Hand of benediction

The hand of benediction results from prolonged compression or injury of the median nerve or the ulnar nerve at the forearm or elbow.[1]

With median nerve compression, the "benediction" sign only appears when the patient attempts to make a fist, but is not present with the hand open.

With ulnar nerve compression, the "benediction" sign only appears when the patient attempts to extend all fingers, but is not present with the hand closed.

The term "hand of benediction" more frequently refers to damage of the median nerve, however.

Median nerve injury prevents the ability to flex the 2nd and 3rd digit metacarpophalangeal joint. This is due to the loss of innervation of the lateral 2 lumbricals of the hand and the lateral half of the flexor digitorum profundus. The extensor digitorum is left unopposed and the metacarpophalangeal joints of the 2nd and 3rd digits remain extended while attempting to make a fist.[2]

Ulnar nerve injury prevents the ability to extend the 4th and 5th digits by impairing the 3rd and 4th lumbricals, which results in the inability to extend the proximal and distal interphalangeal joints. [3]

The name arises from the invocation of a blessing used in Christian circles (see Benediction).

References

  1. ↑ http://stanfordmedicine25.stanford.edu/the25/hand.html
  2. ↑ http://stanfordmedicine25.stanford.edu/the25/hand.html
  3. ↑ http://stanfordmedicine25.stanford.edu/the25/hand.html
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