From Longman Dictionary of Contemporary Englishulnaul‧na /ˈʌlnə/ noun (plural ulnae /-niː/) [countable] medicalHBH the inner bone of your lower arm, on the side opposite to your thumb
Examples from the Corpus
ulna• Right arm, compound spiral fractures or radius and ulna.• Also in a remarkable state of preservation is a flute made h-am the ulna at Vulture.• A shinbone was broken, twisted - as was the ulna in one arm, and several ribs.Origin ulna (1500-1600) Modern Latin Latin, “elbow” 