Which finding would demonstrate rotational misalignment in a patient with a fourth metacarpal fracture?

• A. Base of the ring fingernail and index fingernail line up in the partially closed hand
• B. Fingernails of the open hand form an asymmetric arc
• C. Ring finger of the closed hand overlaps the little finger
• D. Ring finger of the open hand is shortened

Answer: (C)

Rotational misalignment shows up when the hand is made into a fist. If a metacarpal bone is rotated after a fracture, the affected finger wont line up with its neighbors and may cross over or overlap another finger. For a fourth metacarpal fracture, the hallmark is the ring finger rotating enough that, when you clench your fist, it overlaps the little finger. That crossing-over you can visually see on the palmar side of the hand is the best clue that rotation has occurred.

The other signs aren’t as specific for rotation: alignment of the nails in a partially closed hand suggests little to no rotational deformity; an asymmetric arc of the nails with an open hand isn’t the standard sign of rotation; and shortening of the ring finger indicates fracture with possible bone shortening, but doesn’t by itself demonstrate rotational misalignment.