cap·i·tel·lum 
(kăp′ĭ-tĕləm)
(kăp′ĭ-tĕləm)n. pl. cap·i·tel·la (-tĕlə)
Anatomy
Anatomy
The rounded protuberance at the lower end of the humerus that articulates with the radius.
[Late Latin, diminutive of Latin caput, capit-, head; see kaput- in the Appendix of Indo-European roots.]