S Rajkumar, S Tay
function, nerves of hand, single test
S Rajkumar, S Tay. A Single Clinical Sign To Test For Functioning Of All 3 Nerves Of The Hand. The Internet Journal of Orthopedic Surgery. 2005 Volume 3 Number 1.
There are various signs and tests used in routine practice when examining nerve function of the hand. There are specific tests for detecting nerve weakness
3 Nerve test - (Kumar Test)
Ask the patient to dorsiflex his/her wrist,
Abduct the fingers of 3 rd , 4th and 5 th fingers and
Make a ring (O) sign with thumb and index finger tips touching each other (Figure 1). This single test will assess motor power of all three nerves.
Inability to dorsiflex wrist indicates Radial nerve weakness (wrist dorsiflexors 1 ); inability to abduct the ulnar half of fingers indicates Ulnar nerve weakness (Dorsal Interossei 1 ) and inability to appose thumb and index finger tips to make an O sign indicates Median nerve weakness (Flexor Pollicus Longus and Flexor Digitorium Profundus of index finger 1 ).
This test can be effectively performed in a clinical setting to rapidly test for nerve weakness although the sensory component cannot be assessed at the same time. If a nerve weakness is detected, then further tests can be carried out to confirm it.
This test is a useful test to rapidly diagnose nerve injuries in casualty and clinical setting.