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The interactive dog atlas · Skeleton · Forelimb

Ulna ulna

The ulna is the rear bone of the forearm, alongside the radius. Its upper end, the olecranon, is the bump we call the point of the elbow.

Open in the interactive atlas Guide: Skeleton Worksheet

Educational material, not a diagnostic tool. Written by the Mantrailing România team from veterinary sources we read. Updated 14.11.2026.

Dog in left lateral view — exterior, muscles, skeleton and organs Vector study after the Ellenberger, Baum and Dittrich plates: a standing dog, head to the left, deep chest and digitigrade limbs. The four layers use the same contour: exterior with body regions, superficial muscles, skeleton and organs.
  1. Ulna
  2. Radius
  3. Humerus
  4. Carpal bones
Ulna on the atlas drawing, "Skeleton" layer, with the neighbouring structures. Left lateral view, after the Ellenberger, Baum and Dittrich plates.

Where it is

The rear bone of the forearm; its upper end is the point of the elbow.

System
Forelimb
Region
Forelimb

What it is and what it does

The ulna is the second bone of the forearm. It sits behind the radius at the elbow and on the outer side at the carpus. Its upper end, the olecranon, is the bump we call the point of the elbow; the tendon of the triceps muscle, the one that extends the elbow at every stride, attaches to it.

Some sources wrongly state that the biceps attaches to the olecranon; the muscle that inserts on the olecranon is the triceps brachii.

Worth remembering

The tendon of the triceps, the muscle that extends the elbow at every stride, attaches to the olecranon.

Names

  • Also called: cubitus.
  • Latin term: ulna.
  • In Romanian: Ulna (Romanian page).

Guides it appears in

From the same region: Forelimb

All structures, in the atlas · Flashcards: skeleton