The hand of benediction, also known as benediction sign or preacher's hand, occurs as a result of prolonged compression or injury of the median nerve at the forearm or elbow.
The term "hand of benediction" refers to damage of the median nerve. However, the name is misleading as the patients with this median nerve problem usually can flex all fingers except for the index finger. The index finger is still extended at the metacarpophalangeal joint (MCP joint) when the ulnar nerve innervated muscles (the interossei muscles) are still working. The index finger is not flexed at the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints, which looks like a pointing finger. Pointing Finger is therefore a much better term to recognize this condition.
The middle finger is flexed because of the connection between the flexor digitorum profundus (FDP) tendons, which is called the Quadriga phenomena.
Video Hand of benediction
References
Source of article : Wikipedia