Upper limb nerve injuries Flashcards
What is the corticospinal tract (CST), also known as the pyramidal tract?
- a collection of axons that carry movement-related information from the cerebral cortex to the spinal cord
- relate to voluntary movement
The corticospinal tract (CST), also known as the pyramidal tract is a collection of axons that carry movement-related information from the cerebral cortex to the spinal cord. Is this an ascending or descending tract?
- descending tract
- carries instructions from motor cortex to spinal cord
What is the definition of an upper and lower motor neuron?
- UMN = begin in the cerebral cortex and end in brain stem or spinal cord
- LMN = begin in spinal cord or brain stem and end at target tissue
The corticospinal tract (CST), also known as the pyramidal tract is a descending tract of a collection of axons that carry movement-related information from the cerebral cortex to the spinal cord. Where do these synapse in the spinal cord and is this efferent or afferent?
- synapse at ventral/anterior horn
- efferent as they are effector neurons
The upper motor neurons of all cranial nerve of the brain (except CN I and CN II) synapse where?
- brain stem
The upper motor neurons of all cranial nerve of the brain (except CN I and CN II) synapse at the brainstem. Where do CN I (olfactory) and II (optic nerve) come from?
- cerebrum
The brainstem is composed of 3 major parts, the midbrain, the pons and the medulla. Using football formation of 4-4-2, working inferior to superior, which upper motor neurons of which cranial nerves synapse at the medulla of the brainstem?
- 4 in total
- CN IX (9) glossopharyngeal
- CN X (10) vagus nerve
- CN XI (11) accessory nerve
- CN XII (12) hypoglossal nerve
The brainstem is composed of 3 major parts, the midbrain, the pins and the medulla. Using football formation of 4-4-2, working inferior to superior, which upper motor neurons of which cranial nerves synapse at the pons of the brainstem?
- 4 in total
- CN V (5) trigeminal nerve
- CN VI (6) abducens nerve
- CN VII (7) facial nerve
- CN VIII (8) vestibulocochlear nerve
The brainstem is composed of 3 major parts, the midbrain, the pins and the medulla. Using football formation of 4-4-2, working inferior to superior, which upper motor neurons of which cranial nerves synapse at the midbrain of the brainstem?
- 2 in total
- CN III (3) oculomotor nerve
- CN IV (4) trochlear nerve
Once an upper motor neuron (UMN) travels down the corticospinal tract (pyramidal, voluntary movement tract) it synapses at the ventral/anterior horn of the spinal cord or brain stem. What lower motor neuron will the UMN synapse with to elicit voluntary movement?
1 - gamma motor neuron
2 - beta motor neuron
3 - beta 1a motor neuron
4 - alpha motor neuron
4- alpha motor neurons
- allow us to contract skeletal muscle
Once an UMN synapses with the alpha motor neuron, a LMN in the spinal cord or brainstem receives information to initiate an action. What modulates this to ensure we don’t over contract?
- proprioceptors through gamma motor neurons
- feedback through muscle spindles and golgi tendon organs
- ensure the muscle is not damaged
How do UMN and LMN lesions affect the reflexes ?
- UMN = brisk reflexes
- LMN = reduced reflexes
How do UMN and LMN lesions affect the muscle strength?
- UMN = reduced strength (no message getting to muscles)
- LMN = proximal weakness
How do UMN and LMN lesions affect muscle tone ?
- UMN = increased tone
- LMN = reduced tone
In an UMN lesions there is pyramidal weakness. What is this?
1 - unaffected
2 - flexors become stronger than extensors
3 - extensors become stronger than flexors
4 - complete loss of flexion and extension
2 - flexors become stronger than extensors
- rubrospinal tract facilitates flexion and inhibits extension
- reticulospinal tract can inhibit alpha and gamma motor neurons, thus fine tuning the movements, including balancing between flexion and extension
- in UMN the reticulospinal tract is lost so rubrospinal tract takes over, hence weaker in extension compared to flexion
How do UMN and LMN lesions affect the sensations?
- UMN = cortical sensations are lost
- LMN = peripheral sensations are lost
In addition to the corticospinal tract (pyramidal) there is another tract that also synapses with at the ventral (anterior) horn of the spinal cord. This is really important for doing what with the alpha and gamma motor neurons?
1 - inhibit gamma neurons only
2 - inhibit alpha neurons only
3 - fine tuning alpha and gamma neurons to fine tune them
4 - inhibiting alpha and gamma neurons altogether
3 - fine tuning alpha and gamma neurons to fine tune them
- this inhibition is fine tuning to ensure control and balance, NOT stopping alpha and gamma motor units altogether
The Reticulospinal Tract works closely with the corticospinal tract (pyramidal), synapsing with the ventral (anterior) horn of the spinal cord. The reticulospinal tract inhibit alpha and gamma motor neurons, thus fine tuning movements and balance. If there is a UMN lesion this inhibition is lost. What can this do to muscle tone and reflexes?
1 - increased reflexes with loss of tone
2 - increased reflexes with increased tone
3 - loss of reflexes and tone
4 - loss of reflexes with increased muscle tone
2 - increased reflexes with increased tone
- increased muscle tone as no inhibition of alpha motor units
- increased reflexes as no inhibition of gamma motor units
What is the difference between spasticity and rigidity?
- spasticity = velocity dependent (increased speed = increased tone) and only in one direction (flexor)
- rigidity = not velocity dependent and the same in both directions (flexion and extension for example)
Which nerve roots innervate the upper limbs?
- C5-T1
In terms of nerves, what does a dermatome relate to?
- a specific nerve root supplying a region of the skin and its senses
In terms of nerves, what does a myotome relate to?
- 1 nerve root supplying motor function to a muscle
If a nerve root is damaged, is this classed as peripheral nerve damage?
- no
- the peripheral nerve has not formed yet
Match the nerve roots with the muscle group and movement:
- C5, C6, C7, C8, T1
- Deltoid, Biceps, Triceps, Forearm extensors, Deep forearm flexors, Intrinsic muscles of the hand
- Shoulder abduction, Elbow flexion, Elbow extension, Wrist extension, Wrist flexion
Finger extension, Finger flexion, Finger abduction
- C5 = deltoid muscles and shoulder abduction
- C6 = biceps, elbow flexion
- C7 = triceps, superficial forearm flexors and extensors, elbow extension
- C8 = forearm extensors and deep forearm flexors, finger extension and flexion
- T1 = intrinsic muscles of the hand, finger abduction
There are 3 key reflexes in the upper limb. Match the reflex with the nerve root below:
biceps reflex ((musculocutaneous nerve)) triceps reflex (radial nerve) supinator reflex (radial nerve)
C5, C6 or C7
- biceps reflex = C5 (musculocutaneous nerve)
- supinator reflex = C6 (radial nerve)
- triceps reflex = C7 (radial nerve)
When eliciting the supinator reflex, supplied by C6 (radial nerve), where should we be looking for the reflex?
- near the elbow as its really brachioradialis reflex
If there was a nerve root problem that damaged C7, what myotome and dermatome would be affected?
1 - bicep flexion and sensation in thumb will be lost
2 - tricep extension and sensation in middle finger on dorsal surface will be lost
3 - bicep flexion and sensation in middle finger will be lost
4 - tricep extension and sensation in thumb will be lost
2 - tricep extension and sensation in middle finger on dorsal surface will be lost
The axillary nerve originates from C5 and C6 nerve roots. Which cord of the brachial plexus does it originate from?
1 - anterior
2 - posterior
3 - middle
All are the brachial plexus position relative to the axillary artery
2 - posterior
- which means it is behind the axillary artery
Which muscles does the axillary nerve innervate?
1 - deltoid, teres major and long head of the triceps
2 - deltoid, teres minor and long head of the triceps
3 - deltoid, teres minor and biceps brachii
4 - trapezius, teres minor and biceps brachii
2 - deltoid, teres minor and long head of the triceps
What particular space does the axillary nerve pass through?
1 - quadrangular space
2 - triangular space
3 - hiatus space
4 - cuboidal space
1 - quadrangular space
- also contains the posterior circumflex artery
What is the most common injury associated with damaged to the axillary nerve?
1 - fractured clavicle
2 - fractures surgical neck of humerus
3 - fractured humeral head
4 - shoulder dislocation
4 - shoulder dislocation
What would damage to the axillary nerve cause to the motor and sensory function?
- motor = loss of shoulder abduction
- sensory = lateral upper arm, where badge of honour would be placed (NOT dermatome, but cutaneous)
If someone has a dislocated shoulder and you suspect the axillary nerve is damaged what must you do prior to putting the shoulder back in?
- CHECK MOTOR AND SENSORY BEFORE ANY TREATMENT
- motor = assess shoulder abduction and flexion
- sensory = assess sensations over regimental badge area (lateral aspect upper arm)
Damage to the musculateaneous nerve is rare and is most commonly caused during surgery. If this is damaged what motor and sensory tests can we perform?
- motor = flexion of elbow and supination of the forearm
- sensory = lateral cutaneous nerve of forearm (posterior and anterior)
The median nerve passes down the arm and crosses the elbow. It then passes through the 2 heads of the pronator teres and gives off a nerve called what?
1 - anterior interosseus nerve
2 - radial nerve
3 - lateral cutaneous nerve
4 - brachialis nerve
1 - anterior interosseus nerve
- anterior as its on the front and interosseus as its on interosseus membrane
What is the most common fracture of the elbow, which can affect the anterior interosseus nerve, a branch of the median nerve?
1 - lateral epicondyle fracture
2 - medial epicondyle fracture
3 - supracondylar fracture
4 - radial groove fracture
3 - supracondylar fracture
The median nerve passes down the arm and crosses the elbow. It then passes through the 2 heads of the pronator teres and gives off anterior interosseus nerve (AIN). The AIN then innervates what muscles?
1 - deep flexors
2 - superficial flexors
3 - deep extensors
4 - superficial extensors
1 - deep flexor muscles
- flexor pollicis longus, flexor digitorum profundus, pronator quadratus, middle finger and index finger
The median nerve passes down the arm and crosses the elbow. It then passes through the 2 heads of the pronator teres and gives off anterior interosseus nerve (AIN). The median nerve will eventually pass through the carpal tunnel, but before it does it is sandwiched between which 2 muscles?
1 - flexor digitorum superficialis and flexor pollicis longus
2 - flexor digitorum profundus and flexor pollicis longus
3 - flexor digitorum superficialis and abductor pollicis longus
4 -flexor digitorum profundus and pronator quadratus
1 - flexor digitorum superficialis and flexor pollicis longus
The radial nerve, along with the deep brachial artery, travels down the spinal groove of the humerus and then passes from the anterior to the posterior compartment of the forearm, which is where all the extensors of the wrist and fingers are located. It is located deep to the brachioradialis and then as it crosses the elbow it has a branch that breaks off it that innervates all the extensors of the wrist and hand. What is this nerve called?
1 - anterior interosseus nerve
2 - radial nerve
3 - lateral cutaneous nerve
4 - posterior interosseus nerve
4 - posterior interosseus nerve (motor nerve only)
- posterior as it is located on posterior surface and interosseus as it is located along the interosseus membrane
Once the posterior interosseus nerve breaks off from the radial nerve just below the elbow, the radial nerve continues to the hand. What sensory information does the posterior interosseus nerve provide there?
1 - whole dorsal aspect of hand
2 - half of dorsal surface
3 - 1st dorsal web space as seen in the image
4 - digits 4 and 5
3 - 1st dorsal web space as seen in the image
The ulnar nerve loops around the medial epicondyle, which gives the common sensation we have when we bang the ‘funny bone’. It then passes deep to the 2 heads of which muscle?
1 - Flexor carpi ulnaris muscle
2 - Extensor carpi ulnaris muscle
3 - Flexor carpi radialis muscle
4 - Pronator teres muscle
1 - Flexor carpi ulnaris muscle
- then passes through the wrist through guyons canal
The median nerve can be compressed and cause symptoms. What are the 2 most common places this can be compressed?
1 - carpal tunnel and elbow
2 - carpal tunnel and shoulder
3 - carpal tunnel and forearm
4 - carpal tunnel and arm
2 - carpal tunnel and shoulder
- causing pronator syndrome
If a patient is presenting with loss of the thenar muscles only, which are innervated by the median nerve. Is this likely to be a distal or proximal compression?
- distal
- if it was proximal muscles in the forearm and arm would also be affected
If a patient is presenting with loss of the deep flexors of the forearm, the thenar muscles and inside of the palm sensory loss, which are innervated by the median nerve. Is this likely to be a distal or proximal compression?
- proximal
- but could be both
Patients who have carpal tunnel syndrome normally have normally senses on the skin as seen in the image below. Why is this?
1 - only motor function is affected in carpal tunnel
2 - sensory function is less affected by compression of carpal tunnel
3 - sensation supplied by palmer cutaneous branch of median nerve, which doesn’t pass through the carpal tunnel
4 - proximal damage spares sensory loss
3 - sensation supplied by palmer cutaneous branch of median nerve, which doesn’t pass through the carpal tunnel
- sensory of the skin is not supplied directly by median nerve
The hand of benediction is caused by damage to the median nerve, meaning the middle and index finger and thumb are not able to flex when you ask the patient to make a fist. Therefore what 2 muscles are affected by the damage to the median nerve?
1 - flexor digitorum superficialis and flexor pollicis longus
2 - flexor digitorum profundus and flexor pollicis longus
3 - flexor pollicis longus and flexor pollicis longus
4 - flexor carpi radialis and flexor pollicis longus
2 - flexor digitorum profundus and flexor pollicis longus
- loss of deep flexor muscles on radial side
The hand of benediction is caused by damage to the median nerve, meaning the thumb, middle and index finger are not able to flex due to loss of the deep flexor muscles on radial side (flexor digitorum profundus). Is this an active or passive test?
- active test
- only presents when you ask the patient to make a fist
The hand of benediction is caused by damage to the median nerve, meaning the middle and index finger and thumb are not able to flex due to loss of the deep flexor muscles on radial side. Specifically what muscles are affected to cause this sign that are all innervated by the median nerve?
- flexor pollicis brevis and longus
- flexor digitorum superficialis (flexes digits II-IV at MCT and IP joints)
- flexor digitorum profundus (flexes digits II and III at MCT and IP joints)
- lumbricals I and II (digits II and III) that flex MCT joints BUT extend IP joints
What is the most common fracture in children?
1 - medial epicondyle of humerus
2 - supracondyle of humerus (elbow)
3 - lateral condyle of humerus
4 - radial fracture
2 - supracondyle of humerus (elbow)
The most common fracture in children is the supracondyle of humerus (elbow). Once this has occurred patients are often unable to make the ok sign. Which nerve is generally damaged?
1 - radial nerve
2 - anterior interosseus nerve (branch of median nerve)
3 - ulnar nerve
4 - axillary nerve
2 - anterior interosseus nerve (branch of median nerve)
- lose of flexor pollicis longus (flexes the thumb)
- lose of flexor digitorum profundus (flexes digits II and III)
The most common fracture in children is the supracondyle of humerus (elbow). Once this has occurred patients are often unable to make the ok sign. The anterior interosseus nerve (branch of median nerve) is commonly damaged, meaning loss of or weakness in:
- flexor pollicis longus (flexes the thumb)
- flexor digitorum profundus (flexes digits II and III)
Is there any sensory loss?
- no
- anterior interosseus has no sensory stimulation
- sensory information from the hand comes from the palmer cutaneous branch of median nerve
There are ten components that run through the carpal tunnel, what are they?
- 4 flexor digitorum profundus tendons
- 4 flexor digitorum superficialis tendons
- flexor pollicis longus
- median nerve
To see if a patient has carpal tunnel syndrome we can perform some provocative testing. One of these is called Phalens test. What is this?
1 - patient touches dorsal (back of hands) sides of hands together
2 - patient touches palmer (front of hands) sides of hands together
3 - patient taps on flexor retinaculum
4 - patient extends the wrist and holds this position
1 - patient touches dorsal (back of hands) sides of hands together
- holds this for 1 minute which impinges the median nerve
- ask if and when symptoms present
To see if a patient has carpal tunnel syndrome we can perform some provocative testing. One of these is called Tinnels test. What is this?
1 - patient touches dorsal (back of hands) sides of hands together
2 - patient touches palmer (front of hands) sides of hands together
3 - patient taps on carpal tunnel location
4 - patient extends the wrist and holds this position
3 - tapping with finger or tendon hammer on carpal tunnel
- this irritates the nerve and symptoms can present
If we suspect someone has chronic carpal tunnel syndrome, what may we see in the hand?
- atrophy
- specifically the abductor pollicis brevis and opponens
If you were to break the humerus around the spiral groove, what nerve is at risk?
- radial nerve
- deep brachial artery is also at risk
What is the course of the radial nerve?
- leaves brachial plexus
- enters axilla travelling down humerus along spiral groove
- wraps laterally around humerus close to brachial artery
- passes anterior lateral epicondyle of the humerus
- passes through the cubital fossa
- runs along radius to hand
What are the main muscles of the arm that the radial nerve innervates?
- all three heads of the triceps
- extension of the elbow can be affected if there is a proximal radial nerve injury
The radial nerve innervates the extensors of the forearm and wrist. If a patient has a lesion of the radial nerve below the forearm, what key clinical sign can this cause?
1 - wrist drop
2 - lack of finger extension
3 - lack of finger flexion
4 - loss of sensation in the hand
1 - wrist drop
- radial nerve innervates the extensors of the wrist
The radial nerve innervates the extensors of the forearm and wrist. If a patient has a lesion of the radial nerve below the forearm this can present clinically as a wrist drop. What sensory aspects are also lost?
1 - lateral forearm in anterior posterior view
2 - lateral forearm and thumb
3 - lateral and medial forearm in anterior view
4 - whole forearm in anterior view
1 - lateral forearm in anterior posterior view
The radial nerve innervates the extensors of the forearm and wrist. If a patient has a lesion of the radial nerve below the forearm this can present clinically as a wrist drop. What 2 sensory aspects may be lost in the hand?
1 - first dorsal web space on palm
2 - thumb and digits II and III up to the DIP joint on the palmer surface
3 - thumb and digits II and III up to the DIP joint on the dorsal surface
4 - whole dorsal surface
1 - first dorsal web space on palm
3 - thumb and digits II and III up to the DIP joint on the dorsal surface
The radial nerve innervates the extensors of the forearm and wrist. If a patient has a lesion of the radial nerve below the forearm this can present clinically as a wrist drop. We can assess the extensor pollicis longus muscle as this is the best muscle to assess the radial nerve function. How is this test performed?
- patient puts hand flat on table
- try to raise thumb up and out
- movement is called retropulsion
At the elbow the radial nerve branches into 3 different branches. What are these branches?
1 - deep, medial and lateral branches
2 - medial, lateral and posterior branches
3 - posterior interosseus, deep and superficial branches
4 - posterior interosseus, lateral and superficial branches
3 - posterior interosseus, deep and superficial branches
At the elbow the radial nerve branches into 3 different branches, the posterior interosseus, deep and superficial branches. If the posterior interosseus branch is lost what happens at the wrist?
1 - sensory loss in hand and forearm
2 - sensory loss only in the hand
3 - wrist drop with no sensory loss
4 - wrist drop with sensory loss
3 - wrist drop with no sensory loss
- posterior interosseus branch is a motor nerve only
At the elbow the radial nerve branches into 3 different branches, the posterior interosseus, deep and superficial branches. Does the superficial radial branch provide motor, sensory information or both?
- sensory only
- innervates first dorsal webspace of the hand
What is the course of the ulnar nerve?
- down medial aspect of the arm with the brachial artery
- enters posterior compartment of the arm
- passes posteriorly to the elbow, hooking around the medial epicondyle of the elbow
- passes through the ulnar tunnel, supplying the elbow joint with articular branch
- enters forearm travelling deep alongside the ulna
The ulnar nerve travels down medial aspect of the arm with the brachial artery and enters the posterior compartment of the arm. It passes posteriorly to the elbow through the ulnar tunnel, supplying the elbow joint with articular branch, before entering the forearm travelling deep alongside the ulna. What is the most common place for ulnar nerve to be compressed?
1 - carpal tunnel
2 - guyons canal
3 - cubital tunnel
4 - axilla
3 - cubital tunnel
- posterior aspect of the elbow
What sensory input does the ulnar nerve provide in the hand?
1 - little finger and half of the ring finger
2 - digits III-V
3 - thumb and digits II and III
4 - little finger and digit IV
1 - little finger and half of the ring finger
What motor input does the ulnar nerve provide in the forearm?
1 - flexor carpi ulnaris + flexor carpi radialis
2 - flexor carpi radialis + flexor digitorum profundus
3 - flexor carpi ulnaris + ulnar 1/2 of flexor digitorum profundus
4 - flexor carpi ulnaris + flexor digitorum profundus
3 - flexor carpi ulnaris + ulnar 1/2 of flexor digitorum profundus
The ulnar nerve provides motor innervation for all intrinsic muscles of the hand except LOAF. What does the mnemonic LOAF stand for?
- L = Lateral two lumbricals.
- O = Opponens pollicis.
- A = Abductor pollicis brevis.
- F = Flexor pollicis brevis
- ALL INNERVATED BY MEDIAN NERVE
What is cubital tunnel syndrome?
- stretching or compression of the ulnar nerve
The ulnar nerve can be compressed at the elbow called cubital tunnel syndrome. Although not as common, it can also be compressed at the wrist through the canal it passes the wrist. What is the canal called?
1 - quadrangle space
2 - carpal tunnel
3 - triangular space
4 - guyons canal
4 - guyons canal
If the ulnar nerve is compressed or damaged, activation of the interossei muscles can be lost, meaning we are unable to do what with our fingers?
- abduct and adduct
- called Wartenberg’s sign
If the ulnar nerve is compressed or damaged, activation of the interossei muscles can be lost. This can cause ulnar claw. Which fingers will therefore be most affected in ulnar claw?
- ring and little fingers (IV and V)
- index and middle fingers (II and III) innervated by median nerve
To assess for ulnar nerve compression we can do a test called Froment’s sign. How is this test performed?
- patient holds a piece of paper between thumb and index finger
- you then try to pull the paper away from them
To assess for ulnar nerve compression we can do a test called Froment’s sign, which is where a patient holds a piece of paper between the thumb and index finger and you try to pull it away. Which muscle is this test assessing?
1 - adductor pollicis
2 - abductor pollicis
3 - opponens pollicis
4 - flexor pollicis longus
1 - adductor pollicis
- adding the thumb back to the hand plane
- abduction is moving the thumb out of the plane of the hand, like raising the thumb
Which nerve comes from the nerve roots of C5-C7 and does not go into the brachial plexus?
1 - serratus nerve
2 - long thoracic nerve
3 - pectoral nerve
4 - axillary nerve
2 - long thoracic nerve
The long thoracic nerve arises from the nerve roots of C5-C7 and does not go into the brachial plexus. Instead what does this muscle innervate?
1 - subscapularis
2 - serratus anterior muscle
3 - pectoralis major
4 - deltoid muscle
2 - serratus anterior muscle
The long thoracic nerve innervates the serratus anterior (SA). If the long thoracic nerve is damaged, what can this cause?
- SA keeps scapula onto the posterior chest wall
- if this is lost we can get scapula winging
- C5, 6 and 7 allow us to reach for heaven
In Erbs palsy, more commonly referred to as waiters tip (see image below), nerve roots C5 and C6 are affected. How does it affect the axillary nerve, which is innervated by C5 and C6?
- loss of deltoid and teres minor innervation
- unable to abduct or externally rotate the arm
- arm therefore sits close to body internally rotated
In Erbs palsy, more commonly referred to as waiters tip (see image below), nerve roots C5 and C6 are affected. How does it affect the musculocutaneous nerve, which is innervated by C5 and C6?
- loss of biceps and brachialis innervation
- unable to extend or supinate the elbow so arm remains straight and pronated
In Erbs palsy, more commonly referred to as waiters tip (see image below), nerve roots C5 and C6 are affected. There is 1 nerve that branches off the upper trunk of the brachial plexus that goes onto innervate the supra and infraspinatus. What is this nerve called?
1 - serratus nerve
2 - long thoracic nerve
3 - suprascapular nerve
4 - axillary nerve
3 - suprascapular nerve
In Erbs palsy, more commonly referred to as waiters tip (see image below), nerve roots C5 and C6 are affected. There is 1 nerve that branches off the upper trunk of the brachial plexus that goes onto innervate the supra and infraspinatus called the suprascapular nerve. How does Erbs palsy affect this nerve and what actions are affected?
- supraspinatus and infraspinatus innervation are lost
- unable to abduct and internally rotate arm
- arm sits close to midline and internally rotates
In Erbs palsy, more commonly referred to as waiters tip (see image below), nerve roots C5 and C6 are affected. The radial nerve can be affected in this condition. How is the radial nerve affected?
- brachioradialis and supinator innervation are lost
- unable to supinate and extend the wrist
- wrist remains in flexion
Plexopathy is when there is pathology to a nervous plexus. It can be very dangerous and has huge implications and there are a number of different names, depending on what is affected. Klumpke’s palsy is less common that Erbs palsy. In Klumpke’s palsy there is damage to C8 and T1. How does this present clinically in the forearm?
- ulnar nerve and some median nerve loss causing claw hand
- medial flexor or forearm and fingers lost
- wrist remains in extended position
Plexopathy is when there is pathology to a nervous plexus. It can be very dangerous and has huge implications and there are a number of different names, depending on what is affected. Klumpke’s palsy is less common that Erbs palsy. In Klumpke’s palsy there is damage to C8 and T1. How does this present clinically in the hand?
- ulnar nerve innervates most intrinsic muscles (except LOAF)
- MCPJ hyperextension IPJ flexion
Horners syndrome is a problem with sympathetic innervation to one side of the face. It presents with mitosis (constricted pupils) ptosis (droopy eyelid) and anhidrosis (inability to sweat). How can plexopathy to the brachial plexus cause horners syndrome?
- 2nd order neurons pass through brachial plexus
- 2nd order neurons pass into cervical ganglia
- if brachial plexus is damaged so to is the 2nd order neuron
Electromyography (EMG) is used to measures muscle response or electrical activity in response to a nerve’s stimulation of the muscle. What aspect of the muscle does EMG check to see if it is function correctly?
- motor unit
- includes motor neuron and all of the skeletal muscle fibres innervated by the neuron’s axon terminals, including the neuromuscular junctions between the neuron and the fibres
