- The ulna is a long, thin bone in your forearm, on the opposite side of your arm from your thumb.
An example of ulna is a bone in your forearm.
nounpl. ul·nas or ul·nae
- The bone extending from the elbow to the wrist on the side opposite to the thumb in humans.
- A corresponding bone in the forelimb of other vertebrates.
Origin of ulnaLatin, elbow, forearm; see el- in Indo-European roots.
(plural ulnae or ulnas)
From Latin ulna (â€œelbowâ€).