interesting. radial nerve palsy
Why will a patient with wrist-drop resulting from radial nerve injury be unable to perform a power grip?
If the extensor muscles are paralyzed by a radial nerve injury, a power grip becomes impossible because the wrist flexes as well as the fingers, so the fingers are pulled open by the relative shortness of the extensors. (Try gripping with your wrist fully flexed.) Also, muscle fibers can only contract by a fixed percentage of the resting length. An extended wrist is required to allow sufficient shortening force to be supplied to the fingers.
Proper treatment for this patient might include changing his type of crutch and beginning physiotherapy.
If the extensor muscles are paralyzed by a radial nerve injury, a power grip becomes impossible because the wrist flexes as well as the fingers, so the fingers are pulled open by the relative shortness of the extensors. (Try gripping with your wrist fully flexed.) Also, muscle fibers can only contract by a fixed percentage of the resting length. An extended wrist is required to allow sufficient shortening force to be supplied to the fingers.
Proper treatment for this patient might include changing his type of crutch and beginning physiotherapy.
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