe the structure of neurons
They have a cell body that contains the nucleus and cellular apparatus
They have numerous dendrites to receive info
One axon will transmit info - can be extremely long
Does the brain contain connective tissues
Nope
A small amount comes in with the blood vessels but doesn’t count
What are the main types of glial cells
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
What are the functions of astrocytes
Roles in supporting the brain, maintaining the BBB and homeostasis
What is the structure of an astrocyte
Star shaped cells
Multiple processes
What is the function of the oligodendrocytes
Produce myelin in the CNS
They reach out to nearby axons with multiple branches and wrap layers of cell membrane around it
What is the function of the myelin sheath
Increases rate of signal transmission
Allows signals to jump along the axon from node to node (node is an unmyelinated area)
What is the function of microglia
Immune cells - immune monitoring and antigen presentation
Similar to macrophages but they stay in the CNS
What is the function of the ependymal cells
Ciliated cuboidal/columnar epithelium that lines the ventricles.
They produce the CSF
What is the difference between the gyri and sulci
Gyri are the bits that stick out and the sulci are the indentations
What are the deepest sulci called
Fissures
There are around finger depth
What are the two types of brain tissue
Grey matter and white matter
Describe the grey matter
covers the outside of the brain
Contains the neuron cell bodies and lots of glial cells
There is also some deep grey areas within the centre of the brain
Describe the white matter
forms the core
There are no nerve cell bodies in here but the axons extend into it
Lots of glial cells
Describe the organisation of grey and white matter in the spinal cord
Grey is on the inside in a H like shape - with posterior/dorsal and anterior/ventral horns
White matter organised in columns around it - posterior/dorsal, lateral and anterior/ventral
What is found at the precentral gyrus
Primary motor area
Found in front of the large central sulcus
What is found at the postcentral gyrus
The somatosensory area of the brain
Found behind the central sulcus
Is the thalamus a grey or white structure
Grey
What does the calcarine sulcus mark the edge of
The visual cortex
What is the corpus callosum
A band of white matter that separates the 2 hemispheres
Connecting point between them so millions of axons cross here
The central sulcus forms the boundary between which lobes
Frontal and parietal
Where is the frontal lobe found
anterior to the central sulcus and superior to the lateral sulcus.
Where is the parietal lobe found
posterior to the central sulcus, superior to the lateral sulcus and anterior to the parieto-occipital sulcus
Where is the occipital lobe found
posterior to a line from the parieto-occipital sulcus to the preocciptial notch.
Where is the temporal lobe found
inferior to the lateral sulcus and anterior to the parieto-occipital sulcus line
What is the insular lobe
Hidden 5th lobe of the brain – under the temporal
Very important – involved in pain
Close to brain stem
What are the layers of the meninges
Dura mater
Arachnoid mater
(subarachnoid space with CSF)
Pia mater
What connects the lateral ventricles to the 3rd
Intraventricular foramen
What connects the 3rd and 4th ventricles
Cerebral aqueduct
How does CSF leave the 4th ventricles
Through the apertures
Enters the spinal cord and subarachnoid space
Describe the enteric nervous system
Found in digestive system from oesophagus to rectum
Neurons found largely in two plexuses in the walls of the gut (myenteric and submucosal)
Contains same number of neurons as spinal cord
Describe the blood supply to the brain
Comes from the vertebral arteries which become the basilar artery at the pons
This joins the 2 internal carotids to form the circle of Willis
The anterior and middle cerebral arteries arise from the carotids
The posterior comes from the basilar
Describe the venous drainage of the brain
It drains into a system of dural venous sinuses - intercavernous and cavernous
They then drain into the internal jugular vein through the jugular foramen
What is a ganglion
Small group of neuron bodies in the PNS
What are the two main types of neurones
Unipolar and multipolar
Describe multipolar neurones
Those with 2 or more dendrites
Most common - includes all motor neurons for skeletal muscle and ANS
Cell body is found in the CNS
Describe unipolar neurones
Do technically have a double process - so also called pseudounipolar
Cell body is in the PNS
Sensory neurones
What forms a nerve
Collections of axons surrounded by connective tissue and blood vessels
What is a single modality nerve
Only carries one type of fibre
e.g. motor, sensory, sympathetic etc
What is a mixed modality nerve
where several types of axon lie together in one nerve
Where are the spinal nerves found
ONLY in the intervertebral foramina
What do the spinal nerves connect with
Structures of the soma via the rami
The spinal cord segment of the same level via the roots and rootlets
The roots and rootlets are mixed modality - TRUE OR FALSE
FALSE
Roots/rootlets – single modality
Spinal nerve – mixed modality
Describe the path of sensory axons
pass from the spinal nerve into the posterior root then into the posterior rootlets then into the posterior horn of the spinal cord
Describe the path of motor axons
They pass from the anterior horn of the spinal cord into the anterior rootlets then into the anterior root then into the spinal nerve
What does each spinal nerve pair supply
They provide a specific body segment with general sensory to all structures, somatic motor to all skeletal muscles and a sympathetic nerve supply to the skin and smooth muscle of arterioles
What is a dermatome
Area of skin supplied with sensory innervation from a single spinal nerve
Also supplies some deeper structures
What is a myotome
The group of skeletal muscles supplied by one spinal nerve - motor innervation
May be the same as the overlying dermatome but not always
What are the thoracic dermatome landmarks
T4 segment is the nipple line
T10 segment is the umbilicus
Which nerves supply the dermatomes of the upper limb
C5-T1
Which nerves supply the dermatomes of the lower limb, gluteal and perineum
L2- Co1
What forms the cervical plexus and what does it supple
C1-C4 anterior rami
Supplies the posterior scalp, neck and diaphragm
What forms the brachial plexus and what does it supply
C5-T1 anterior rami
Upper limb
What forms the lumbar plexus and what does it supply
L1-L4 anterior rami
Supplies the lower limb
What forms the sacral plexus and what does it supply
L5-S4 anterior rami
Supplies the lower limb, gluteal region and perineum
Which vertebral levels do the sympathetic nerves arise from
the lateral horns of T1 - L2
Pass out through the anterior rootlets/roots
Describe the path of sympathetic fibres that supply the heart
Presynaptic axons synapse in T1 or cervical paravertebral ganglia
Postsynaptic axons pass in cardiopulmonary splanchnic nerves to the SA & AV nodes & the myocardium
Describe the path of sympathetic fibres that supply the lungs
Presynaptic axons synapse in upper thoracic paravertebral ganglia
Postsynaptic axons pass in cardiopulmonary splanchnic nerves to the bronchiolar smooth muscle & mucous glands
Describe the path of sympathetic fibres that supply the abdominopelvic organs
Presynaptic axons synapse in one of the prevertebral ganglia: coeliac ganglion for the foregut, aorticorenal for kidneys, superior mesenteric for midgut and inferior mesenteric for hindgut and pelvis
Where do the parasympathetic nerves originate from
Presynaptic axons have cranial sacral outflow - CN III, VII, IX and X and the sacral spinal nerves
What do parasympathetic fibres from the vagus nerve supply
Organs of the neck, chest and abdomen as far as the mid-gut
Where do the parasympathetic fibres for the eye synapse
Ciliary ganglion
Where do the parasympathetic fibres for the lacrimal and salivary glands synapse
Parasympathetic ganglia in the head
What do parasympathetic fibres from the sacral spinal nerves supply
Hindgut, pelvis and perineum
What causes Horner’s syndrome
Compression of the cervical parts of the sympathetic trunk
This decreases sympathetic innervation to the head and neck
What are the symptoms of Horner’s syndrome
Miosis - pinpoint pupil
Ptosis - droopy eyelid
Reduced sweating (anhydrosis)
Increased warmth and redness - due to vasodilation
What are the spinal enlargements
Enlargements in the spinal cord that supply the limbs
Therefore there are 2 - cervical and lumbar
What forms a spinal nerve root
A series of rootlets emerge from either the dorsal or ventral part of the spinal cord
They come together to form either an anterior or posterior root
What type of fibres do the anterior roots carry
Motor fibres
Travel away from the spinal cord
What type of fibres do the posterior roots carry
Sensory fibres
Bring information into the spinal cord
Describe the path of the spinal roots
Pass through the subarachnoid space until they reach the appropriate intervertebral foramina
As the posterior one passes through it is enlarged by the dorsal root ganglion
Will go on to fuse and become the spinal nerve for that level
What is the tip of the spinal cord called
Conus medullaris
What is the filum terminals
A cord like continuation of the conus medullaris which anchors the spinal cord to the spine (at the coccyx)
What is the denticulate ligament
Ribbon of tissue on the lateral aspect of the spinal cord
Formed by pia and arachnoid tissue
Suspends the cord within the canal
The spinal cord is also surrounded by the meninges - TRUE OR FALSE
TRUE
It is continuous with the cranial meninges and includes all 3 layers
What comprises the grey matter in the spinal cord
Neuronal soma, cell processes, synapses, glia and blood vessels.
What comprises the white matter in the spinal cord
Longitudinally oriented nerve fibres (axons), glial cells and blood vessels
The spinal cord has a canal in the centre - TRUE OR FALSE
TRUE
Its a very small canal that extends the entire length
It is continuous with the 4th ventricle and so contains CSF
How is the white matter of the spinal cord organised
Into the anterior, lateral and posterior columns
There is an extra horn of grey matter at which spinal levels
From T1 to L2
This lateral horn contains the preganglionic sympathetic neurons
Describe the arterial supply to the spinal cord
3 main sources:
3 major longitudinal arteries run the length (1 anterior and 2 posterior)
Segmental arteries that come from the vertebral, intercostal and lumbar ones
Radicular arteries which travel along the roots
what happens if the blood supply to the spinal cord is occluded
Spinal cord infarction
Describe the venous drainage of the spinal cord
Follows similar patterns to arteries as there are longitudinal and segmental veins
Plexuses are found in the epidural space
What is the epidural space
The space between the dura and the bone in the spinal canal
It contains adipose tissue and epidural venous plexuses
Right side of the brain receives sensation from the right side of the body - True or False
FALSE
sensory fibres cross at the midline so brain receives sensation from the opposite side of the body
What happens to white matter as you travel down the cord
Less and less white matter as you travel down the cord as the fibres start leaving to supply the appropriate areas
What are the descending spinal cord tracts responsible for
Motor functions
What are the ascending spinal cord tracts responsible for
Sensory function
Describe the path and function of the dorsal column
Carries sensation of fine touch and proprioception up to the brain
They fibres travel up the cord and synapse in the medulla at the nucleus gracillus
The second order neuron crosses the midline to the pons where it synapses again in the thalamus
Third order leaves thalamus and goes into the cerebrum
What is the function of the spinothalamic tract
Transmits pain, temperature and deep pressure to the brain
Describe the path of the spinothalamic tract
1st order arises from sensory receptors in periphery which enter the cord and synapse at tip of the dorsal horn
The second neurone crosses to the white matter on the opposite side where it then travels ups the cord to the brain where it synapses again at the thalamus
The third neurone takes this to the primary sensory cortex
What is another name for the spinothalamic tract
Antero-lateral tract
What are the divisions of the dorsal column
Cutaneous and gracilis
The gracilis carries the information from the leg (graceful)
The cutaneous carries the arm information
What is the function of the corticospinal tract
Control of fine, precise movement
Conscious and voluntary
Particularly in the distal limb - e.g. fingers
What is another name for the corticospinal tract
Pyramidal tract
Where do the fibres of the corticospinal tract cross
Most cross at the decussation of the pyramids in the medulla
This forms the lateral CST
The ones that don’t cross form the ventral CST which will cross at the segment that it leaves the spinal column
List the extra-pyramidal tracts
Tectospinal
Reticulospinal
Rubrospinal
Vestibulospinal
What is the function of the tectospinal tract
Thought to coordinate head and neck movement in response to visual stimuli.
Describe the path of the tectospinal tract
Begins in the tectum of the midbrain
This area gets input from the optic nerves
Travels down to the cervical region and terminates
List the pyramidal tracts
Corticospinal
Corticobulbar
What is the function of the corticobulbar tract
Help carry motor signals to the muscles of the face and neck
Supplies the cranial nerves nuclei with motor fibres
Describe the path of the corticobulbar tracts
Arise in lateral aspect of primary motor cortex
Pass through internal capsule of brainstem
Terminate in the motor nuclei of the cranial nerves where they synapse with motor neurons to carry the signal
What is the function of the vestibulospinal tracts
Control balance and posture by innervating the anti-gravity muscles
(arm flexors, leg extensors)
Control head and neck movements
Describe the path of the vestibulospinal tracts
They arise from the vestibular nuclei of pons and medulla - medial and lateral
The tracts travel down the spinal cord where they stay ipsilateral
medial tract stops ay cervical cord to control head and neck movement
Lateral goes down to lumbar to control posture
What is the difference between the lateral and medial reticulospinal tracts
Lateral arises in medulla, inhibits voluntary movement and reduces muscle tone
Medial tract arises from the pons, facilitates voluntary movements and increases muscle tone
What is the function of the rubrospinal tract
Thought to play a role in fine hand movement
Controls limb flexors (excites) and inhibits extensors
Describe the path of the rubrospinal tract
Originates in the red nucleus in the midbrain
As they emerge from here, they cross and descend the spinal cord
Terminate in the ventral horn
Contralateral innervation
What is Brown-Sequard syndrome
Occurs after hemi-section of the spinal cord
Occurs with penetrating wounds
Interrupts 1 side of the tracts
Will get weakness and paralysis on same side as injury
Loss of fine sensation on same side as injury
Opposite side will see a reduction in pain/temp
Describe the gross anatomy of the cerebellum
Has 3 lobes: anterior, posterior (largest) and flocculonodular lobe (has ‘ears’)
Sits in the posterior cranial fossa under the tentorium cerebelli
Attached to brain stem via 3 stumps of white matter (peduncles) which have fibres that carry info in and out
what are the gyri called in the cerebellum
Folia
What are the deep cerebellar nuclei
Areas of grey matter embedded deep within the white matter core
Important for communication
What are the 3 layers of the cerebellum
Molecular layer on outside – huge number of synapses
Purkinje cell layer in the middle (giant cells)
Granule cell layer on inside (stuffed full of neurones)
From where does the cerebellum receive afferent projections
Spinal cord - from somatic proprioceptors and pressure receptors
The cerebral cortex
Vestibular apparatus
Describe the path and function of the efferent projections of the cerebellum
Axons from the Purkinje cells are the only output
Synapse with neurons of the deep cerebellar nuclei
The fibres then cross and synapse in the thalamus before travelling to the motor cortex
They contribute to coordinating the functions of all the motor tracts
Cerebral hemispheres influence the contralateral side of the body - true or false
FALSE
Influence the ipsilateral side so will cause symptoms in the same side
What effect would a midline cerebellar lesion have
Disturbance of postural control
Person will fall when standing or sitting but will still have coordination in limbs
What effect would a unilateral cerebellar lesion have
Disturbance of coordination in the limbs
Tremor, unsteady gait
NO weakness or sensory loss
What effect would a bilateral cerebellar lesion/dysfunction have
Slowed, slurred speech
Bilateral loss of coordination in the limbs
Cerebral ataxia - wide based, staggering gait
What are the functions of the basal ganglia
Facilitates purposeful movement
Inhibits unwanted movement
Role in posture and muscle tone
Acts as an amplifier of small amounts of activity within the motor cortex - direct
A second pathway will dampen signals in the thalamus to reduce cortex response - indirect
Name the 5 area that make up the basal ganglia
Caudate nucleus Putamen Globus pallidus Subthalamic nucleus Substantia nigra
Which areas make up the striatum
Caudate nucleus
Putamen
Which areas make up the corpus striatum
Caudate nucleus
Putamen -
Globus pallidus
Which areas make up the lenticular nucleus
Putamen
Globus pallidus
(looks like a lentil)
What are the basal ganglia
A number of masses of grey matter located near the base of each cerebral hemisphere
Where is the caudate nucleus found
In the floor of the lateral ventricles - follows the horns
What is released from the substantia nigra
Dopamine
Which condition is a result of reduced dopamine secretion from the substantia nigra
Parkinson’s disease
Unilateral lesions in the basal ganglia will affect the opposite side of the body - true or false
TRUE
What are the signs and symptoms of a basal ganglia lesion
Change in muscle tone Dyskinesia - abnormal or involuntary movement Tremor Chorea - rapid, asymmetrical movement Myoclonus - muscle jerks
What causes Huntington’s Disease
Autosomal dominant gene
Leads to progressive degeneration of the basal ganglia and cerebral cortex
Where do the motor components of a cranial nerve come from
They are associated with motor nuclei
These are groups of efferent nerves that send axons into the cranial nerve
Where do the sensory components of a cranial nerve come from
Associated with sensory nuclei
These are groups of nerve cells upon which the sensory neurons of the cranial nerves synapse
Where is the olfactory nerve found
Fibres pass through the cribriform plate up to the bulb
Passes straight back to the olfactory cortex
Only sensory nerve that doesn’t go to the thalamus first
Which type of cranial nerve has its nuclei in the midline
Motor ones
Sensory ones are further out
Which cranial nerve arises from the superior colliculus
Oculomotor - CNIII
Provides somatic motor innervation to eye muscles
Parasympathetic innervation to the ciliary body
Which cranial nerve arises from the inferior colliculus
Trochlear - CNIV
Innervates superior oblique
Which cranial nerve is the only one to exit posteriorly
Trochlear
It moves backwards then rotates out the way
Which cranial nerve arises from the abducens nucleus
Abducens - CNVI
Where does the hypoglossal nerve arise from
A large motor nucleus that starts at pons and goes down through medulla
Which cranial nerves arise from the midline
CNIII - Oculomotor
CNIV - Trochlear
CNVI - Abducens
CNXII - Hypoglossal
Which of the cranial nerves actually arises from the spinal cord
CNXI - spinal accessory nerve
Comes from the accessory nucleus in the ventral horn of the cervical spinal cord
Which cranial nerve sensory nuclei is the trigeminal nerve associated with
Spinal nucleus - in spinal cord, linked to ST tract and receives pain and temperature Pontine Trigeminal nucleus - found in pons and receives touch and vibration
Mesencephalic nucleus - receives proprioception from oral cavity
What are the functions of the facial nerve
Motor to muscles of facial expression and stapedius
Parasymp to pterygopalatine and submandibular ganglia
Taste to anterior 2/3 of tongue
What are the functions of the glossopharyngeal nerve
Tactile sense, pain and temp from posterior tongue and pharynx
Taste to posterior 1/3
Parasymp to the otic ganglion - parotids
Motor to the stylopharyngeus
What are the functions of the vagus nerve
Tactile sense, pain and temp from pharynx, larynx, trachea, oesophagus and abdominal organs
Taste - epiglottis
Parasymp to thoracic and abdominal viscera
Which nuclei is the facial nerve associated with
Facial motor nucleus - motor fibres from here
Salivatory nucleus - submandibular ganglion
Solitary nucleus - sensory and taste
Some sensory fibres go to trigeminal spinal nucleus
Which nuclei is the glossopharyngeal nerve associated with
Solitary nucleus - receives taste fibres
Spinal trigeminal nucleus - small region of sensation
Nucleus ambiguous - controls stylopharygeus for swallowing
Inferior salivatory nucleus
Which nuclei is the vagus nerve associated with
Dorsal motor nucleus - parsymp outflow
Solitary nucleus - taste
Spinal trigeminal - pain and small sensory area
Nucleus ambiguous - motor
Where is the solitary nucleus found
Starts in the pons and goes down to the medulla
V-shaped
What is the function of the solitary nucleus
Taste and general visceral sensation
Associated with CN VII, IX and X
Where do the parasympathetic efferents to CN originate
Input is mainly from the hypothalamus which sends efferents to the preganglionic autonomic neurons
What is the reticular formation
A network of loosely linked nuclei in the brainstem
It integrates cranial reflexes, conducts and modulates pain, influences voluntary movement and regulates autonomic activity
It integrates respiration and sleep - if this fails you die
Describe the auditory pathway
Starts in the organ of corti
Neurons go the spiral ganglion
Then pass to the cochlear nuclei - ventral and dorsal
Some fibres will decussate here whilst other remain on the same side - bilateral input from here
Neurons that go from the ventral will go through the superior olivary nucleus before travelling up the lateral lemniscus
Those from dorsal go straight to the lateral lemniscus
Both sets synapse in the inferior colliculus
From there they go into the thalamus and enter the medial geniculate nucleus
Travel from here to the cortex
The auditory pathway has bilateral input - true or false
TRUE
Some fibres cross and other don’t - input comes from both sides
If deaf in one ear it cannot be an issue in the brain
What structure allows us to localise sound
Olivary nucleus
It does this by comparing the timing of sound reaching the left and right ears
Where is the primary auditory cortex found
The superior aspect of the temporal lobe
Describe how the auditory cortex is organised
Tonotopically
Fibres relaying low frequency sounds end in the anterolateral region of the cortex whilst high frequency end in the posteromedial part
How is the cochlea organised
Tonotopically
Tip of the cochlea responds best to low frequency and the base to high frequency
What is aphasia
The inability to use language
Different types due to inability to produce language yourself or unable to comprehend it
What happens if there is damage to Wernicke’s area
Patient’s cannot comprehend language
This can present with words out of order or meaningless words
Called Wernicke’s, sensory or receptive aphasia
What happens if there is damage to Broca’s area
Patient will struggle to produce language (e.g. will only say a few out of a sentence)
Can still understand language
Called Broca’s, motor or expressive aphasia
How are vestibular signals created
Fluid movement in the semi-circular canals of the inner ear
This moves hair cells which creates the signal
Describe the path of vestibular signals
Fibres gather in the vestibular ganglion - swelling in the vestibular body
Then synapses in vestibular nuclei either side of the brainstem
Signals are then delivered to many areas of the cortex and cerebellum as they have many functions
Describe the path of the optic nerve
Travel back from the eye
Cross at the chiasm
The tract first synapses at the lateral geniculate nucleus in the thalamus
The 2nd order neurones project back to the occipital lobe
The ones carrying the upper half of the visual field have to loop around the lateral ventricle in Meyer’s loop
Describe how signals from the optic nerves cross
The fibres cross at the chiasm
Therefore each tract, lateral geniculate nucleus, optic radiation and visual cortex deals with the contralateral visual field
What is the role of visual input to the superior colliculi
Branches from the optic tracts supply it with information to help aim our eyes
Responsible from some visual reflexes
Describe the locations of the optic radiations
Lower visual field is projected to the gyrus superior to the calcarine sulcus
Upper visual field is projected to the inferior
Describe the macula’s designated area of the cortex
proportionally much larger than the area of the eye dedicated to the macula
Larger cortex area means it gives higher acuity
How does the visual cortex influence eye movement
Provides for movements in response to visual stimuli
Tracking movements - smooth sweeping movements
What is the difference between eye movements controlled by visual cortex and the frontal eye fields
Visual cortex controls tracking movements which are smooth and sweeping
Frontal fields are movements of commands - jumpy
Which nucleus is involved in the pupillary light reflex
The EW nucleus
It activates neurones in both eyes to cause consensual reflex
Which nucleus is involved in the accommodation reflex
The EW and oculomotor reflex
Both are needed to converge gaze and constrict pupils
Do people have a dominant hemisphere
To some extent
For some higher functions one side will take the lead
E.g. most right handed people will be left hemisphere dominant for language
What are association fibres
Fibres in the white matter that connect cortical sites in the same hemisphere
What are the commissural fibres
Fibres in the white matter that connect one hemisphere to the other - usually between areas of similar function
What are projection fibres
Fibres in the white matter that connect the hemispheres to deeper structures such as the thalamus, brain stem and spinal cord
What controls the corticospinal and rubrospinal tracts
Cerebral cortex
Called the lateral pathways
Describe the path of the corticospinal tract
Cell bodies found in the motor cortex and parietal
Fibres travel through the internal capsule and reach the junction between medulla and cervical spinal cord
Some cross at the pyramids, some don’t - forms lateral and ventral tracts
The fibres end up in the dorsolateral area of the ventral horn
What happens if there is a lesion in the corticospinal tract or rubrospinal tract
Loss of fractioned movement - cant move shoulder, elbow and wrist independently
Slower, less accurate movement
Posture maintained
What happens if there is a lesion in the corticospinal tract but rubrospinal tract is spared
Will have motor deficits such as slower, less accurate and loss of fractioned movement
But sparing the rubrospinal means there is a chance of recovery
What areas does the lateral corticospinal tract control
Motor control of the limbs and digits
What areas does the anterior/ventral corticospinal tract control
Motor control of the trunk and maintains posture
When is facial sparing seen
In lesions/disease of the upper motor neurons
Which of the spinal tracts is dominant
Corticospinal
Rubrospinal is second most dominant
What happens if there is a lesion in the corticospinal tract in terms of dominance
The rubrospinal will take over and the upper limb will flex
Which spinal tracts are ascending tracts
DCML
Spinothalamic
What is the function of the frontal lobe
Executive function - decision making etc
Personality
The T10 sensory dermatone is at which anatomical landmark
Umbilicus
What is the vermis
A midline structure in the cerebellum which s concerned with the maintenance of axial (midline) posture and balance
