The bone extending from the elbow to the wrist on the side opposite to the thumb in humans. (noun)
A corresponding bone in the forelimb of other vertebrates. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "ulna" in a sentence
"Plaque-clogged arteries in the abdomen suggest a red-meat eater; black-encrusted lungs signify long-term nicotine addiction; the faint indentation in the ulna is the scarred evidence of an arm broken in childhood."
"For four or five days I thought over the history of his injury and the resulting inability to rotate the radius around the ulna -- in other words, to turn his hand over."
"At the elbow, which is the first angle of the wing, reaching backward when the wing is folded, the humerus articulates in a wisely designed way with two other bones, called the ulna and radius, which together constitute the forearm and extend to the wrist joint."