Shortening of the fourth/fifth metacarpals/metatarsals
Shortening of the fourth/fifth metacarpals and less commonly metatarsals is seen in a variety of apparently disparate conditions.
Common causes 2:
- post-infective (e.g. osteomyelitis, yaws, tuberculosis dactylitis)
- post-traumatic (acute or chronic/healed and particularly those involving growth plate)
- Turner syndrome
Uncommon causes 2:
- basal cell naevus syndrome (Gorlin syndrome)
- hereditary multiple exostosis syndrome 5
- juvenile idiopathic arthritis
- sickle cell disease with secondary infarction
- Langer-Giedion syndrome
Isolated shortening of the 5th metacarpals has been recently described in a familial variant of type 1 diabetes mellitus 3.
Hand x-rays readily identify the abnormality and can be assessed by drawing a line along the heads of the 4th and 5th metacarpals. If this line intersects the head of the 3rd metacarpal then shortening is deemed to be present.
Thus, shortened 4th metacarpal is the key to this finding. It is known as the metacarpal sign. It is important to note that a positive sign can be seen in up to 10% of normal individuals 4.
- 1. Primer of diagnostic imaging. Ralph Weissleder, Jack Wittenberg, Mukesh G. Harisinghani. St. Louis : Mosby, c2003. ISBN:0323023282 (find it at amazon.com)
- 2. Reeder and Felson's gamuts in radiology. Maurice M. Reeder; with MRI gamuts by William G. Bradley, Jr., and ultrasound gamuts by Christopher R. Merritt and input from a distinguished 20-member subspecialty editorial board. New York : Springer, c2003. ISBN:0387955887 (find it at amazon.com)
- 3. Patel VK, Davies HA. Insulin resistance Type A and short 5th metacarpals. Diabet. Med. 2003;20 (6): 500-4. [pubmed citation]
- 4. An evaluation of the metacarpal sign (short fourth metacarpal). Pediatrics. 1970;46 (3): 468-71. Pediatrics (abstract) [pubmed citation]
- 5. Tzaveas A, Paraskevas G, Gekas C et-al. Anatomical variation of co-existence of 4th and 5th short metacarpal bones, sesamoid ossicles and exostoses of ulna and radius in the same hand: a case report. 2008;1 (1): 281. doi:10.1186/1757-1626-1-281 [free text at pubmed] [pubmed citation]
- 6. Castriota-Scanderbeg A, Dallapiccola B. Abnormal Skeletal Phenotypes. Springer. (2006) ISBN:3540303618. Read it at Google Books - Find it at Amazon