From the case:
Negative metacarpal sign
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This is a radiograph of a normal hand and the metacarpal sign is absent. In other words, a line drawn along the heads of the 4th and 5th metacarpals does not intersect the head of the 3rd metacarpal. This is normal. If shortening of the 4th metacarpal is present then the line will intersect the head of the 3rd metacarpal.
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