A patient suffered from supracondylar fracture of humerus.On examination,on asking the patient to make a fist,the following picture is seen.This condition of the hand is due to which nerve injury?
A. Median Nerve
B. Ulnar Nerve
C. Radial Nerve
D. Axillary Nerve
Ans:A. Median Nerve.
The patient presents with Benediction Sign or Ponting index.
Median Nerve Injury
- Injury of median nerve at different levels causes different syndromes with varying motor and sensory deficits.
- Above the elbow
- Common mechanism of injury: A supracondylar humerus fracture
- Loss of pronation of forearm
- Weakness in flexion of the hand at the wrist
- Loss of flexion of radial half of digits and thumb
- Loss of opposition of thumb.
- Loss of abduction
- Pen touching test:The patient lies his hand flat on a table with his palm facing upwards.The patient is asked to abduct his thumb to touch the examiner’s pen which is held above it. This test is for the function of abductor pollicis brevis
- Loss of first 2 lumbricals.
- Thenar Atrophy
- Presence of an ape hand deformity when the hand is at rest, due to an hyperextension of index finger and thumb, and an adducted thumb.
- Presence of benediction sign or Pointing index when attempting to form a fist, due to loss of flexion of radial half of digits.
- Loss of sensation in lateral 3 1⁄2 digits including their nail beds, and the thenar area.
At the wrist
- Carpal Tunnel or laceration
- Presents without benediction hand and with normal wrist flexion,digital flexion and pronation.