Upper Limb Nerve Injury Flashcards
1
Q
Between which points in the nerve tract would cause LMN condition?
A
- anywhere between the Motor cortex in the brain to the lower motor neuron in the anterior horn of the spinal cord
2
Q
What are the different signs seen in UMN and LMN lesions?
A
Upper Motor Neuron
- Held in flexed posture if chronic.
- Increased tone
- Pyramidal weakness (Flexor muscles stronger than extensors)
- Brisk reflexes.
- a clear demarcation of sensory changes
Lower Motor Neuron
- Wasting/Fasciculations
- Flaccid tone
- Weakness in either a myotomal distribution or a peripheral nerve distribution
- Reduced reflexes.
- Dermatomal or peripheral nerve distribution of sensory loss.
3
Q
What are Myotomes and Dermatomes
A
- Myotomes - Relationship between the spinal nerve & muscle
- Dermatomes - Relationship between the spinal nerve & skin
4
Q
What is this an image of?
- which dermatomes are affected?
A
- Herpes Zoster
- Goes to the V1 branch of the Trigeminal Nerve (CN V)
- T4 and T5 in the rips
5
Q
What are the myotomes of C5-T1
- what are their respective muscle actions?
A
6
Q
What reflexes are associated with spinal roots C5-C8?
- what is the clinical significance?
A
- Biceps reflex – C5 reflex conveyed through the musculocutaneous nerve.
- Supinator jerk – C6 reflex conveyed through the radial nerve.
- Triceps jerk – C7 reflex conveyed through the radial nerve.
- Finger jerk – C8 reflex conveyed through the median and ulnar nerve.
In low motor lesions the reflex is depressed
7
Q
What is a nerve Impingement and what are the causes?
- what does the result of the impingement?
A
- when a nerve is trapped/ compressed
Causes
- slipped disk/ herniation - causes nucleus pulposus to herniate into the spinal canal compression the nerves
Results in
- pain on the neck - which radiates/ aggravated by neck movement
- sensory loss
- weakness
- loss of reflexes
8
Q
What type of imaging is this and what does it show?
- what is the weighting/ plane
- what is the effect of the pathology shown?
A
- T2 weighted MRI, coronal view
- shows herniated disk C6 disk causing root nerve impingement
can cause a Cervicoradicular Myelopathy (root= radiculopathy, spinal cord=mylopathy)
- there may be no motor neuron signs at the level the root is pressing on as it exits the spinal cord
- but it’s also pressing the spinal cord so you get upper motor neuron signs below that
9
Q
What are different types of Nerve plexus injuries?
- what are their corresponding repairs?
A
- Avulsion: Tearing of the nerves from its attachment at the spinal cord. – Require surgical repair
- Rupture: Tearing of the nerves but not from its attachment to the spinal cord – Require surgical repair
- Neuroma: tumour or growth of the nerve tissue. Can arise from the axon or myeloma – Require surgical repair
-
Neurapraxia: Axons remain intact, but myelin damage causes an interruption of the impulse down the nerve fibre – Good prognosis.
- it is intact so better recovery
10
Q
What pathology is seen in this image?
- what are the consequences of this pathology to other structures?
A
- C5-T1 lesions causing flail arm
- cervical root avulsion
- Left shoulder subluxation
- Atrophy of the left deltoid, supraspinatus and infraspinatus
11
Q
What are the causes of Brachial plexus Injury?
(4 main groups)
A
- Trauma
- Erb-Duchenne type paralysis: Avulsion of C5,C6 roots.
- Klumpke paralysis: Avulsion of C8, T1 roots.
- Cancer
- Lung cancer: Pancoast’s tumour
- Radiotherapy
- Inflammatory
- Brachial neuritis
- Structural
- Thoracic outlet syndrome
12
Q
What is Erbs palsy (Erb-Duchennetype paralysis)?
- What is the cause
- what is the effect on other structures?
A
- Avulsion of C5, C6 roots
- Usually caused during parturition or as a blow to the shoulder in adults
causes weak muscles in the following
- Biceps (flexes the arm)
- Brachioradialis (flexes the arm in semi-prone position)
- Deltoid (abducts the arm)
- Supraspinatus (abducts the arm)
- Supinator (externally rotates the arm)
the arm doesn’t work but the hand does
13
Q
What is Klumpke’s Palsy?
- What is the cause
- What is the effect on other structures?
A
- Inferior trunk plexus injury involving Avulsion of C8/T1
- Clutching for an object when falling from a height, at birth when pulled with the arm in a breach delivery
- Involves trunk that supplies median and ulnar nerves
- Unable to flex wrist or fingers
- Weakness of all small muscles of the hand
- Sensory loss hand and inner border of the forearm
- May lead to a claw hand
- Arm works but hand does not!
14
Q
What is Pancoast Tumour?
- What is the neurological effect of this tumour
- What are further implications of treating the tumour?
A
- An apical lung cancer close to the inferior brachial plexus
- the tumour can infiltrate into the lower brachial flexus
- effects the arm but the hand works
- Pain in the shoulder girdle and inner arm
- Ipsilateral horners syndrome
Can also experience radiation-induced brachial plexopathy
- experienced 6 yrs post radiation
- associated with treatment for breast, lung cancer and lymphoma
- pain is not a consistent feature
15
Q
What is radiation-induced Brachial plexopathy
A
- experienced 6 yrs post-radiation treatment
- associated with treatment for breast, lung cancer and lymphoma
- pain is not a consistent feature
16
Q
What is Ipsilateral horners syndrome?
- cause
- symptoms
A
- An interruption of nerve supply from the brain to the face and eye, on one side of the body.
- Usually caused due to injury to the spinal cord, stroke, tumour or underlying conditions.
- Symptoms: small pupils (miosis), little or no sweating on the affected side, drooping of the eyelids and unequal pupils.
22
Q
what is the supply of the long thoracic nerve?
How can the Long Thoracic Nerve be damaged?
- what pathology does this result in? and why?
- how can damage be tested
A
- blows or pressure to the posterior triangle of the neck
- damaged during a radical mastectomy
- leads to a winged scapula
- Long thoracic nerve supplies the serratus anterior muscle.
- The serratus anterior muscle pulls the medial border of the scapula to the posterior thoracic wall and stabilises it there
- Impairment of the long thoracic nerve leads to “winging” of the scapula
- pushing against a wall causes the scapula to wing out
28
Q
How is sensory innervation of the median nerve impacted depending on where the lesion is?
A
- if the lesion is more distal there is greater sensory and motor disfunction
- one of the sensory branches of the median nerve decussates earlier on
30
Q
What are two key branches of the ulnar nerve and how are they clinically significant?
A
32
Q
What sign indicates Ulnar n. palsy?
- what is the biomechanics behind this?
A
- Froment’s sign
- Ulnar nerve supplies the Ulnar nerve abductor pollicis causes this
33
Q
How do you distinguish between Ulnar lesion vs a C8 lesion?
A
motor examination exam
- C8 supplies
- all finger extensors - radial nerve so a finger extension would be effected
- Flexor Digitorum Profundus of index/ middle finger- median nerve
- Radial nerve palsy (extenders effected) - flappy wrist
- Numbness in the region of the anatomical snuffbox indicates radial nerve damage
35
Q
What does a nerve conduction study do?
- what two conditions can it identify
A
- determines the amplitude and velocity along peripheral nerve
- Demyelinating conditions- slower velocity
- Axonal loss - decrease in amplitude
36
Q
What does a Needle EMG measure?
- what two pathologies can it distinguish between?
A
- measures the electrical activity of the muscle during voluntary contraction.
- The pattern of the electrical activity can help distinguish a lesion arising from the nerve (neurogenic) vs muscle (myopathic)
