VCU Department of Radiology

When a line is drawn along  the heads of the 4^th and 5^th metacarpals, it should not intersect the  3^rd metacarpal.  If it does the 4^th metacarpal is shortened.

These bones can be shortened in a number of conditions, the most common of which is idiopathic as in this case.

Up to 9.6% of the population has this finding.

Shortened 4^th and 5^th metacarpals also occur in a number of conditions such as post-traumatic/post-infectious, Turner syndrome, pseudohypoparathyroidism, pseudopseudo- hypoparathyroidism, Basal cel nevus(Gorlin) syndrome, Sickle cell disease with infarction, Hereditary multiple exostosis and homocystinuria.