Neuro Exam II: Motor, Sensory Reflexes Flashcards
The Motor System of the brain
- organization
- Motor Cortoex (the precentral gyrus in the frontal lobe)
- motr tracts: carry the information (corticobublar(CN) or corticospinal)
- spinal roots: speciifcally the anterior horn in which they leave
- motor neurons
- to the target organ
The Motor Cortex
location
somatotopic organzation
arising spinal tracts
Motor Cortex
- the pre-central gyrus in the frontal lobe (BA: 4)
- signals come from the prefrontal cortex to the motor cortex
Somatotopic organization
- the lower extremities are towards the middle: medial
- the upper extremities & face: lateral
Collectively, the signals travel on pyramidal tracts (because they pass & deccusate at the pyramids in the medulla)
- the corticobulbar tract
- the corticospinal tract
these are efferent nerve fibers of UMN that travel from teh cortex and terminate either in the brainstem (bublar) or in the SC
Corticospinal Tract Pathway
Corticobulbar pathway
corticospinal
from the motor cortex
to the medulla
cross at the pyramids to the contralateral side
travel down to their SC level
synpase at the SC level in the anteriro (ventral) horn
go to target organ
____________________________________
corticobulbar
from the pirmary motor cortex
to the midbrain & lower medulla
medulla oblongata of the BS specifically
travel through their nuclei (innervate ipslateral and contralateral CN)
UMN and LMN
UMN: upper motor neruon
- those which travel from the motor cortex/BS
- travel to and synpase with a LMN at the BS (if bulbar) or SC (peripheral nerves)
UMN lesion: hyperreflexia, hypertonia
LMN: lower motor neurons
- those which are from the spinal cord (anterior/ventral) horn that travel to teh anterior roots & to the peripheral nerves
- they’re terminated at the NMJ and their target muscle
LMN lesion: weakness, parlysis of the ipsilateral side, hypotonia and decrease or absenct DTR
Sensory System organiaion & pathway
spinothalamic path and dorsal path
Afferent organ
peripheral nerve travels to the spinal nerve
to the spinal pathways (spinothalamic or posterior/dorsal column)
to the sensory cortex in the parietal lobe (BA:1,2,3)
Spinothalmic
- the pain, temperature and crude touch pathway
- travels from the peripherl nerve
- into the SC: synpases and crosses over at the SC level
- travels up to the contralateral sensory cortex
Posterior Column/Dorsal Column
- teh vibration, proprioception and light touch
- travels from teh peripheral nerve
- to the SC: and up
- crossed over and synpases at the level of the medulla
- (travels in the form of the nucleus gracilis or nucleu cuneatus)
Organization of the Spinal cord
- where is white and grey matter
- afferent and efferent fibers are where
Spinal Cord
- the grey matter in the interior: the butterfly shape
- the white matter is the edges: the axons of the nerves
Afferent/Sensory Nerves
- Dorsal root: carry afferent from the peripheral nerves
- DRG: from the doral root & contains the bodies of the primary sensory nerurons which traveled through particular nerves & participate in sensory modualtion and pain transmission (DRG: cell bodies of the peripheral nerve)
- dorsal column: carry the interneuronal signal from the dorsal root & peripheral nerves & DRG into the SC & the axons collect into this long pathway up to the brain
Efferent/Motor Nerves
- Anterior(ventral) horn: the cell bodies for these LMNs which then go out to the target
- anterior root: the efferent nerve motor fibers pass ventrall here and leave the SC this way
Somatotopic organization of the SC tracts
Dorsal Column tract
- sits posteriorly (dorsal) & has the LE more medial and the UE more lateral
Lateral Spinothalamic Tract (pain and temp)
- sits laterally & has the UE more medial then the LE
Ventral Spinothalmic Tract (light touch)
-sits ventral/anterior (small)
Lateral Corticospinal Tract
- sits laterally and has UE more medial than the LE
Ventral Corticospinal tract
- sits ventral and has some motor control (small)
Landmark Dermatomes to know
C3
T4
T10
L1
L3
L4
L5
S1
C3: Front of neck
T4: nipple line
T10: umbilicus
L1: inguinal/groin
L3: does not go belwo the knee
L4: knee to medial malleolus
L5: anteriorn shin/ankle & foot (dorsum)
S1: lateral shin/calf, ankle and foot, lateral malleolous and sole
Upper Cervical Spine
Nerves
C1-C4 = cervical plexus
C1n = geniohyoid & thyrohyoid
C1-2 = rectuc capitus anterior and lateralius
C1-3: longus capitus
C2-3: SCM
C1-3: ansa cervicalis (to the omohyoid, sternohyoid and sternothyroid)
C3-4: levator scapula, trapezius & scalence
C3-5: Phrenic n = to the diaphgram & anterior scalenes
Axillary Nerve
nerve roots
sensory innervation to what
motor to what
Nerve Roots: C5-6
To: the teres minor and the deltoid
motor test: shoulder abduction
sensory: upper lateral cutaneous nerve (the skin over the deltoid)
Radial Nerve
nerve roots
Motor innervation
sensory innervation
Radial Nerve: C5-T1
innervates: triceps brachii & extensor forearm muscles (for wrist)
Motor testing: wrist extension & tricep extension
Sensory
- most of the posterior forearm
- lateral dorsum of the hand
- dorsal aspect of fingers 3-5
Musculocutaneous Nerve
- roots
- motor innervation
- sensory innervation
Musculocutaneous nerve
Roots: C5-7
Motor innervation
- the anterior arm muscles (biceps brachii, coracobrachialis & brachilais)
- test: via elbow flexion
Sensory Innervation
- lateral cutaneous nerve of teh forearm & lateral aspect of the forearm
Median Nerve
Roots
Motor Innervation
Sensory Innervation
Median Nerve: C6-T1
Motor Innervation
- flexor & pronator mucles in the anterior forearm (pronator quadraus, flexor digitorum profundus, flexor pollicus longus)
- thenar muclse and lumbricals
- test = wrist flexion, thumb adduction, pinching & interosseous testing (abdut fingers against pressure)
Sensory Innervation
- palmar cutaneous branch (lateral palm)
- digital cutaneous branch ) digits 1-2 & 1/3 of 3) from palmar surface
Ulnar Nerve
roots
motor innervation
sensory innervation
Ulnar Nerve: Roots C8-T1
Motor Innervation
- anterior forecarm, flexor muslces and intrinsic hand muscles (except those from the median nerve: lumbricals and thenar)
- test = wrist flexion & hand interosseous testing
Sensory Innervation
- medial 1/2 of the palmer aspect of the 3rd and 4th and 5th digit
how to accurately test dermatomes for sensory loss
common complaints
- radicaulr pain (burning, tingling, numbness and aching)
test
- pin prick and light touch sensations in the dermatomal pattern
Femoral Nerve
Roots
Motor Innervation
Sensory Innervation
Femoral Nerve: L2-L4
Motor Innervation
- thigh muscles which flex the hip (iliacus, sartorius, pecineus)
- thigh muscles which extend the knee (quadraceips femoris)
- test = knee extension
Sensory Innervation
- cutaneous branches to anterior medial thigh
- cutaneour bracnhes to the medial side of teh leg and foot
Obturator Nerve
roots
Muscle Innervation
Sensory innervation
Obturator : L2-L4
- medial thigh compartment muscles (adductor longus, brevis, gracilis)
- test = thihg adduction
Sensory innervation
- cutaneous branches to the medial thigh
Sciatic nerve
roots
motor
sensory
Sciatic nerve: L4-S1
Motor Innervation
- muscles of the posterior thigh (biceps femoris, semiten, semimem) & hamstrings portion of adduct magnus
- indirectly innervates all mucles of the lower leg/foot due to its branches
- test = knee flexion, ankle plantaflexion/dorsiflexion, inversion & EHL flexion
Sensory Innervation
- no DIRECt sensation innervation: but termial branhes go to lower legs (peroneal nerve) and dorsa;/plantar aspects of the foot
Tibial Nerve
roots
muscle innervation
sensory innervations
Tibial Nerve: L4-S1 from siatic
Motor Innervation
- posterio compartment of the leg and intrinsic foot muscles (plantaflexion msulces, gastrucnemus)
- test = ankle plantaflexion
Sensory Innervation
- to the sural nerve: skin of the poserior lateral leg and lateral foot
- some branches to the heel and medial foot/sole
Fibular Nerve
Roots
Muscle Innervation
Sensory Innervation
Fibular Nerve: L4-S2
Motor Innervation
- short head of the femoris
- branches into the superfiscal fibualr and deep fibular
- superfisical: lateral compartment of the leg; foot eversion
- deep: anterior compartment of the leg (front): dorsiflexion and extend digits
- test = ankle dorsiflecion and eversion, EHL extension
Sensory
- skin on the lateral lega and dorsum of the foot
Note on ROS: Neruo Symptoms
definding and explaining weakness
Weakness - clarify what the pt. defines as weakenss
- fatigue? atrophy? drowsiness?
- or ACTUAL loss of strength
always specify the following
- location of the weakness
- bilater or unilateral
- proximal/distal?
Weakness: noticable decrease in the power of a muscle or multiple muslces
- distrubution: generalize, symmertric, asymmetric, proximal, distal etc.
- identify timing: in the morning or after use
- excerbating factors? activity/climbing staris, etc.
ask if there is bladder/bowel incontinece
ask if any changes to gait
Motor System
Inspection
Muscle Bulk
Muscle Tone
Muscle Strength
Inspection
- body positioning: posture at rest and activity
- abnormal movments: tics, tremos, fasciulations, etc. (rate,quality, rhythm,etc.) & posture/position when movements occur
Muscle Bulk
- asses atrophy or muslce wasting
- looking at hands, shoulders and thighs
- take note of atrophic areas
- always compare bilaterally & meausre the difference
Muscle Tone
- when muslces at relaxation maintain a residual tension = this is tone
- moving each large joint through PROM & noting resistance
- abnormalities: flaccidity, spacticity, rigidity
Muscle Strength
- grading from 0 (absent) to 5 (normal)
- 1 = barely detecable movements
- 2 = active movement but not against gravity
- 3 = active movement against gravity
- 4= movemnet against gravity and some resistance
Muscle Strength
- muslce & cooresponding nerve & spinal nerve
- deltolid
- elbow flextion
- elbow extension
- wrist extension
- wrist flexion
- grip strength
- finger abduction
- thumb opppostion
Deltoid = Axillary Nerve (C5)
Elbow Flexion = (biceps) musculocutaneous n. (C5-C6)
Elbow Extension = (triceps) radial n. (C7)
Wrist Extension = radial nerve (C6)
Wrist Flextion = ulnar and median (C6-C8)
Grip strength = C7,8 & T1
Finger Abduction = raidal and ulnar . (C7-T1)
Thumb Opposition = median nerve (C8,T1)
Muscle Strength
- muslce, nerve and spinal nerve root
- Hip Flexion
- Hip Extension
- Hip Add.
- Hip ABD.
- Knee Extenion
- Knee Flextion
- Dorsiflex
- Plantanflex
Hip Flexion = (illiopsoas) femoral N. (L2-L4)
Hip Extension = (glut. max.) gluteal N. (L4-L5)
Hip Add = (adductors) obturator n. (L2-L4)
Hip Abd = (gluteus medius and min.) superior glut n. (L4-S1)
Knee Flextion = (hamstrings) siatic n. (L4-S2)
Knee Extension = (quadraceps) femoral n. (L2- L4)
Dorsiflex = (tibialis anterior) deep peroneal n. (L4-L5)
Plantarflex = (gastrucne. * soleus) tibial n. (S1-S2)
eversion = superfiscal peroneal n.
inversion = tibial n.
Abnormalities of the Motot System
atophy
involuntary movements
dyskinesia
tics
dystonia
Atrophy = muscle wasting
Involuntary movements
- Dyskinesia: involuntary, repeitive & bizzare facial movements (example is tartive dyskinesia)
- dyskinesia can be a result of antipsychotic use, prolonged levodopa or stimulants (cocain, ampehtamines)
- Tics: involuntary, sudden, rapid movemetns or sounds (Tourettes or drugs)
- muscle tics = one muscle group (blinking, head tilting)
- vocal tics = nose, mouth or throat
Dystonia = muscle contrations which are uncontrollable making a body part twist = abnormal posturing
- can be due to abnormal basal gangliaor cerebellum
- can be from medications (antipsychotics) or infections (lead positon, meningitis, trauma)
Motor Abrnomalities (con.)
Chorea
Athetosis
Hemiballismus
Chorea: nearly continuous rapid dance-like fluiditiy movements of the face, tongue or limbs
- a key sign in Huntington’s disease (start of these signals the decline) as the straitum and caudate are atrophied
Athetosis
- SLOW writithering movements of the extremities due to abnormal muscle contractions
- pt. often unable to keep the limb still when ased to
- cerebral palasy (lack of O2 ot basal ganglia)
Hemiballismus
- the most dramatic of moveents due to a basal ganglia disorder, where there is Irregula, wild fialing of the arm and leg on one side of the body ONLY
- often seen in those after a stroke to the basal ganglia
Tremors & Types
Fasiculation
Resting Tremor
- fine or coarse movements
- worse at rest
- goes away with activity
- parkinsons
Postural Tremor
- affected area held in a specific postion (like outright arms) brings on the tremor
- aneixty, bening essential, etc.
Intention Tremor
- absent at rest
- exacerbated when the pt. is doing activities (cerebellar or MS)
Fasiculation: spontaneous fine movemnets due to involuntary contraction of the fine motor muscle fiebrs
- appears as small, fine muscle twitches
- can be associated with late stage ALS
- can also be benign, anxiety, caffeine, medications (stimualants, sympathomimics, anticholenergics)
Tone Abnormalities
spacticity
rigidity
flacciity
Spacticity: sudden catch follwed by resistance
- spacticity seen in UMN lesions
Rigidity: resistance during ROM
- seen in Parkinsonism
Flaccidity: decreased tone
- seen in LMN lesiosns (and spinal shock!)
Sensory System
- postivei v negative symptoms
- specifics about the complaint of numbness
Postive: heightened excitability at a peripheral or central pathway
- pain
- paraesthesias (tingling)
- dysethesia (abnormal sesanation)
Negative: lossed or dimisehd sensory function or feeling
- numbness
- anesthesia
alwasy differentiate between the disturbution of the sensation & how it changes during activity
Numbeness
- ask pt. to explain exactly what is “numb”
- parasthesias (tingling, pins/needles)
- or dysthesia (painful burning)
- or is gone (anesthesias)
- bilateral? proximal? distal?
- assess if its a single nerve pattern
- or is it stocking-glove mutliple?
The Sensory Exam
what are you testing
- Light Touch: compare bilateral and distal to proximally
- Pain: sharp & dull test: compated bilaterally and distal to proximal
- Temperature: only done if abnormal pain/light touch sensation: hot and cold
- Vibration: starting on the DIP of fingers and then toes; start distal and move proximla if not left (feel it and when you feel it stop) (compare bilateral)
- Proprioception: identify if it is “up” or “down”: if cant at teh DIP move proximal and comapre bialterally
Sensory Exam : Cortical Senses
Streogensis
graphesthesia
two point discrim.
posint localization
extinction
Stereogenesis: identify object in hand with eyes closed
Graphesthesia: feel the number drawn in the hand
Two Point: touch two places simultaneouly and deicde if they can identify where, and two separte touches
Point Localization: eyes closed, poke in a spot and have they show you wher you poked
Extinction: touch two sides of the body & have them point (should be able to feel that its two different points)
Abnormalities in the Sensory System
Mononeuropathy
Polyneuropathy
testing for diabetic neruopathy
deficts in the sensory system: identify the pattern, dermatome? cortical? or peripheral nerve/cutaneous
Mononeuropathy: a single nerve distrubution is deficit
- can have associated muslce deficts
- ex. carpel tunnel, axillary nerve palsay, inflmmation, etc.
Polyneuropathy: mutleipl nerves lost modalitiy
- sx. numbness, tingling, burning, pain, etc.
- think stocking/glove example for diabetic neruopathy (multiple nerves in the same area)
Diabetic Neuropathy
- stocking/slove distrubtion
- monofilamanet testing
- vibration sensation test
Posterior Cord Syndrome
loss of the posterior tract only sensory loss
- lost position sense & vibration below lesion
- in tact pain and temperature
- rare; not common
due to
- trauma
- B12 def.
- demyleinating conditions (syphilis, MS)
- infarct of posterior spinal artery
Cerebral Cortex Abnormalites: Sensory Findings
Thalmic Lesions?
Brainstem Lesions?
Cerebral Cortex
- all the modalities on the contralater side will be effected
- loss fo sensation, two point discrimination
- extinction (sensory inattention) to the other side
- causes: stroke, hemorrage, tumor
Thalmaic Lesions
- contralateral loss of all sensory modalities
- because at this point the fibers should be crossed or crossing at the medulla so if they cant, you lose everything
- Causes: infarct, trauma, tumor, hemorrahge (HTN bleed)
Brainstem Lesions
- variable motor/sensory loss depends on the location
- commonly: ipsilateral loss of facial sesnetion and contralatera body sensation
- if it is the basal ganglia, cerebellum or frontal lobe = no sensory loss, only motor
Spinal Nerve Root Compression
- radicular symptoms within that spinal nerve distrubution
- sensory loss (all modes)
- +/- motor loss
- radicular pain (shooting, sharp)
- abnormal reflexes: hyporeflexia,hyperreflexia
causes
- herniated disc
- degenertive spinal disease
- abcessess
- spinal cord tumor
- cyst
Cauda Equina Syndrome
- symotoms due to a spinal nerve root compression at the lumbosacral region
Causes
- a LARGE herniation of a disc in the lumbar region
- trauma to lumbar
- tumor, abcess or hematma in lumbar
Symptoms
- back pain
- radicular pain bilaterally to the legs: siatcia on both
- urinary retention that leads to loss of bladder/bowel function (overflow incont.)
- lower extremitiy weakness (absent reflexes)
- saddle anesthesia (groin)
Central Cord Syndrome
Anterior Cord Syndrome
Central Cord
- loss of upper pain/temperature sensation bilaterally at the level of the lesion (usually shoulders and arms)
- posterior column preserved
- decreased motor strength in the upper extremities
- MC incomplete spinal cord injury
- “cap or shawl” sign
- usually due to a fall or trauma
Anterior Cord Syndrome
- sensory: loss of pain and temperature below the lesion
- preserve vibration/proprioception below
- complete parlysis below the lesion & bladder dysfunction
- due to throbosis of teh snterior spinal artery or compression
Brown-Sequard Lesion
Complete Severed SC
Brown-Sequard: hemisection
- loss of pain and temperature on the contralateral side below the lesion
- loss of vibration & proprioception on the ipsilateral side below
- loss of motor function below ipslaterally
- caused: transverse myleitis (infection)
Complete Severed
- lost all function motor and sensory belwo
Median Nerve Neuropathy
Ulnar Nerve Neuropathy
Radial Nerve Neuropathy
Median Nerve
- “Carpel Tunnel” syndrome most common
- compression of median nerve in the canal
- weakness/atrophy of thenar space
- pain/parastehisas in forearm, wrsit and digits 1-3
Ulnar Nerve
- cubital tunnel syndrome elbow: MC
- pain, numbness/burning of 1/2 digit 3, then 4 & 5 = worse with elbow flexion
- tender at the elbow cubital tunnel
Radial Neuropathy
- saturday night palsay: tramatic injury to the upper arm @ shaft of humerus
- prolonged compression: wrist drop because weakness to the extenors
- compression = parasthesia’s
Sciatia
Femoral Neuropathy
Peroneal Neuropathy
Tibial Neuropathy
Sciatia (L4-S3): pain in the gluteal, hip and posterior thigh region
- can be due to lumbar radiculopathy
- periphearl causes (mucles compression on the nerve)
Femoral Neuopathy
- compression and ischemic injury from surgery att he hip or pelvis
Peroneal Neruopathy
- trauma to the fibular head (crossed legs)
Tibial Neruopathy
- tarsal tunnel syndrome from shoes or boots too tight, or a twisted angkle/fracture
DTR’s
- what are they
- grades
What is a DTR
- invluntary sterotypical reflex due to two neurons (monosynamtic arch)
- connection from afferernt to effernt neruon in the SC
Grading
0 = no response
1 = slightly dimished
2 = normal
3 = slightly brisk
4 = hyperactive with clonus
Biceps (C5,6)
Tricepts (C6,C7)
Brachioradialis (C5,C6)
Patellar (L2,L3,L4)
Achilles (S1)
Abdominal : (T8,9,10) & (T10,11,12) umbulicus toward stimuli
Clonus: rhymic occilation of ankle back and forth when provoked (CNS injury)
Plantar Reflex: shoule curl in (flexion of toes)
Hoffmans: flick middle finger downard: if it hyperrelfex in the finger (UMN lesion) -could benormal bilateral; concenring if unilateral ;think cord compression
Cutaneous Anal reflex: stroke skin outward in four quadrants from anus
- should contract
- lost reflex: thinkg S2, S3, S4 reflex arc issue (cauda equina)
