ulna
Pronunciation: /ˈʌlnə/
noun ( plural ulnae /-niː/ or ulnas)
- the thinner and longer of the two bones in the human forearm, on the side opposite to the thumb. Compare with radius (sense 2 of the noun).
- the bone in a quadruped’s foreleg or a bird’s wing that corresponds to the ulna in a human being.

Origin:
late Middle English (denoting the humerus): from Latin; related to ell1