PNS exam

Question 1

Scope of the nervous system: CNS

Answer 1

Cortex
Basal Ganglion
Brain Stem
Cerebellum
Spinal Cord

Question 2

Scope of the nervous system: PNS

Answer 2

Cranial Nerves
Motor Efferents
Sensory Afferents
Neuromuscular   Junction
Muscle itself

Question 3

Narrowing the scope

Answer 3

Narrow the picture as much as possible using a good history. Look to answer these questions:
Local or diffuse?
Restricted to nervous system or include other systems? (fracture? Subdural hematoma? Tumor growth?)
CNS, PNS or Both?
Goal:
Get to WHERE the lesion is; the origin
Then you can develop a meaningful “WHAT the lesion is” differential. Don’t jump too fast!

Question 4

What the central nervous system does

Answer 4

Mental Status and Cognition
Coordination
Cranial Nerves (technically peripheral nerves)

Question 5

What the PNS does

Answer 5

Peripheral Nervous System
Motor: Strength and Motion
Sensation
Reflexes

Question 6

The neuro exam should contain assessment of…

Answer 6

Mental Status: alertness, appropriate responses, orientation to date and place
Cranial Nerves: acuity, pupillary light reflex, eye motion, hearing, facial strength
Motor: major muscle group strength upper and lower extremity, gait, coordination (finger to nose)
Sensory: test toes/feet – one modality of light touch, pain, temp or proprioception
Reflexes: DTR upper/lower, Babinski

Question 7

Peripheral nerves…

Answer 7

Nerves outside the Brain and Spinal Cord

Carry impulses to and from the Cord
Posterior Root = Sensory
Anterior Root = Motor
Peripheral Nerve is merged roots = Both

Question 8

Sensory Pathway

Answer 8

Sensory fibers travel through peripheral nerves to the spinal cord.

Peripheral nerves enter the cord through the posterior horn.

Fibers conducting pain, temperature and crude touch cross over and ascend as the spinothalamic tract to the thalamus.

Fibers conducting position, vibration and fine touch ascend on ipsilateral side as the posterior column to the medulla, then decussate and go to the thalamus.

Both types of sensory tracts exit the thalamus to the sensory cortex for interpretation.

Question 9

2 distributions your exam must include

Answer 9

dermatome and cutaneous peripheral

Question 10

Where can sensory and motor abnormalities be traced to?

Answer 10

Sensory and motor abnormalities can be due to disease/lesion at any level of the central or peripheral nervous systems:

Cerebral hemisphere (sensory cortex or 	subcortical connecting fibers)
Thalamus
Brainstem
Spinal cord 
Peripheral nerves or roots of nerves

Lesions in thalamus or cord may manifest as ipsilateral or contralateral depending on the fibers involved

Question 11

Motor Pathway

Answer 11

Signal begins in the cortex as upper motor neurons.

These travel to the lower medulla to form the pyramids.

Decussation occurs and the tract continues downward as the corticospinal (pyramidal) tract.

Synapses occur along the way between the corticospinal tract and the lower motor neurons found in the anterior horn of the spinal cord at each vertebral level.

Lower motor neuron axons run out the anterior root, short spinal nerve, combine with efferent sensory fibers as peripheral nerves and end as a neuromuscular junction.

Question 12

corticobulbar tract

Answer 12

Corticobulbar tract is the motor connection that ends in the medulla, exits for function there. (head, face)

Question 13

2 divisions of the motor pathway

Answer 13

Upper Motor Neurons: Originate in the cortex to become the motor fibers above the anterior horn of the spinal cord or motor nuclei of the cranial nerves

Lower Motor Neurons: Emanate from the anterior horn of the spinal cord and take the motor signal peripherally to the muscle.
Peripheral motor sensory system

Question 14

History and presentation of peripheral nerve disorders

Answer 14

Most Common Complaints
Pain
Weakness
Paresthesia (numbness/tingling)

Be specific, define the detail 
Associated Features: swelling, rash, spasm,	deformities, mental status
Trauma/Surgery/Medications/Supplements
Personal/Family History
		autoimmune, dystrophies, diabetes, DJD

Not what just is at the moment, but what has changed will give good clues.

Question 15

Most Common Causes

of PNS trouble

Answer 15

Ischemia (arterial stenosis)
Bleeding (TIA,CVA)
Mass/tumor (impingement)
Peripheral nervous disorders (MS, Guillian Barre)
Neuromuscular disorders (myasthenia gravis)
Muscular disorders (dystrophies)

Question 16

Dysesthesia

Answer 16

all types of abnormal sensation including pain regardless of a stimulant being present or not

Question 17

Paresthesia

Answer 17

mostly numb, tingling, pins & needles without pain and without apparent stimulus

Question 18

Anesthesia

Answer 18

absence of sensation

Question 19

Hypesthesia or hypoesthesia

Answer 19

reduced sensitivity

Question 20

Hyperesthesia

Answer 20

Increased sensitivity

Question 21

Hyperalgesia

Answer 21

significant pain in response to mildly painful stimulus (sharp)

Question 22

Allodynia

Answer 22

non-painful stimulus perceived as painful on the skin, sometimes severe (soft touch)

Question 23

5 types of sensation

Answer 23

Pain: pin or sharp end of broken Q-Tip
Temperature: Metal hammer handle is cool
Light touch: Q-Tip, Cotton wisp
Proprioception (Position): Large Toe: up? down?
Vibration: Tuning fork on boney prominence

COMPARE SIDE TO SIDE , proximal and distal in a pattern that covers both dermatomes and major peripheral cutaneous regions.
Instructing the patient to close their eyes enhances sensitivity
Map out any area found abnormal, find the boundaries

Question 24

spinothalamic sensaion

Answer 24

pain and temperature

Question 25

posterior column

Answer 25

proprioception, vibration

Question 26

Discriminative Sensation Exam: Test cortical sensory function

Answer 26

Stereognosis: Identify an object by feel-a 2-point discrimination-b Number Identification: Graphesthesia, Identify shapes/numbers-c

Question 27

Motor exam

Answer 27

``` Side by side comparison: Inspection: atrophy Palpation: tone, soft, firm. Spasm? Strength testing: major muscle groups Reflexes: brainstem, superficial, deep, clonus ```

Question 28

Muscle Strength (again)

Answer 28

``` Measurement Scale of 0-5 0= no movement 1= muscle twitch without joint movement 2= movement with gravity eliminated 3= full strength against gravity only 4= partial strength against resistance 5= full strength against resistance ``` COMPARE SIDE TO SIDE Name for joint motions or muscle group “4/5 left bicep” or “4/5 flexion at left elbow”

Question 29

Dysesthesia/paresthesia in a saddle distribution:

Answer 29

think cauda equina issues, check an anal reflex | Babinski may be positive in CNS disorders as a part of upper motor neuron problems: ALS, CVA, Head Injury, MS

Question 30

Deep Tendon Reflexes

Answer 30

Brachioradialis- C5, C6 Point end into proximal muscle belly Flat end on distal tendon Biceps- C5, C6 Point end onto thumb lying over tendon Triceps- C6, C7 Flat or point end on triceps tendon above olecranon Patellar- L2,3,4 Flat end on patellar tendon below patella above tibia Achilles- S1 Flat end on achilles tendon above calcaneus

Question 31

Deep tendon grading scale

Answer 31

``` 0 = Absent 1+ = Diminished 2+ = Normal/Average 3+ = Mildly over-active 4+ = Highly over-active ```

Question 32

DTR exam tips

Answer 32

Make sure patient is relaxed Palpate location of DTR strike prior to striking Use a quick wrist flick of moderate strength NO MORE THAN 3 strikes on any one DTR location Use distraction/reinforcement techniques jaw clinch for bicep/tricep clasped hand pull for knee/ankle Reinforcement: engage bilateral muscle groups ABOVE the level being tested to block any run away motor neuron signals going up to enhance the reflex signal.

Question 33

Upper Motor Neuron Lesion

Answer 33

``` Spasticity is hallmark (not 100%) Loss of dexterity Up Going Babinski (abnormal) Loss of superficial reflexes Weakness without atrophy of muscle Hyperreflexia of deep tendon reflex (DTR) Etiologies: Stroke Multiple Sclerosis Cerebral Palsy Traumatic Brain Injury Amyotrophic Lateral Sclerosis ```

Question 34

Lower Motor Neuron Lesions

Answer 34

``` Lower Motor Neuron Lesions Flaccid paralysis Muscle atrophy/wasting Hyporeflexia Etiologies: Polio Guillain-Barre Amyotrophic Lateral Sclerosis (ALS) Spinal cord injury ```

Question 35

UMN synopsis

Answer 35

``` Paralysis of movement, not muscle Atrophy from disuse, slight Spasticity, hypertonic DTR increased Babinski up going ```

Question 36

LMN synopsis

Answer 36

``` Paralysis from muscle atrophy Wasting pronounced Flaccid, hypotonic DTR decreased or absent Absent Babinski ```

Question 37

Peripheral nervous system disorders

Answer 37

Polio, Amyotrophic Lateral Sclerosis 2. Herniated Disc 3. Carpel Tunnel Syndrome, Bell’s Palsy 4. Diabetes, Alcoholic Neuropathy 5. Myesthenia Gravis 6. Muscular Dystrophy

Question 38

Where do ALS and polio affect?

Answer 38

anterior horn

Question 39

where do carpal tunnel and bells affect?

Answer 39

along the course of the nerve

Question 40

where does myasthenia gravis affect?

Answer 40

Neuromuscular junction

Question 41

Anterior Horn Cell problems

Answer 41

Polio, Amyotrophic Lateral Sclerosis (ALS) Fasciculations and weakness in a segmental pattern Sensation intact (why?) Weak DTR

Question 42

Spinal nerve root problems

Answer 42

Herniated disc Dermatomal Sensory Changes Weakness ⇨ Atrophy Weak DTR

Question 43

Peripheral mononeuropathy

Answer 43

Carpal Tunnel Syndrome, Bells Weakness and sensory loss in that peripheral nerve distribution Weak DTR

Question 44

Peripheral polyneuropathy

Answer 44

Diabetes, Alcoholic Neuropathy Distal weakness and stocking-glove distribution sensory loss Weak DTR

Question 45

. Neuromuscular junction trouble

Answer 45

Myasthenia Gravis Muscular fatigability Sensation intact DTR intact

Question 46

Muscle trouble

Answer 46

Muscular Dystrophy Weakness primarily in proximal muscles Sensation intact DTR intact or possibly decreased

Question 47

Thoracic Outlet Syndrome

Answer 47

Cause: Compression of the brachial plexus Between anterior scalene and medial scalene or cervical rib Between the clavicle and 1st rib Between the ribs and the pectoralis minor m. Results: Weakness and numbness of the hands and arms due to compressed neurovascular supply.

Question 48

Thoracic outlet syndrome tests

Answer 48

Roos and Adson's

Question 49

Upper brachial plexus injury

Answer 49

waiter's tip

Question 50

Lower Brachial Plexus Injury (less common)

Answer 50

``` The arm being pulled superiorly Catching something overhead Birth trauma (pulling out by the arm) Thoracic outlet syndrome C8,T1 motor palsy/weakness ```

Question 51

long thoracic nerve injury

Answer 51

Causes: Compression between clavicle and 1st rib Axillary surgery Results: Damage in C5-7 region Weak Serratus Anterior m. (winging of the scapula)

Question 52

Median nerve injury causes

Answer 52

``` Crush Injury Pronator syndrome Carpal tunnel syndrome Entrapment of median nerve in the carpal tunnel Wrist slashing Palm injury/laceration Recurrent Branch of the Median Nerve ```

Question 53

tests for carpal tunnel

Answer 53

(median nerve) Tinel’s sign Phalen’s test Reverse Phalen’s (Prayer Test) “Do you get symptoms during sleep?”

Question 54

MEdian nerve injury results

Answer 54

Damage in the C6-T1 region proximally or distally Weak forearm pronation, wrist and digit flexion, thumb abduction and opposition; dropping things. Atrophy of the thenar muscles Paresthesias or loss of sensation to lateral palm, thumb, index & middle finger Ape hand deformity

Question 55

test for pronator syndrome

Answer 55

(median nerve) Resisted Pronation Examiner resists the patient’s effort to pronate. Tingling along the forearm and lateral hand indicates a positive test for median nerve impingement by the pronator teres (the most powerful pronator m)

Question 56

Anterior Interosseus Neuropathy

Answer 56

Causes: Pronator teres impingment of Anterior Interosseus N. Trauma; Tennis Elbow strap too tight Results: Weak flexor digitorum profundus & flexor pollicis longus Test: Pinch grip “OK” sign Inability to pinch the fingers together tip to tip Can also check muscle strength 5-10% difference in strength in normal persons between dominant and non-dominant

Question 57

Ulnar Nerve Injury

Answer 57

``` Fracture of the humerus near medial epicondyle Cubital Tunnel Syndrome Trauma or entrapment of the ulnar nerve as it passes behind the medial epicondyle Laceration near the wrist Entrapment at Guyon’s canal ```

Question 58

Guyons canal syndrome:

Answer 58

This syndrome is also known as an ulnar nerve entrapment at the wrist. At the wrist, The ulnar nerve enters Guyon's canal along with the ulnar artery, which runs just lateral to the nerve. This canal runs along the lower edge of the palm, on the little finger side of the hand. In the middle of the canal, the ulnar nerve splits into its two terminal branches (deep and superficial) that go on to the palm, ring and little fingers.

Question 59

Ulnar Nerve Injury Results

Answer 59

Damage in the C6-8 region Paresthesias or loss of sensation of the medial part of the palm and 4th & 5th digits Weak wrist flexion and adduction (weak flexor carpi ulnaris) Weak finger abduction & adduction (weak interossei) Loss of thumb adduction (lost adductor pollicis) Loss of MCP flexion in 4th & 5th digits (lost lumbricals) Claw Hand

Question 60

Claw Hand

Answer 60

Ulnar nerve injury Extended 4th and 5th MCP joints (lost 3rd and 4th lumbricals) Flexed 4th and 5th PIP (functional flexor digit. Superficialis) Weak flexion of 4th and 5th DIP joints (weak flexor digit. profundus)

Question 61

Radial nerve injury

Answer 61

``` Causes Fracture of the humerus near the radial groove “Saturday Night Palsy” compression by sleeping with arm under head Results Damage in the C7-T1 region Sensory loss to the back of the hand Wrist Drop Weak brachioradialis, supinator, wrist & digit extensors ```

Question 62

Tinel's sign

Answer 62

(at the elbow) | "funny bone"

Question 63

Sciatic nerve injury

Answer 63

Causes: Disc compression on the L4 &/or L5 nerve roots Piriformis Syndrome Posterior hip dislocation Misplaced intramuscular injection Gunshot or stab wounds to the medial buttock Surgery Results: SCIATICA- pain in the path of the sciatic nerve STEPPAGE GAIT- weakness or paralysis of hamstring muscles and thigh extensors and all muscles below the knee: Bates 11th p. 759

Question 64

Superior Gluteal Nerve Injury

Answer 64

TRENDELENBURG GAIT- weak hip abductors and external rotators (gluteus medius) Weak gluteus medius on standing side: cannot hold the opposite hip level.

Question 65

lateral femoral cutaneous nerve injury

Answer 65

Causes Compression at the iliac crest (belts, seats, large bellies, prolonged standing) Results Numbness over the lateral thigh

Question 66

Common Fibular/Peroneal Nerve Injury

Answer 66

``` Causes: Impingement by piriformis (sciatic n.) Proximal fibular fracture Stretched from a varus stress (with lateral collateral ligament ) Compressed by casting Surgery ``` Results: Paralysis of dorsiflexors and everters Loss of sensation of anterolateral leg & dorsum of foot FOOT DROP Patient displays HIGH STEPPING GAIT and FOOT SLAP

Question 67

Superficial Fibular/Peroneal Nerve Injury

Answer 67

``` Causes: Proximal fibular fracture Stretched with varus stress Compressed by casting Surgery ``` Results: Paralysis of foot everters; NO foot drop Loss of sensation of the anterolateral leg and dorsum of the foot

Question 68

Deep Fibular/Peroneal Nerve Injury

Answer 68

``` Causes: Anterior Compartment Syndrome Anterior Tarsal Tunnel Syndrome Pes Cavus (high arch)- less space under the retinaculum Tight shoelaces Trauma ``` Results: Weak dorsiflexors FOOT DROP

Question 69

Medial Plantar Nerve Injury:

Answer 69

Runners Causes Entrapment in the longitudinal arch Joggers Foot- valgus hindfoot & pes planus Results Aching pain in arch and burning/paresthesia in the medial plantar surface

Question 70

Diabetic Peripheral Neuropathy

Answer 70

Estimated 42% of DM patients will develop neuropathy 10 years after diagnosis. Multiple etiologies suspected to damage peripheral nerves faster than they can heal Paresthesias and pain of feet > hands Intense burning especially at night in the distal extremities (Bilateral Stocking and Glove distribution) Loss of vibratory, pain, temperature, light touch sensations. Loss of proprioception can cause ataxia and steppage gait (Bates p. 730) Decreased reflexes may occur Weakness and atrophy of interossei mm. (later stages)

Question 71

Myasthenia Gravis:

Answer 71

``` fatigability, not weakness Autoimmune disorder of neuromuscular junction with antibodies against postsynaptic acetylcholine receptor and disturbed T cell function Common presenting complaint/signs: Fatigue or proximal muscle weakness Droopy eyelids (ptosis) Double vision (diplopia) Trouble swallowing (dysphagia) Trouble speaking (dysarthria) Dyspnea and respiratory muscle weakness (later stages) No sensory loss or altered reflexes. ```

Question 72

screening neurologic exam

Answer 72

The exam should contain assessment of: Mental Status: alertness, appropriate responses, orientation to date and place Cranial Nerves: acuity, pupillary light reflex, eye motion, hearing, facial strength Motor: major muscle group strength upper and lower extremity, gait, coordination (finger to nose) Sensory: test toes/feet – one modality of light touch, pain, temp or proprioception Reflexes: DTR upper/lower, Babinski