T4 Test 2 Flashcards
This is the least severe form of nerve injury, temporary impairment of condition. With no significant structural change of the cell and no wallerian degeneration.
Neuropraxia
What are some causes of neurapraxia?
Mild compression injury e.g Saturday night palsy, and other entrapment neuropathy, leading to mechanical deformation of the nerve and or ischemia.
What is the prognosis of neuropraxia?
Axonal conduction and function is usually restored completely once cause of compression is identified and addressed
May need an interval of rest
May occasionally leave mild permanent damage 
What is axonotmesus?
Loss of axonal structural continuity, no loss of continuity of the Endoneurial sheath with wallerian degeneration.
What are some causes of axonotmesis?
- Can be a result of a more severe impact or stronger/more sustained compressive situation
- Neuritis, infection (Lyme, disease, toxins, diabetes related ischemia)
- Can also occur when the nerve is stretched
What is the prognosis of axonotmesis?
- may recover completely, but some degree of permanent damage is likely. affected axons may regenerate
- requires period of immobilization or modified use
- treatment according to cause possibly anti-inflammatories
Separation of the axon and damage to connective tissue. The injury may be a complete transection, proximal and distal segments or part of the nerve may remain in continuity. There is Wallerian degeneration. This is…
Neurotmesis
What are causes of neurotmesis?
Severance injuries, displacing fractures and ruptures/traction injuries. Also amputations crush injuries, industrial accidents, MVAs
Includes damage to endoneurium perineurium, and in the most severe cases the epineurium may lead to neuroma formation
What is the prognosis of neurotmesis?
- In cases involving viable distal segments, complete recovery is hypothetically possible, but unlikely. axons must regenerate
- Usually partial recovery or permanent complete loss of function
- Surgical repair, nerve graphs often required
- Immobilization often for 3 to 6 weeks and rehab required
List the connective tissue layers of the axons from outermost to innermost.
Epineurium, Perineurium, Endoneurium
What is wallerian degeneration?
The process that occurs when axon/nerve fibre is cut, severely tractioned or crushed. Which occurs in 4 stages (Degeneration, Clearance, Regeneration, Growth & re-myelination)
What is neurolemma?
Infiltration by macrophages, mast cells and Schwann cells to clear fragmented, axonal material and debris from the injury site and along the pathway of the axon
The _____ is essential for regeneration of a peripheral nerve. It should remain as a hollow tube after clearance stage to move to the regeneration stage.
Endoneurial sheath
GAP repair on average tends to last _____ days
10 to 12
Regeneration is said to occur on average at a rate of ____ per day
1 mm per day
What is neuroma?
Regenerating axons wander into surrounding tissue/scar and form, dense fibrous mass of scar tissue made up of disorganized Schwann cells, capillaries, fibroblast, macrophages, and collagen fibres at the injury site
What is neuritis?
Inflammation of a nerve
What is the regeneration frontier?
The regeneration frontier is the location of the leading tip of the new axon, It’s newly reconstructed, neurolemma and Myelin sheath during regeneration.
What can be used to locate the regeneration frontier?
Tinel’s sign
What is flaccid paralysis?
Atonia - full loss of firing
What is flaccid paresis?
Hypotonia - partial loss of firing
A partial injury is more likely to present with…
Irritable firing phenomenon
What is hyperesthesia?
Increased sensitivity to stimulation
What is paresthesia?
Spontaneous, abnormal sensations
What is dysesthesia?
Unpleasant, painful sensations
What is allodynia?
Pain caused by stimulus that doesn’t usually provoke pain.
What is hyperalgesia?
Increased pain response to a stimulus that is normally painful
What is hyperpathia?
Increased sensory threshold for stimulus, but more intense and prolonged pain once threshold is reached
Which nerves carry the majority of the autonomic axons for the entire limb, upper and lower?
Median for upper
Tibial/sciatic for lower
What muscles are innervated by the axillary nerve?
Deltoids
Teres minor
(Long head of triceps brachii)
Where is the sensory innervation of the axillary nerve?
To the superolateral shoulder over deltoid
(Skin over the shoulder)
What are the motor functions of the axillary nerve?
Abduction of the arm beyond first 15°
What mm are innervated by the musculocutaneous nerve?
- BBC = Biceps, Brachialis, Coracobrachialis
What are the motor functions of the musculocutaneous nerve?
- Flexion of the arm at the elbow
- Supination of the forearm 
What is the sensory innovation of the musculocutaneous nerve?
The lateral forearm
Which upper limb nerve is most commonly affected by diabetic neuropathy?
Musculocutaneous nerve
Loss of biceps DTR may be from injury to which nerve?
Musculocutaneous
Which muscles are innovated by the median nerve?
Flexor carpi radialis, Palmaris longus, pronator quadratus, pronator Teres, digital flexors
What are the motor functions of the median nerve?
Thumb flexion and opposition, flexion of digits 2 & 3, wrist flexion and abduction, forearm pronation
What is the sensory innervation of the median nerve?
Skin over anterolateral surface of hand
What is carpal tunnel syndrome?
Compression of the median nerve as it passes through the carpal tunnel beneath the transverse carpal ligament.
Is forearm pronation a sole or shared action of the median nerve?
Sole action
Is wrist flexion a shared or sole action of the median nerve?
Shared with ulnar
Is wrist abduction a shared or sole action of the median nerve?
Shared with radial
Is thumb opposition a shared or sole action of the median nerve?
Shared with ulnar
Is thumb abduction a shared or sole action of the median nerve?
Shared with radial
Which actions of the median nerve are shared with the ulnar nerve?
Wrist flexion, thumb flexion, finger flexion of fingers four and five
Which actions of the median nerve are shared with the radial nerve?
Wrist abduction, thumb flexion
Which nerve carries majority of autonomic fibres for the entire arm, forearm and hand
The median nerve
Which nerve is referred to as the tool utilization nerve?
The median nerve
Full loss of medium nerve function leads to _____ deformity
Ape hand deformity
Which mm are innervated by the ulnar nerve?
Flexor carpi ulnaris, flexor digitorum profundus, adductor pollicis, small digit mm
What are the motor dunctions of the ulnar nerve?
Finger adduction and abduction other than thumb, thumb adduction, flexion of digits 4 and 5, wrist flexion, and adduction
What is the sensory innervation of the ulnar nerve?
Skin over medial surface of the hand through the superficial branch
Arcade of Struthers entrapment is entrapment of which nerve?
Ulnar nerve
Cubital tunnel syndrome can affect which nerve?
Ulnar nerve
Full loss ulnar nerve function leads to reduce grip strength and ____ presentation
Claw hand
Compression in the arcade of froshe is a common injury of which nerve?
Arcade of froshe
True or false: it is possible to get i juries to the radial nerve that are sensory only or motor only
True: this is because motor and sensory branches of the radial nerve take different paths in the forearm
What mm are supplied by the radial nerve?
- Forearm extensors
- Triceps, brachioradialis, extensor carpi radialis longus, anconeus
