overview of upper limb Flashcards
what allows the upper limb to move
shoulder, large range of movement, wide area
what do the muscles of the shoulder do for the upper limb
allow it to move and can anchor it to trunk
where do the muscles that move the fingers originate?
intrinsic muscles in the hand for fine fine movement
extrinsic in forearm for power
What are the two main types of grip
power grips and precision grips
which grips are most primitive?
power grips and present in new born babies
What do hypothenar muscles do in power grips
stabilise medial side of palm against handle
What do wrist extensors do in power grips
provide a stable base
What types of grips are examples of power grips
cylindrical, spherical, hook, lateral prehension
What muscles are used in precision grips
intrinsic muscles cooperate with long flexor and extensor muscles (extrinsic) to give a more complex movement holding objecting between tip of thumb and finger(s)
When will precision grip develop?
9 months of age
what types of grips are precision?
plate pinch key or pincer
what are the subgroups of power grips and what is the difference between them
prehensile where thumb is involved or non prehensile where thumb isn’t involved
what is an example of a non prehensile grip
hook
What will cause damage to the radial nerve
fracture to mid shaft of humerus
What groove does the radial groove run in
spiral groove, or radial groove
what is the main symptom of radial nerve injury and why
wrist drop as no extension of wrist and digits as no action of FDS and FDP
what is Saturday night palsy caused by
radial nerve in armpit or upper arm compressed or stretched due to falling asleep with arm hanging
what happens after radial nerve injury
nerves will regrow and repair
what is the only area which is purely radial nerve
thumb and first finger web of skin so if damaged get loss of sensory feeling here
What is the cause of radial nerve palsy in newborns and symptoms
prolonged pressure of inferior arm through labour stretching nerve in armpit
wrist drop
unable to extend thumb and MCP of all digits
weak elbow extension
Where is the median nerve at risk of damage
as it comes into cubital fossa - supra condular humerus fracture, oeverything below loses innervation
what happens when you ask a high median nerve injury patient to make a fist
hand of benediction
index and middle won’t flex and thumb doesn’t move
4th and 5th DIP can flex as ulnar nerve inner area medial FDP and FCU
what is low median nerve injury example
carpal tunnel syndrome
reduces size of carpal tunnel can compress median nerve
progressive loss of coordination and strength in thumb
if you ask a low median nerve injury patient to close their fist what happens
they can weakly close fingers and thumb as FPL works but thenar muscles to thumb are not working as not innervated
Where is the most likely place where the ulnar nerve will be injured?
medial epicondyle if humerus
What does ulnar nerve lead to? symptoms?
clawhand
Why is there an ulnar paradox
in high nerve injury, clawing of the hand looks more subtle whereas high nerve injury indicates worse muscle damage
What is the difference between high and low ulnar nerve palsy?
high - all muscles lost and get cubital tunnel syndrome
low - FDP pulls digits 4 and 5 into flexion, Guyon’s canal syndrome
