Ulna Unlabeled, With the Radius

The two forearm bones from the front: 16 landmarks, labeled or blank.

Ulna Unlabeled, With the Radius

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Tap the ulna

1 of 7

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Write the name of each numbered part.Answer key

  1. Olecranon process
  2. Trochlear notch
  3. Coronoid process
  4. Radial notch
  5. Ulnar tuberosity
  6. Ulna
  7. Head of ulna
  8. Styloid process of ulna
  9. Head of radius
  10. Neck of radius
  11. Radial tuberosity
  12. Radius
  13. Distal end of radius
  14. Ulnar notch
  15. Styloid process of radius
  16. Interosseous membrane

Drawn for this site on 2026-10-05 by script. Licence: own drawing; outlines after a public domain plate.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: 35 bones of the whole body, front and back

All 16 parts on the diagram

Show the list

Start here: 7 main parts 7

  1. Olecranon process The upper back part of the ulna. It forms the bony tip of the elbow.
  2. Trochlear notch Joins the trochlea of the humerus at the elbow. A large C-shaped notch.
  3. Ulna The medial bone of the forearm, on the little-finger side.
  4. Head of radius The disc-shaped top of the radius. It meets the capitulum of the humerus and turns in the radial notch of the ulna.
  5. Radius The lateral bone of the forearm, on the thumb side. Its shaft is slightly curved.
  6. Styloid process of radius A pointed projection on the outer lower radius for wrist ligaments. It reaches lower than the ulna's styloid process.
  7. Interosseous membrane A sheet of dense connective tissue. It joins the radius and ulna along their shafts.

The ulna and the membrane: 9 5

  1. Coronoid process A prominent lip of bone. It forms the lower margin of the trochlear notch.
  2. Radial notch A small smooth area on the side of the ulna. The head of the radius sits here, forming the proximal radioulnar joint.
  3. Ulnar tuberosity A roughened area on the front of the ulna. It lies just below the coronoid process.
  4. Head of ulna The small rounded distal end of the ulna.
  5. Styloid process of ulna A short bony projection from the head of the ulna. It anchors tissue joining the two bones' lower ends.

The radius: 7 4

  1. Neck of radius The narrowed region just below the head of the radius.
  2. Radial tuberosity An oval bony bump below the neck on the inner side. It serves as a muscle attachment.
  3. Distal end of radius The broad lower end. Its smooth surface meets two carpal bones at the wrist joint.
  4. Ulnar notch A shallow hollow on the inner side of the lower radius. It meets the head of the ulna in the distal radioulnar joint.

How this list was compiled: Read 2026-09-26. OpenStax Anatomy and Physiology 2e, section 8.2 Bones of the Upper Limb, https://openstax.org/books/anatomy-and-physiology-2e/pages/8-2-bones-of-the-upper-limb : the ulna as the medial and the radius as the lateral (thumb side) forearm bone, joined by the interosseous membrane of dense connective tissue; the ulna's C-shaped trochlear notch joining the trochlea of the humerus, the coronoid process forming its lower margin, the ulnar tuberosity below, the radial notch forming the proximal radioulnar joint, the olecranon forming the tip of the elbow, the shaft, the head of the ulna and its styloid process; the radius's disc-shaped head meeting the capitulum and the radial notch, the neck, the radial tuberosity as a muscle attachment, the slightly curved shaft, the distal end meeting two carpal bones, the ulnar notch forming the distal radioulnar joint, and the styloid process of the radius projecting more distally than the ulna's. Licence: own work

The drawing: Drawn for this site on 2026-10-05 by script. The outlines of the two bones were read off a public domain plate, Henry Vandyke Carter's drawing in Henry Gray, Anatomy of the Human Body (20th US edition, 1918), fig. 213, 'Bones of left forearm. Anterior aspect' (https://commons.wikimedia.org/wiki/File:Gray213.png), mirrored to show a right forearm, with the radius brought to the ulna and the shafts drawn a little slimmer where they face each other. The inner lines, tints, hatching and the membrane are our own, placed by eye against the same plate. Licence: own drawing; outlines after a public domain plate

How it works

The ulna unlabeled, with the radius beside it: both forearm bones from the front, elbow at the top, and the membrane that joins them. Start with the 7 main parts, then every landmark of each bone.

Read the full guide

Which bone is which

The radius is on the thumb side and the ulna on the little-finger side. At the elbow the ulna is the big one, with the olecranon and the trochlear notch; at the wrist the radius is the big one.

Where the two bones meet

The head of the radius turns in the radial notch of the ulna at the elbow, and the head of the ulna sits in the ulnar notch of the radius at the wrist. The interosseous membrane joins their shafts.

  • Each notch is named for the bone that fits into it: the radius fits the radial notch, the ulna the ulnar notch.

Questions and answers

Which is lateral, the radius or the ulna?

The radius is lateral, on the thumb side of the forearm. The ulna is medial, on the little-finger side.

What is the olecranon?

The upper back part of the ulna, which forms the bony point of the elbow.

What does the unlabeled radius and ulna diagram show?

The same two bones with 16 numbered rings and no names, ready to label by hand.

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