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beginnerSource-checked11 min read

The Elbow: An Overview

Three joints in one capsule — bending/straightening and forearm rotation, stabilized by strong ligaments.

Before this: The Arms: An Overview

You will be able to

  • Describe the three joints that make up the elbow region.
  • Explain the difference between the humeroulnar joint (bending) and the proximal radioulnar joint (rotating).
  • Name the elbow's key stabilizing ligaments at a basic level.
Simplified front view of a bent elbow showing the humerus above, and the radius and ulna forming the forearm below, meeting at the elbow joint with the lateral and medial epicondyles marked on the humerus.
Elbow — humerus, radius, and ulna (simplified). A beginner-level schematic of the elbow's bony structure, including the medial and lateral epicondyles.
Illustration: Anatomy Learning Platform (original) · CC0-1.0 (public domain dedication)

⚠ Safety note

Inability to bend or straighten the elbow after an injury, visible deformity, or numbness/tingling into the hand needs prompt medical evaluation. A trainer coaches safe elbow loading; they do not diagnose ligament or nerve injuries.

Three joints, one capsule

What we casually call 'the elbow' is really three joints sharing one joint capsule:

  • The humeroulnar joint — a hinge between the humerus and ulna that bends and straightens the elbow.
  • The humeroradial joint — a related gliding surface between the humerus and radius.
  • The proximal radioulnar joint — where the radius rotates against the ulna, letting the forearm

pronate (palm down) and supinate (palm up) without needing to move the elbow itself.

Held together by ligaments

Strong collateral ligaments on the inner (ulnar) and outer (radial) sides of the elbow resist excess side-to-side stress, particularly important during throwing and heavy pressing movements.

The bony bumps that cause elbow pain

The bony bumps on either side of the elbow (epicondyles) are where the wrist muscles begin. This is why wrist-tendon overuse problems — from gripping, typing, or racquet sports — are often felt as pain right at the elbow rather than in the forearm itself.

Sources for this lesson

“The elbow region comprises the humeroulnar, humeroradial, and proximal radioulnar joints within a shared capsule.”

Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 9.5 Synovial Joints

Peer-reviewed textbook · License: CC BY-NC-SA 4.0 · Last checked 2026-07-19

Take the quiz (3 questions)Explore the Elbows

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