Week 6: Motor and Sensory Function Flashcards
Somatic nervous system
innervates skeletal muscle (voluntary muscle);
provides sensory and motor innervation to all parts of the body
- touch, pain, temperature, position
autonomic nervous system
innervate smooth muscle (involuntary muscle) in the intestines, sweat and salivary glands, myocardium, and some endocrine glands. The autonomic nervous system functions as a unit to maintain constancy in the internal environment
nerve root
Nerve root: portion of the peripheral nerve that connects the nerve to the spinal cord
dorsal
Dorsal: where incoming sensory nerves comes to synapse
ventral
Ventral: where motor nerves exit the spinal cord
Why are peripheral nerves called inert tissues?
not contractile
What are some morphological factors that contribute to muscular strength?
- cross sectional area
- fibre arrangement, pennation increases strength
- tendon stiffness: stiffer tendon, increased force production
What are some ways muscular strength can be measured?
- max single rep effort
- manual muscle testing
- hand held dynamometer
- modified sphygmomanometer (grip strength)
What could cause drop foot?
lesion at L4. disc herniation
Myotomes
- define
- what would happen if a lesion to a single nerve root occured?
- objective of myotome testing?
are defined as groups of muscles that are predominantly supplied by a single nerve root
A lesion of a single nerve root is usually associated with paresis (incomplete paralysis) of the myotome (muscles) supplied by that nerve root
objective: identify which nerve root is responsible for pathology; potential lesion
How to test myotome? basically methodology
The examiner should place the test joint or joints in a neutral or resting position and then apply a resisted isometric force
The contraction should be held for at least 5 seconds and repeated 3 times to show if there is fatiguable weakness.
Positive findings indicate neurological impairment as opposed to muscle weakness
What are the actions of the lower limb myotomes?
Kick!
L1-L2: hip flexion
L3: knee extension
L4: ankle dorsiflexion
L5: toe extension
S1: plantarflexion and eversion
S2: hip extension and knee flexion
S3: knee flexion
What are the actions of the upper limb myotomes
yes, listen, huh, salute, at rest, woof, piano
C1-C2: neck flexion
C3: neck side flexion
C4: shoulder elevation
C5: shoulder abduction
C6: elbow flexion and wrist extension
C7: elbow extension, and wrist flexion
C8: thumb extension and ulnar deviation
T1: hand intrinsics (abduction and adduction)
negative features:
lessening or absence of normal behaviours
positive features
excess or change in normal function
Define: upper motor neuron syndrome
- negative features
- positive features
Includes lesions involving the corticospinal pathways; Levels of involvement include: brainstem, spinal cord, Cortex, internal capsule
- weakness, slowness of movement, impaired condition
+ spasticity, hyperactive muscles, rigidity, intensional tremors, dystonia
spasticity
hyperexcitability of the muscle - constant problem (example: CP)
dystonia
neurological movement disorder characterized by involuntary (unintended) muscle contractions that cause slow repetitive movements or abnormal postures that can sometimes be painful
Define: lower motor neuron syndrome
- symptoms
+ symptoms
Damage to lower motor neuron cell bodies or their peripheral axons
Negative features: Paresis (weakness), Hyporeflexia (decreased or absent reflex response), Rapid atrophy, Fatigue
Positive features: Fasciculations (involuntary muscle contractions), Spasms
paraesthesia
Paresthesia can be defined as an abnormal sensation of pins and needles, numbness, or prickling
Sensibility
describes the neural events occurring at the periphery, nerve fibers, and nerve receptors.
What is a pain gait
provides additional sensory input to override pain (pressure, touch, vibration, etc.) - TENS machine
Anterior spinothalamic tract
Function
decussates?
- light touch and pressure
yes
Dorsal Column – Medial Lemniscal tract
function
decussates?
proprioception
vibration
fine touch
yes
What happens if theres a lesion somewhere in the dorsal column medial lemniscal pathway?
- Loss of discrimination: the patient cannot differentiate a single touch from a two-point touch.
- Loss of vibration sense: the patient cannot perceive the vibration of a tuning fork placed on a bone.
- Loss of sense of position and movement: the patient cannot state the position of his body in space, without visual input.
lateral spinothalamic tract
function
decussates?
Pain
Temperature
yes decussates
ALP, DPFV, LPT
A little parrot, dove past ferrets, veerring left past tarots
Anterior spinothalamic tract
Light Touch
Pressure
Dorsal-column medial lemniscus
Proprioception
Fine touch
Vibration
Lateral spinothalamic tract
Pain
Touch
Dermatome
A dermatome is defined as the area of skin supplied by a single nerve root. The area innervated by a nerve root is larger than that innervated by a peripheral nerve
How can you test dermatomes?
- pain: pin prick vs blunt- ask if they can feel it
- light touch: tap the person’s skin with a piece of cotton or your finger tips, avoid dragging cotton or finger across skin
- proprioception: hold the distal phalanx between two fingers, move the finger up and down so the person understands which direction is up an down, ask them to close eyes and move the joint up or down and ask them to say outloud which direction their joint moved. begin with large movements and then gradually reduce size of movements. begin with distal digits then move proximally
reflex
involuntary, predictable, and specific response to a stimulus dependent on an intact reflex arc
Types of Reflexes
Deep tendon reflexes
Proprioceptive reflexes
Cutaneous reflexes
Describe what makes up a reflex arc
afferent sensory neuron
efferent motor neuron
interneurons
muscle
Hyporeflexia
An absent or diminished response to tapping. It usually indicates a disease that involves one or more of the components of the two-neuron reflex arc itself.
Hyperreflexia
Hyperactive or repeating (clonic) reflexes
These usually indicate an interruption of corticospinal and other descending pathways that influence the reflex arc due to a suprasegmental lesion, that is, a lesion above the level of the spinal reflex pathways.
deep tendon reflex
- define
deep tendon reflex (DTR) results from stimulation of the stretch sensitive IA afferents of the neuromuscular spindle producing muscle contraction via a monosynaptic pathway
if DTRs are increased or decreased, what does this indicate?
DTRs are increased in upper motor neuron syndrome (e.g., stroke) and decreased in lower motor neuron syndrome (e.g., peripheral neuropathy, nerve root compression), cerebellar syndrome, and muscle disease.
deep tendon reflex testing objective and methodology
DTR objective: determine if there is an upper motor neuron syndrome or lower motor neuron syndrome causing patient’s sympatmology
DTRs are tested by tapping sharply over the muscle tendon with a standard reflex hammer or with the tips of the therapist’s fingers. They are then rated from 0-4
- 0 = absent (areflexia)
1 = diminished (hyporeflexia)
2 = average (normal)
3 = exagerrated
4 = clonus, very brisk (hyperreflexia)
Discuss the site of stimulus and expected resonse when checking the DTR of:
- biceps
- triceps
- biceps: biceps tendon; expect bicep contraction; C5-C6
- triceps: distal triceps tendon above the olecranon process; elbow extension/ muscle contraction, C7-C8
Describe Hoffman’s reflex test
Objective
Methodology
Findings
objective: verify the presence or absence of an issue arising from the corticospinal tract
loosely holding the middle finger and flicking the fingernail downward, allowing the middle finger to flick upward reflexively
A positive response is seen when there is flexion and adduction of the thumb on the same hand. Eg. in hypertonia, the tips of other fingers flex and the thumb flexes and adducts.
Discuss the site of stimulus and expected resonse when checking the DTR of:
- patellar
- achilles
- hamstring
patellar: patellar tendon, leg extension, L3-L4
achilles: achilles tendon, plantarflexion of foot, S1-S2
clonus test
- objective
- methodolgy
- findings
- objective: determine if upper motor neuron syndrome or lower motor neuron syndrome
- methodology: extend the wrist or dorsiflex subject’s ankle, then quickly apply overpressure.
- the subject’s movements should oscillate 1-2 beats but more than 3 beats is a positive sign and indicative of UPNS
babinski
- objective
- methodolgy
- positive findings
- objective: determine if upper motor neuron syndrome or lower motor neuron syndrome
methodology: stroke lateral aspect of sole of foot
positive sign: big toe extends and small toes fan out
Corticospinal tract disruption (pyramidal). upper motor neuron syndrome
if a person can’t smell coffee, what nerve is affected?
cranial nerve 1 - olfactory
if a person can’t see fingers in their peripheral vision, what nerve is affected?
cranial nerve 2 - optic
if a person’s pupils don’t constrict in response to shining light, and/or can’t smoothly pursuit an object up or down, what nerve is affected?
CN3- occulomotor
if a person can’t follow an object diagonally in their field of vision smoothly - what nerve is affected?
CNIV (4) - trochlear
if a person can’t feel sensation on their face, or if their jaw muscles can’t open and close well what nerve is affected?
CNV - trigeminal
if a person can’t follow an object laterally or they say they have double vision, what nerve is affected?
CNVI - abducens
if a person can’t raise their eyebrows, close eyes, smile, or puff cheeks normally, what nerve is affected?
CNVII - FACIAL
if a person has different hearing acuity between ears, what nerve is affected?
CNVIII - auditory/vestibulocochlear
if a person has a lack of gag reflex what nerve is affected?
CNIX - glossopharyngeal
if a person has asymmetrical elevation of the palate when asked to say ahh, what nerve is affected?
CNX - vagus
if when a person protrudes their tongue and it deviates from the midline, what nerve is affected?
CNXII - hypoglossal
