Test 3- PNS Injuries

Question 1

Motor Nn

Answer 1

• Nn originate from the Ventral Horn and terminate at the end plate of muscle
• MOVE: MOtor, Ventral, Efferent

Question 2

Sensory Nn

Answer 2

• Nn originate from the dorsal root ganglia and terminate as free nerve endings
• SAD: Sensory, Afferent, Dorsal root

Question 3

Layers of Nn

Answer 3

• Epineurium: Outermost layer of Nn. Cushions from eternal pressure and allows movement/motion
• Perineurium Connective tissue that makes up the wall of fascicles
• Endoneurium: Surrounds individual Nn fibers/ supports and protects axons.

Question 4

Mesoneurium function

Answer 4

Slick loose connective tissue that facilitates gliding

-Needed for movement because Nn require mobility- they slide up to 2 cm as we move and often cross jts

Question 5

Ideal conditions for a nerve

Answer 5

Nn need:

• Space
• Movement
• Limited sustained tension

Question 6

Anterograde and Retrograde flow speed

Answer 6

• Anterograde: fast= 400 mm/day, slow= 1-6 mm/day

- Retrograde: 200 mm/day

Question 7

Nutrition used for the Nervous System

Answer 7

• 20% of the oxygen we breath is used by the nervous system

- 20-25% of the calories we consume are used by the nervous system

Question 8

Sensory changes with peripheral nerve dysfunction

Answer 8

• Decreased sensation
• Absent sensation
• Abnormal sensation: allodynia (pain when you shouldn’t feel it), ectopic foci, etc.

Question 9

Autonomic changes with peripheral nerve dysfunction

Answer 9

• Loss of sweating

- Loss of “shunting” from superficial capillaries

Question 10

Motor changes with peripheral nerve dysfunction

Answer 10

• Paresis
• Paralysis
• If denervation: Atrophy of denervation and fibrillations

Question 11

Trophic changes with peripheral dysfunction

Answer 11

• Blood supply changes
• Loss of autonomic innervation
• Loss of sensation
• Loss of movement

Question 12

Neuropathy classified by number of Nn affected

Answer 12

• Mononeuropathy- one N; aka carpal tunel
• Multiple mononeuropathy- several Nn; aka cubital and bilateral carpal tunnel
• Polyneuropathy- many Nn: aka diabetic Nn damage, stocking/glove sensation loss

Question 13

Seddon’s classification of nerve injury

Answer 13

Three degrees of nerve injury:

• Neuropraxia: nerve compression; tingling sensation
• Axonotmesis: traumatic nerve damage; Wallerian degeneration
• Neurontmesis: Severance of Nn

Question 14

Nerve recovery rate

Answer 14

• 1” per month, 12” per year

- 1-2 mm/ day

Question 15

Thoracic Outlet Syndrome

Answer 15

Symptoms arising from the UE, chest (Pec Minor) and neck (Scalenes)
-symptoms produced by positions that compress the brachial plexus and/or subclavian artery/vein

Question 16

Ulnar nerve entrapment

Answer 16

Can become entrapped in either the cubital tunnel (in elbow- “funny bone” pain/sensation) or guyan cannal (in wrist- causes pain in extension and decreased pinch/grip strength)

Question 17

Ortho interventions for ulnar nerve damage

Answer 17

• Cubital tunnel: elbow pad for protection and static night splint with elbow at 35-60 degrees flexion
• Guyon’s canal: neutral wrist splint
• Ulnar nerve palsy: hand splint to block MP hyperextension

Question 18

Sensation impairment from ulnar nerve entrapment

Answer 18

• Sensation is impaired proximally and dorsally with cubital tunnel
• Sensation is impaired only on the volar side with guyan canal

Question 19

Carpal Tunnel Syndrome (CTS)

Answer 19

• Carpal Tunnel houses: median nerve, flexor pollicis longus, and 8 flexor tendons of 4 digits
• Medial nerve is softest and most volar structure so it is very prone to compression
• Leads to (in order): decreased sensation to light touch> hypersensitivity> night pain> paresthesia

Question 20

How does CTS patient present?

Answer 20

• Numbness and night pain
• Paresthesia (numbness/tingling) in medial nerve distribution
• Decrease in pinch and grip strength
• Thenar atrophy in long term cases
• complaints of pain or dropping items

Question 21

Treatment of CTS

Answer 21

• Neutral wrist splint
• Night splint for MP blocking
• AVOID putty squeezing exercises, or full digit flexion grip exercises
• AVOID repetitive or sustained flexion and extension
• AVOID pressure or carpal tunnel

Question 22

Dellon Method for recovery

Answer 22

Based on re-education:

• First goal: re-educate localization of stimulus; stimulate with eyes occluded> if wrong repeat with vision> repeat with vision occlude
• Second goal: recovery of tactile recognition; object identification and tracing of letters/numbers out of sandpaper

Question 23

Pronator Syndrome

Answer 23

• LOOKS LIKE CTS: EMG does not identify it well, often mistaken for CTS
• Tight muscles in the forearms: pronator and FDS
• compression of nerve between two heads of pronator teres: symptoms include weakness in resisted pronation at the medial proximal forearm

Question 24

Splint for pronator syndrome

Answer 24

Splint to prevent pronation and supination as well as wrist flexion and extension
-forearm neutral and elbow flexed at 90 degrees

Question 25

Anterior Interosseous Syndrome

Answer 25

Compression as the nerve penetrates the flexor digitorum profundus in the forearm

• Symptoms include difficulty writing, pain in proximal forearm, and inability to make “OK” sign
• Test by having pt see if they can maintain the “OK” sign

Question 26

Splinting post median nerve damage

Answer 26

• Day splint: C-Bar w/ thumb palmarly abducted

- Night Splint: Web space in full radial abduction

Question 27

Radial Tunnel Syndrome

Answer 27

Compression of the posterior interosseous nerve as it divides and pierces the Arcade of Frohse and compression between the supinator and radial head

• Symptoms: tenderness/pain at the radial head and proximal common extensor muscle bellies
• OFTEN MISTAKEN FOR TENNIS ELBOW