Upper Limb Compression Neuropathies Flashcards
Recall the UL dermatomes and myotomes of the brachial plexus
+ Indicate which are covered by each of the 3 main nerves of the UL
C8 is both finger flexion and Finger Adduction
A supracondylar fracture is most likely to injure which UL nerve?
Anterior interosseus nerve
2nd to it is radial
But it poses a threat to all of the nerves
What is the sensory innervation of the median nerve?
Palmar 3 and 1/2 digits
+ lateral 2/3 of palmar surface (including thenar eminence)
If a patient has normal sensation of the Palmar 3 and 1/2 digits but not of the thenar eminence what nerve is involved?
Palmar cutaneous branch of the median nerve
What hand muscles are innervated by the median nerve? Name them and for each, state the movement
LOAF muscles
Lateral 2 lumbricals (flexion of MCP and extension of PIP for index and middle finger)
Opponens Pollicis Brevis: Opposition of thumb
Abductur pollicis brevis: Abduction of thumb
Flexor pollicis brevis: Flexion of thumb
For the Median nerve, indicate the
Fractures most associated with its injury
Motor innervation (including muscles + function)
Sensory innervation
Define carpal tunnel syndrome
Compression neuropathy of the median nerve as it passes through the carpal tunnel
Give the causes/RF for Carpal tunnel
What are the boundaries of the carpal tunnel?
You can replace the roof with flexor retinaculum
What are the contents of the carpal tunnel?
What is the typical presentation of carpal tunnel?
Pain and paraesthesia along the distribution of the median nerve worse at night and relieved by shaking hands
What are the 3 special tests for carpal tunnel syndrome?
You walk into an osce station and are asked to perform a hand examination on a patient complaining of paraesthesia on the palm of her hand worse at night. What must you assess specifically for this condition?
Do not forget to offer Grip strength!!
How is grip strength assessed?
How is it performed?
Dynamometer
patient should be
seated upright
forearm in a neutral position
Wrist extended at 15-30 degrees
Best of 3 measurements
Carpal tunnel syndrome is typically diagnosed clinically. What is the main diagnostic investigation for this and what findings would you expect?
NCS is now used as the gold standard. It looks for 3 things:
1) Reduced amplitude of APs
2) Reduced conduction velocity through area of compression
3) Increadsed distal latency
give the management of carpal tunnel along with its escalations
What is shown in this image?
Scar post-carpal tunnel release?
What is being “released” is carpal tunnel release surgery?
Flexor retinaculum
What is Pillar pain?
Incomplete resolution of symptoms due to “Double Crush” phenomenon whereby the nerve is actually compressed at 2 or more sites (so the release only solved one of the many different points of compression)
What are the complications of Carpal tunnel release?
For the Anterior Interosseous nerve,
What nerve is it a branch of?
indicate the
Fractures most associated with its injury
Motor innervation
Sensory innervation
Branch of the median nerve
For the Radial nerve, indicate the
Fractures most associated with its injury
Motor innervation
Sensory innervation
Very low yield:
What syndromes are caused by radial nerve injury
Most important thing is to use it as differentials for radial nerve injury
What is the management of A radial nerve injury?
Like any of the other compression neuropathies
For the Ulnar nerve, indicate the
Fractures most associated with its injury
Motor innervation
Sensory innervation
Can Tinel’s test be performed for ulnar nerve compression neuropathy?
What about radial?
Radial is too deep but ulnar can be done over the course of it. Best place is to go to olecranon
Explain the Ulnar paradox
What 2 syndromes may arise from ulnar nerve compression neuropathy?
Although diagnosed clinically, what investigation is best performed to confirm the diagnosis of ulnar nerve compression neuropathy?
Nerve conduction studies looking for delayed conduction and reduced action potential
How would you manage an ulnar nerve compression neuropathy?
Like any of the others
Give the causes of Carpal Tunnel Syndrome
MEDIAN TRAP
Myxoedema
Ethanol (alcohol)
Diabetes
Iatrogenic
Amyloidosis
Neoplasm (gangliomas, osteophytes, lipoma)
Trauma
Rheumatoid arthritis (osterophytes)
Acromegaly
Pregnancy
Congenital: Remnant of Median artery) + Large FDS Belly
What is saturday night palsy?
What nerve is it associated with?
Saturday night palsy is compression of the radial nerve against the humerus when arm hung
What is the most common mechanism of injury for the following nerves:
Median:
Ulnar:
Radial: (2)
Median: Carpal Tunnel Syndrome
Ulnar: Elbow Trauma
Radial: Humeral shaft fracture Saturday night palsy
