3-9 Exam of the Peripheral Nervous System Flashcards
What are some common complaints that warrant an exam of the PNS?
Shooting pain down entire limb
loss of strength
tingling/parasthesias
chicken pox sequelae
What questions should you ask to help take a good history for a neuro-related complaint?
Local or diffuse?
Restricted to NS (nervous system) or includes other symptoms? fracture, subdural hematoma, tumor growth
CNS, PNS or both
Is your professor a guy named Dr. Vosko?
What is the goal of taking a history with a NS related complaint?
Find where lesion is, then develop good differentials.
What is the scope of the PNS?
Cranial nerves
Motor efferents
Sensory afferents
Neuromuscular junction
Muscle itself
What is the scope of the CNS?
Cortex
Basal Ganglia
Brain stem
Cerebellum
Spinal Cord
Generally, what are the basic parts of the NS exam - history and physical?
¢Central Nervous System
Mental Status and Cognition
Coordination
Cranial Nerves (technically peripheral nerves)
¢Peripheral Nervous System
Motor: Strength and Motion
Sensation
Reflexes
What is the origin and course of the upper motor neurons?
¢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
What is the origin and course of the lower motor neurons?
¢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
What are the most common NS-related complaints?
Pain
Weakness
Paresthesia (numbness/tingling)
What are other important parts of a patient history with a NS-related complaint?
¢Associated Features: swelling, rash, spasm, deformities, mental status
Trauma/Surgery/Medications/Supplements
¢Personal/Family History - autoimmune, dystrophies, diabetes, DJD, exposures
What are the most common causes of NS (nervous system) disorders?
Ischemia (arterial stenosis)
Bleeding (TIA,CVA)
Masses (impingement)
Peripheral nervous disorders (MS, Guillian Barre)
Neuromuscular disorders (myasthenia gravis)
Muscular disorders (dystrophies)
What is dyesthesia?
¢Dysesthesia: all types of abnormal sensation including pain regardless of a stimulant being present or not
Often described by patient
What is a paresthesia?
¢Paresthesia: mostly numb, tingling, pins & needles without pain and without apparent stimulus
What is anesthesia, in the context of an NS exam?
oAnesthesia: absence of senstion
What is hypoesthesia?
¢Hypesthesia or hypoesthesia: reduced sensitivity
What is hyperesthesia?
¢Hyperesthesia: Increased sensitivity
What is hyperalgesia?
¢Hyperalgesia: significant pain in response to mildly painful stimulus (sharp)
What is allodynia?
¢Allodynia: non-painful stimulus perceived as painful on the skin, sometimes severe
What are the 5 types of sensation tested in a PNS exam?
Spinothalamic:
¢Pain: pin or sharp end of broken Q-Tip
¢Temperature: Metal hammer handle is cool
¢Light touch: Q-Tip Cotton wisp
Posterior Column:
¢Proprioception (Position): Large Toe: up? down?
¢Vibration: Tuning fork on boney prominence
In addition to types of touch, what 3 other things should be done when testing sensation in a PNS exam?
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
What is being tested during a discriminative sensation exam?
Test of cortical sensory function
¢Stereognosis: Identify an object by feel
¢2-point discrimination
¢Number Identification: Identify shapes/numbers
What 4 things should be tested with a motor exam? On what side should testing be done?
¢Inspection: atrophy
¢Palpation: tone, soft, firm. Spasm?
¢Strength testing: major muscle groups
¢Reflexes: brainstem, superficial, deep, clonus
Testing should always be done bilaterally
What is the scale for muscle strength? What is the scale relative to?
¢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
Relative to patient’s full, non-pathological strength
Examine and compare bilaterally
How is muscle strength named?
¢Name for joint motions or muscle group
“4/5 left bicep” or “4/5 flexion at left elbow”
What are some DTRs that are commonly tested? How are they tested and what do they signify?
¢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
What is the grading scale for DTRs?
¢0 = Absent ¢1+ = Diminished ¢2+ = Normal/Average ¢3+ = Mildly over-active ¢4+ = Highly over-active
How does reinforcement work in regards to DTRs?
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.
What are hallmark symptoms of an UMN (upper motor neuron) lesion?
Upper Motor Neuron Lesion
vSpasticity is hallmark (not 100%)
vLoss of dexterity
vUp Going Babinski (abnormal)
vLoss of superficial reflexes
vWeakness without atrophy of muscle
vHyperreflexia of deep tendon reflex (DTR)
¢Paralysis of movement, not muscle
¢Atrophy from disuse, slight
¢Spasticity, hypertonic
What are some common causes of UMN lesions?
Stroke
Multiple Sclerosis
Cerebral Palsy
Traumatic Brain Injury
Amyotrophic Lateral Sclerosis
What are some hallmark symptoms of an LMN (lower motor neuron) lesion?
Lower Motor Neuron Lesions
Flaccid paralysis
Muscle atrophy/wasting
Hyporeflexia
¢Paralysis from muscle atrophy
¢Wasting pronounced
¢Flaccid, hypotonic
¢DTR low or absent
What are some common causes of LMN lesions?
Polio
Guillain-Barre
Amyotrophic Lateral Sclerosis (ALS)
What are some common PNS disorders?
Polio, Amyotrophic Lateral Sclerosis
- Herniated Disc
- Carpel Tunnel Syndrome, Bell’s Palsy
- Diabetes, Alcoholic Neuropathy
- Myesthenia Gravis
- Muscular Dystrophy
What can affect the anterior horn of the spinal cord? What symptoms will present?
¢Anterior Horn Cell: Polio, Amyotrophic Lateral Sclerosis (ALS)
Fasciculations and weakness in a segmental pattern
Sensation intact (why?)
Weak DTR
What are fasciculations?
Fasciculations: small, local contractions seen thru the skin. Typically rapid, and from a single motor nerve filament
What commonly affects spinal nerve roots? What are the symptoms? Why is it so painful?
¢. Spinal nerve roots: Herniated disc
Dermatomal Sensory Changes
Weakness ⇨ Atrophy
•Weak DTR
Spinal nerve is very short, 5 mm, just where the sensory and motor nerve tracts merge. Intractable pain and weakness or atrophy make it surgical to treat
Pops posteriorly catching sensory tracts most.
What are some common symptoms of peripheral mononeuropathy? Symptoms?
¢Peripheral mononeuropathy: Carpal Tunnel Syndrome, Bells Palsy
Weakness and sensory loss in that peripheral nerve distribution
Weak DTR
What are some common causes of peripheral polyneuropathy? Symptoms?
¢Peripheral polyneuropathy: Diabetes, Alcoholic Neuropathy
Distal weakness and stocking-glove distribution sensory loss
Weak DTR
What is a common cause of pathology at the NMJ? Symptoms?
¢Neuromuscular junction: Myasthenia Gravis
Muscular fatigability
Sensation intact
DTR intact
What are some common causes of NS-related muscle pathology? Symptoms?
Muscle: Muscular Dystrophy
Weakness primarily in proximal muscles
Sensation intact
DTR intact or possibly decreased
What are the causes of thoracic outlet syndrome?
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.
What are the results of thoracic outlet syndrome?
Results: Weakness and numbness of the hands and arms due to compressed neurovascular supply.
How do you test for thoracic outlet syndrome?
Roo’s Test
Adson’s Test
What can cause an upper brachial plexus injury? What is damaged?
Stretching of the neck away from the shoulder
Often due to birth trauma or falling
Damage to C5 C6 nerve root motor and sensory most common
What position is the arm held in with an upper brachial plexus injury?
Waiters Tip position commonly seen.
What can cause a lower brachial plexus injury?
¢The arm being pulled superiorly
Catching something overhead
Birth trauma (pulling out by the arm)
¢Thoracic outlet syndrome
¢C8,T1 motor palsy/weakness
What is the cause and the result of an injury to the long thoracic nerve?
¢Causes
Compression between clavicle and 1st rib
Axillary surgery
¢Results
Damage in C5-7 region
Weak Serratus Anterior m. (winging of the scapula)
What are some causes of injury to the median nerve?
¢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
What are some test for carpal tunnel syndrome?
¢Tinels sign
¢Phalens test
¢Reverse Phalens (Prayer Test)
What are the results of an injury to the median nerve?
¢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
What is the test for pronator syndrome (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)
What are the causes of an anterior interosseus neuropathy of the median nerve?
¢Causes:
Pronator teres impingment of Anterior Interosseus N.
Trauma; Tennis Elbow strap too tight
What is the result of an anterior interosseus neuropathy (median nerve)?
¢Results:
Weak flexor digitorum profundus & flexor pollicis longus
What is the test for an anterior interosseus neuropathy?
¢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
What are some common causes of an ulnar nerve injury?
¢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
What is the result of damage to the C6-C8 region?
¢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
What muscle deficits create claw hand?
¢CLAW HAND
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)
What are some causes of radial nerve injury?
Fracture of the humerus near the radial groove
“Saturday Night Palsy” compression by sleeping with arm under head
What are some results of a radial nerve injury?
Damage in the C7-T1 region
Sensory loss to the back of the hand
Wrist Drop - Weak brachioradialis, supinator, wrist & digit extensors
What is a test for cubital tunnel syndrome?
¢Tinels sign (at the elbow)
“Funny Bone”
What are some causes of sciatic nerve injury?
¢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
What are the results of a sciatic nerve injury?
¢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
What is the result of a superior gluteal nerve injury?
¢Results
TRENDELENBURG GAIT- weak hip abductors and external rotators (gluteus medius)
Weak gluteus medius on standing side: cannot hold the opposite hip level.
What are some causes of a lateral femoral cutaneous nerve injury?
Compression at the iliac crest (belts, seats, large bellies)
What are the results of an injury to the lateral femoral cutaneous nerve?
Numbness over the lateral thigh
What are some causes of common fibular/peroneal nerve injury?
¢Causes
Impingement by piriformis (sciatic n.)
Proximal fibular fracture
Stretched from a varus stress (with lateral collateral ligament )
Compressed by casting
Surgery
What are the results of a common fibular/peroneal nerve injury?
¢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
What are some common causes of a superficial fibular nerve injury?
¢Causes
Proximal fibular fracture
Stretched with varus stress
Compressed by casting
Surgery
What are the results of a superficial fibular nerve injury?
¢Results
Paralysis of foot everters; NO foot drop
Loss of sensation of the anterolateral leg and dorsum of the foot
What are some causes for deep fibular nerve injury?
¢Causes
Anterior Compartment Syndrome
Anterior Tarsal Tunnel Syndrome
Pes Cavus (high arch)- less space under the retinaculum
Tight shoelaces
Trauma
What is the result of a deep fibular nerve injury?
¢Results
Weak dorsiflexors
FOOT DROP
What are the causes and results of a medial plantar nerve injury?
¢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
What is the result of diabetic peripheral neuropathy?
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)
What percentage of patients with DM will develop diabetic peripheral neuropathy?
¢Diabetic Peripheral Neuropathy
Estimated 42% of DM patients will develop neuropathy 10 years after diagnosis.
What are the common symptoms of myasthenia gravis?
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.
What are the 5 components of a screening neurological exam?
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
