UMNL Vs LMNL Flashcards
Spinocerebllar tract route and function
Posterior
Unconscious propricepion
Function: fine coordination of posture, movement of trunk and lower Limb
Dorsal root ganglion, uncrossed,
Lateral funiculus
Medulla oblongata
Inferior cerebella peduncle
Cerebellum
Anterior
Unconscious propriception
Gross coordination of posture, movements of trunk and lower limbs
Dorsal root ganglion
CROSSED
Contra lateral lateral funiculi’s
Medulla
Superior cerebella’s peduncle
Cerebellum
Cuneocerebellar function
Unconscious propriception of upper limbs and upper trunk
Dorsal root ganglion
Cuneate nucleus in Medllla
UNCROSSED
Inferior cerebllar peduncle
Cerebellum
Describe pyramidal
Pyramids of medulla oblongata tract travels
Origin cerebral cortex
Carry’s signals to muscles
Responsible for voluntary muscle control
Describe extrapyramidal
Not pass through pyramids
Origin brainstem
Carries motor fibres to spinal cord
Involuntary control
Corticospinal tract
Voluntary, discrete, skilled movements
Lateral: distal limb muscular earl fine movements
Anterior: axial musculature, gross movements
Origin is primary motor cortex, pyramidal cells of cortex
Midbrain
Poms
Medulla pyramid
Crosses
Descends spinal cord
Anterior: cervical and upper thoracic. Synapsids with motor neurons of the level of nerve supply (25%)
Lateral: crosses to other side of spinal cord (75%)
Synapses with lower motor neuron in ventral horn
Supply peripheral msucles
Corticospinal
Voluntary, discrete, skilled movements
Lateral: distal limb muscular earl fine movements
Anterior: axial musculature, gross movements
Origin is primary motor cortex, pyramidal cells of cortex
Midbrain
Poms
Medulla pyramid
Crosses
Descends spinal cord
Anterior: cervical and upper thoracic. Synapsids with motor neurons of the level of nerve supply (25%)
Lateral: crosses to other side of spinal cord (75%)
Synapses with lower motor neuron in ventral horn
Supply peripheral muscles
Rubrospinal tract
Facilitates flexor
Inhibits extensor muscles
Axons from cortex
Red nucleus of midbrain
Crosses in superior coliculus or midbrain
Decsnefds controlateral lay
ELMN full length of ord
Reticulospinal tract
Brain stem
Uncrossed
LMN terminated
Locomotion and postural control
Tectospinal
Reflex postural movements in response to visual stimulus
Arise from superior coliculus of midbrain
CROSSED to superior midbrain
End in ant grey column LMN
Vestibulospinal
Facilitates extensor to maintain posture, balance, inhibits flexor
Origininate vestibular nuclei in medulla
Medial and Lateral
Uncrossed
Terminate lamina
Olivospinal tract
Reflex movements from propriception
Inferior oligarchs nucleus in medulla
Crosses
Descends lateral white column
Terminates anterior horn
Where is UMN lesion
Anything above anterior horn
Descending tracts
Within CNS
Increases spasticity in tone
Muscle weakness in all muscle groups
Impaired or abscent voluntary movement
Increased hyperflexia in deep tendon reflexes
Plantar response (toe flex) is ext
Fascicultation (twitch) is abscent
Disuse atrophy
What constitutes LMN lesion
Motor neurons distal to ant horn
Alpha and gamma motor fibres
Peripheral nervous system inc nerve root
Described muscle tone
Myotomes have muscle weakness
Weak or absent voluntary movements
Decreased hypo reflex in deep tendon
Normal/abscent plantar response
Neurogenic / severe atrophy
Maybe present fascination(twitch)
Structure and function of LMN
Transmit impulses via spinal peripheral nerves or cranial nerves to skeletal muscles
Three distinct types of motor neurons are categorised based on the target branchial, viscera, somatic.
Describe branchial motor neurons
Located in brain stem and are responsible for forming LMN of cranial nerves 5,7,9,10 or
They innervated the pharangealk/ branchial arch which include cranial nerves or
Lesions in any region from cranial nerve nuclei in the brainstem to these muscles would result in LMN deficits
Describe visceral motor neurons
Components of autonomic nervous system and regulate smooth muscles and glands.
Broken down into sympathetic and parasympathetic nervous system
MN from sympoathetuic are present from T1 to L2. Regulate ‘fight or flight’ dictates body metabolism, awareness energy storage
Parasympathetic nervous system regulates some cranial nerves 7,9,3
S2- S4
‘Rest and digest’ GI mobility and sex drive.
Describe somatic motor neurons
Traditional motor neurons located in ventral horn of spinal cord and directly innervated the skeletal muscle,
They receive stimuli from UMN from the primary motor cortex and relay the info from spinal cord to their target.
Alpha MN innervated extrafusal fibres and are responsible for muscle contraction. Largest and fastest, thickest myelin sheath. Voluntary movement
Beta MN innervated intrafusal fibvrers which act like propriceptors and detect change in muscle length. Sensory fibres involved with touch, pressure and propriception
Gamma MF innervated intrafusual muscle fibres too. Motor fibres which regulate sensitivity of muscle spindles.
Abnormalities present in spinal muscular atrophy and irreversible paralysis
What is bell palsy
Mc ethology of peripheral facial nerve palsy
Develops after herpes virus reactivation, Lyme disease, tumours or parotid gland, diabetes mellitus, stress
Recovery is 3-6months mc
Corticobulbar tract from motor cortex of facial nerve nucleus uis damaged .
LMN issue mc , muscle weakness
Lower half of the face received input from the Controlateral side of the brain
Upper receives from both sides which is why it is less likely affected
-facial paralysis involving lower facial expression
Incomplete eye closure, dry eyes, taste sensation loss to anterior tongue, loss of facial expression on affected side, one side face droop, drooling after eat or drink. Increased sensitivity to sound in one ear
Sudden onset
Structure and function of UMN
First order neurons responsive fort carrying electrical impulses that initiate and modulate movement
Various UMN responsible for coordination fo movement
Initiates voluntary movement in pyramidal tract
Describe the triad of meningitis
Fever: high fever is mc early sign indicting infection and inflammation
Headache: severe and persistent. Intense unlike a regular headache
Neck stiffness: hallmark symptoms, personal experiences difficulty bending their neck forward, accompanied by pain. Due to irritation if the meninges surrounding spinal cord and brain
Nausea, vomiting, rash, sensitivity to light also can be signs
Describe meningitis
Inflammation of the meninges which surround the brain and spinal cord. Bacterial, viral or fungal but can result from causes like autoimmune diseases, meds or cancer
Dura matter (outer) arachnoid matter and PIA (inner)
Issues arise from the proximity to the brain and spinal cord, affecting cognitive function, motor control and sever systemic illness
1.bacterial is most serious and life threatening. Can Progress rapidly causing severe complications like brain damage, hearing loss or death
Respiratory droplets
Viral: more common, less severe. Can resolve on own. Herpes, mumps or transmitting can cause
Fungal:rare. Immunocompromised individuals like HIV, AIDS, organ transplant, chemotherapy
Why is it important to assess dermatome
Link this to Testing for vibration
To help diagnose neurological conditions more accurately, to assess if the issue is from upper or lower motor neurons.
Disturbances at a particular dermatome it can help pinpoint the level of nerve damage or spinal cord injury
We want to test if the issue is a local entrapment or something more severe like MS which is….
-Vibration which is a dorsal column tract. -This is ipsilateral and doesn’t decusate (nerve fibres don’t cross from one side of body to other) tillbrain stem
-This test is sensory, propriceptive test
-a positive test would be issue feeling it, whereas negative would have the same sensation both sides, being able to feel
-Then we would test it on a distal bony prominence as we don’t want to test this on soft tissue.
What is a UMN
Nerve cells in the brain and spinal cord that are part of a motor system, controlling VOLUNTARY MOVEMENT
They send signals to LMN, stimulating them to move
Located in cerebral cortex and brainstem
What is a LMN
Nerve cells that connect spinal cord or brainstem to muscles, they allow muscle contraction
Cell bodies located in the anterior horn
