entrapment neuropathy-bennet

Question 1

compression injury, resulting in myelin sheath degeneration. there is conduction deficit WITHOUT axonal destruction

Answer 1

neurapraxia

Question 2

Axonal and myelin sheath disruption without disruption of endoneurial tube

Answer 2

Axonotmesis

Question 3

endogenous etiology of peripheral neuropathy

Answer 3

compartment syndrome-edema of the fascical compartment of the leg/foot leading to nerve compression that will cause NERVE INFARCTION

(so much edema compression on vasculature where it causes internal damage to nerve) —>nerve infarction

intraneural hematoma-direct nerve contusion or from injection cause INTRANEURAL bleeding and COMPRESSION (can cause vessel breakage–>cause nerve death)

Question 4

what nerve is compressed when there is a burning sensation over anterolateral thigh under the inguinal ligament

Answer 4

Lateral cutaneous nerve of thigh

Question 5

which nerve is involved with anterior tarsal tunnel? where does entrapment occur?
site of injury?

what are the two terminal branches of this nerve?

Answer 5

deep peroneal nerve: L4-S1: medial and lateral

entrapped in the anterior ankle and dorsum of the foot’

just distal to the ankle: site of injury: compression for overactive extensor digitorm brevis

Question 6

where is the intermetatarsal neuroma located? and nerve does this involve

Answer 6

commonly in the 3rd intermetatarsal space. typically occurs here because medial and lateral plantar nerve contribute branches to this space

Question 7

what test can you order to determine if its a neuroma or neuritis

Answer 7

MRI

Question 8

what test is used to test for the posterior tibial nerve involvement injury

Answer 8

tourniquet test

Question 9

what test is essential to evaluate for nerve edema or enlargement

Answer 9

MRI

Question 10

Saphenous nerve entrapment
spinal level?

where does this occur?

Answer 10

L3,L4

occurs in patients with genu valgum (knock knee)–this could put strain on nerve

can be entrapped from a contusion at medial malleous
can be injured during ankle arthroscopy:medial malleolus

Question 11

Common peroneal nerve spinal level?

symptoms?

site of entrapment?

Answer 11

L4,L5,S1

pain and paresthesias over lateral leg and dorsum of foot with weakness in dorsiflexion of foot

-nerve is compressed at the fibular neck
injury leads to weakness of tibialis anterior and resultant foot drop

causes: cast pressure, bed ridden, high fibular fracutres, crossing legs

Question 12

Superficial peroneal nerve spinal level
area of injury

cause of entrapment

Answer 12

L4 L5 S1

repeated micro-compression that cause intra and perineural fibrosis that can entrap axonal tissue

2 branches:
medial dorsal cutaneous nerve entrapped from compression,

intermediate dorsal cutaneous nerve entrapped from tight shoes

high arches have risk for compression

Question 13

spinal levels for sural nerve? what does it become?

site of injury of compression?

Entrapment site?

Answer 13

sural nerve becomes the lateral dorsal cutaneous nerve

site of injury:

sural: lateral posterior leg from chronic tendonitis of achilles compressed

Lateral dorsal cutaneous nerve: foot entrapped following 5th metatarsal fracture

entrapped in scar tissue following achilles or lateral ankle surgery

Question 14

what structures are in the tarsal tunnel? what can cause compression entrapment?

spinal levels involved?

Answer 14

Tibial nerve: L4,L5, S1,S2,S3

4 structures: tibialis anterior, flexor digitorum longus, Tibial nerve and vessels, flexor hallucis longus

tom, dick and very nervous harry

injury to any structures in this compartment can put pressure on nerve

positive tinel and villioux sign

Question 15

what is the most common entrapment neuropathy in foot

Answer 15

morton’s neuroma

Question 16

signs of morton’s neuroma

Answer 16

numbness tingling to 3rd and 4th toes with pinching pain under the ball of the foot

positive mulders click to the 3rd interspace: squeeze foot–>compress nerve between 3rd and 4th metatarsal produces a “click”

Question 17

compression of subclavian artery and brachial plexus: cyanosis of fingers, weakness of shoulder and arm

Answer 17

thoracic outlet

Question 18

compression on the median nerve can cause sensation distrubance and weakness of the medial 3 fingers.

positive tinel sign

Answer 18

carpal tunnel syndrome

Question 19

where is does the medial plantar nerve entrapment of tibal nerve occur?

where does the lateral plantar nerve entrapment of tibial nerve?

Answer 19

abductor canal: medial plantar nerve entrapment

Plantar vault: lateral plantar nerve entrapment

Question 20

Villoux sign

Answer 20

tapping directly over nerve causing radiating sensation in both proximal and distal

Question 21

what compresses on the posterior tibial nerve? and what can test this?

Answer 21

vena comitans: tourniquet test, used for posterior tibial nerve involvement

Question 22

what is the goal to tx entrapment

Answer 22

inflammation: use steroid injection

Question 23

what is essential to evaluate entrapment

Answer 23

MRI

Question 24

how do we treat vena comitans

Answer 24

compression stocking, surgical ligation