ulna

American  

[uhl-nuh] / ˈʌl nə /

noun

ulnae, plural ulnas plural

1. Anatomy. the bone of the forearm on the side opposite to the thumb.

2. a corresponding bone in the forelimb of other vertebrates.

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ulna British  

/ ˈʌlnə /

noun

1. the inner and longer of the two bones of the human forearm

2. the corresponding bone in other vertebrates

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Other Word Forms

Derived Forms

• postulnar
  adjective
• ulnar
  adjective

Inflected Forms

noun

• ulnae
  plural
• ulnas
  plural

Etymology

Origin of ulna

1835–45; < Latin: elbow; akin to Greek ōlénē, Old English eln ell ²

Explanation

Your ulna is a bone in your arm — it sits in the forearm beside the radius bone, connecting your pinky finger to your elbow. The ulna is longer than the radius, and you need it for things like turning a car's steering wheel and throwing a ball. Because the ulna extends to the very tip of the elbow, it's sometimes called the "elbow bone," and in fact ulna means "elbow" in Latin. Most animals have an ulna, although it's often at least partially fused to the radius.