Compression Neuropathy DSA Flashcards
What is compression neuropathy?
nerve becomes entrapped as it passes through a narrow tunnel or passage
Where does neuropathy happen?
Any point along a nerve, but there are common sites
What are biomechanical causes of compression neuropathy?
-
Space occupying lesions
- herniated discs & cysts
-
Degenerative causes
- foraminal stenosis
-
Post-traumatic causes
- Fracture
- Hematoma
- Compression from equipment
-
Mechanical
- Muscle spasm
- Pinching from external or positional forces
What are systemic causes of compression neuropathy?
- Pregnancy
- Hypothyroidism
- DB
What is the anatomy of the nerve?
- Epineurium coveres all fasicles, BV and CT
- Perineurium covers fasicles, which contains groups of nerves.
- Endoneurium covers axon + myelin sheath
What pathological changes occur that cause neuropathy?
- Microvascular compression => ischemia
- Thick epineurium
- Thinning of myelin
- Microtubles closure
- Axon degeneration
Sunderland’s classification describes the degree of nerve injury.
What are they?
-
1st degree (neuropraxia)
- Focal damage of myelin fibers around axon, but CT stays intact
-
2nd degree (axonetmesis)
- Injury to the axon, but the myelin sheath is intact
-
3rd degree (neuromesis)
- Damage to axon + endoneurium
-
4th degree (neuromesis)
- Damage to axon + endoneuium + perineurium
- Large amount of scarring at injury, axon does not work distal to injury
- Damage to axon + endoneuium + perineurium
-
5th degree (neuroemesis)
- Damage to axon + endoneuium + perineurium + epineurium
- Hemorrhage and scarring.
- Damage to axon + endoneuium + perineurium + epineurium

What is the recovery seen in all 5 degrees of nerve injury?
- 1st degree: least severe; days- weeks
- 2nd degree: regeneration is possible, but takes months
- 3rd degree: When intraneural fibrosis occurs, regeneration is not possible
- 4th degree: Surgery if no imrpovement to restore neural continuity
- 5th degree: Surgery is NEEDED to restore continuity
Where are 3 places radial nerve can get entrapped?
- High on the humerus, often due to fracture or compression near spiral groove
- Radial tunnel, due to manual labor (rowing, discus, raquet sports) which cuases repetitive rotatory movements
- Wrist
Radial nerve entrapment high on the humerus causes what symptoms
- 1. Wrist drop
- 2. Elbow flexion is weak (brachioradialis m)
- Involve tricep: +/- tricep reflex goes away and pain/numbess
*
- Involve tricep: +/- tricep reflex goes away and pain/numbess
Radial nerve entrapment @radial tunnel causes what symptoms
- Pain and tenderness 5cm distal to lateral epicondyle (elbow)
- Wrist drop
- Pain when supinating
Radial nerve entrapment @wrist causes what symptoms
- Superficial branch (sensory) is pinched in between [brachioradialis and ECRL] when pronating forearm
1. Sensation changes over posterolateral hand when pronating forearm
______ nerve entrapment causes pronator syndrome (pain with resisted forearm pronation & cramping of fingers)
Radial nerve
__________ nerve cause Anterior Interosseous Syndrome.
Median n.
Sx of Anterior Interosseous Syndrome
No sensory symptoms
Testing of Anterior Interosseous Syndrome
•”OK” sign: patient cannot hold and resist tip to tip of the thumb to index pinch
- Index finger’s DIP and the thumb’s IP has a problem flexing

Treatment for Anterior Interosseous Syndrome
Splint elbow in 90 degrees of flexion for up to 12 weeks.
Ulnar Nerve Entrapment is called ____________
Cubital tunnel syndrome
Sx of Ulnar Nerve Entrapment (Cubital Tunnel Syndrome)
- Medial elbow pain that radiates to the hand, causing decreased intrinsic muscle strength => “cant turn a key in a door”
- Paresthesia of 4th/5th finger
How do we diagnose Ulnar Nerve Entrapment (cubital tunnel syndrome)?
- + Tinels sign at elbow
- Symptom reproduce when flex elbow & extend wrist
Ulnar Nerve Entrapment treatment
padded elbow sleeve to limit terminal elbow flexion and provide cushioning
Patient with Cubital Tunnel Syndrome (ulner nerve) will show what sign?
Froment’s sign:
- Task: Pt has to flex thumb to pinch paper between 1st and 2nd fingers
- +: Pt will contract FPL (supplied by median N) bc weak 1st dorsal interosseous and ADP muscles

What is the most common compression syndrome?
Median Nerve Entrapment (Carpal Tunnel Syndrome)
___________ occurs when nerve is compressed as it passes with flexor tendons under the flexor retinaculum
Median nerve entrapment (carpal tunnel)
Sx of carpal tunnel (median n entrapment)
- Nighttime numbness of lateral 3 ½ fingers
- Tingling
- Wrist pain
- Dropping things
- Thenar atrophy
When is median nerve entrapment common?
- Repetitive motion jobs (wrist flexion)
- Pregnancy
Dx median nerve entrapment
EMG (GOLD standard)
What is thoracic outlet syndrome?
Compression of brachial plexus and/or subclavian veins
Thoracic outlet syndrome is the compression of the brachial plexus and/or subclavian veins.
Where does compression occur?
- Scalene triangle
- Costoclavicular passage
- Where pec minor attaches at the coracoid process

Sx of thoracic outlet syndrome
- Weakness
- Parathesia of the medial arm, forearm and hand that is worse when with overhead activities
Tests for Thoracic outlet syndrome?
- Miltary/costoclavicular maneuver
- EAST Test/Roos test
- Wrights HyperABduction test
-
Adson’s test
- + Looking towards arm = Rib 1 is causing compression
- looking away arm = scalene m is causing compression

Compression of __________ causes meralgia paresthetica
Lateral femoral cutaneous N
What compresses the lateral femoral cutaneous N, causing meralgia paresthetica?
Inguinal L at the inguinal canal
What causes meralgia paresthetica?
- Very intense athletics
- Obesity
- Tight girdle/belt, tight clothing
- Seat belt misplacement or post-accident
- Anatomic anomaly (i.e. runs through sartorius)
Sx of Meralgia paresthetica?
- Numbness or burning pain on anterolateral thigh
- Hyperesthesia (increase sensitivity) to the point of not putting anything in pockets
- Trophic skin changes later on
Test meralgia paresthetica?
(+) Tinnel’s sign 1cm medial and inferior to the ASIS
Common fibular nerve compression occurs when ______.
Nerve unwinds around the fibular neckand enters the fibular tunnel

Common fibular N. is supplied by ____
L4-S2
What is the most likely associated finding causing common fibular n. compression?
Posterior fibular head
Causes of common fibular n compression
- Leg hooked over a rail
- •i.e. bedridden, comatose, post-op
- “Strawberry Pickers palsy”
- •Time spent in squatting position
- Ankle sprains or trauma to fibular head
- New meditators (due to lotus position)
- Lithotomy position during childbirth
- Idiopathic
Sx of common fibular n. compression
- Pain on the proximal 1/3 of the lateral leg
- Foot drop
- Sx worse with plantar flexion and inversion of foot
A 21 y/o college cheerleader comes into your office after obtaining an ankle sprain after a dismount during a Saturday football game. She states she has pain along the proximal third of her lateral right leg. When you assess her gate, you notice her steps are louder and make a slapping noise with her right foot. On PE, her symptoms are exacerbated during plantar flexion & inversion of the foot.
Based on this athlete’s findings, which of the following is the most likely associated finding causing her symptoms?
A.Anterior fibular head
B.Posterior fibular head
C.Internally rotated knee
D.Externally rotated knee
What is Tarsal Tunnel Syndrome?
Compression of posterior tibial N. in the tarsal tunnel behind the medial malleolus with the overlying flexor retinaculum

What does the posterior tibial N do?
- Motor: plantar m. of the foot
- Sensation: plantar aspect of foot and toes
What causes tarsel tunnel syndrome?
- 50% = idiopathic
- Other
- Space occuping lesion (synovial cyst, ganglion, tensosynovitis)
- Trauma to medial malleous, distal tibia, calcaneous (MVA)
- Congenital
- AI (RA, ankylosing spondylitis)
- DB
- Standing for too long
Tarsal Tunnel Syndrome Sx
- Pain on plantar aspect of foot
- Non-specific burning, tingling, numbess on plantar aspect of foot
Is gait affected in Tarsel tunnel syndrome?
rarely
Tx tarsel tunnel syndrome
- MFR
- HVLA
- Other: rest, NSAIDS, US, PT, acupunture
Compression of ____________ causes anterior tarsel tunnel syndrome
Deep fibular nerve (L4-S2)
What causes compression of deep fibular N in anterior Tarsal Tunnel Syndrome
Inferior extensor retinaculum
Sx of Anterior Tarsal Tunnel Syndrome
- Pain over dosomedial aspect of foot; worse at REST
- Weak Extensor digitorum brevis

Causes of Anterior Tarsal Tunnel Syndrome
- Trauma (recurrent ankle sprains, soccer players
- Talonavicular dysfunction
- Prolonged plantar flexion (HEELS)
- Compression from shoes
With anterior tarsal tunnel syndrome, ____________ will be weak
Extensor digitorum brevis
New York Giants’ Defensive end, Jason Pierre-Paul (JPP) Comes to you after 4 weeks of having a club cast on his forearm complaining of an abnormal and dull pain in his right arm.
Which of the following findings are you most likely to find?
A. Weakness of the long flexor muscle of the thumb
B. Weakness of the Long Extensor Muscle of the Thumb
C. Weakness of the Abductor muscle of the thumb
D. Weakness of the adduction muscle of the thumb
A. Weakness of the long flexor muscle of the thumb
When Adsons test for Thoracic outlet syndrome is + looking towards affected arm, what is causing compression?
Rib 1
When Adsons test for Thoracic outlet syndrome is + looking away from arm, what is causing compression?
Scalene ms