Fourth metacarpal bone

The base is small and quadrilateral; its superior surface presents two facets, a large one medially for articulation with the hamate, and a small one laterally for the capitate.

On the radial side are two oval facets, for articulation with the third metacarpal; and on the ulnar side a single concave facet, for the fifth metacarpal.

Clinical relevance

A shortened fourth metacarpal bone can be a symptom of Kallmann syndrome, a genetic condition which results in the failure to commence or the non-completion of puberty. A short fourth metacarpal bone can also be found in Turner syndrome, a disorder involving sex chromosomes.

A fracture of the fourth and/or fifth metacarpal bones transverse neck secondary due to axial loading is known as a boxer's fracture.