Hand of benediction

The hand of benediction results from prolonged compression or injury of the median nerve at the level of the elbow or upper arm.^[1]

The ability to flex the digits 2–3 at the metacarpophalangeal joints is lost as is the ability to flex and extend the proximal and distal interphalangeal joints. 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 which are supplied by the median nerve. Flexion at the proximal interphalangeal joints of digits 4–5 is weakened, but flexion at the metocarpophalangeal joints and distal interphalangeal joints remains intact. The extensor digitorum is left unopposed and the metacarpophalangeal joints of digits 2–3 remain extended while attempting to make a fist.^[2]

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

Distinction from Ulnar Claw

Some sources^[3] use the term "hand of benediction" to include both the condition described above and ulnar clawing, which is a common source of confusion. Both signs have similar presentations, but the term "hand of benediction" more frequently refers only to damage to the median nerve and is seen with attempted flexion of all the digits (leaving the 2nd and 3rd digits extended), while "ulnar claw" refers exclusively to damage to the ulnar nerve and is seen with attempted extension of all the digits (leaving the 4th and 5th digits flexed).

References

1. http://teachmeanatomy.info/the-median-nerve/
2. "Netter Image". Netterimages.com. Retrieved 2011-09-02.
3. "Taber's Medical Dictionary:benediction hand". Tabers.com. 2009-06-23. Retrieved 2011-09-02.