Elbow joint
The elbow joint is a complex joint combining three articulations in one joint capsule. It provides flexion-extension of the forearm and rotation (pronation-supination) - movements necessary for everyday activities from eating to typing.
Three joints
| Joint | Bones | Movement |
|---|---|---|
| Humeroulnar | Shoulder block + ulnar trochlear notch | Flexion/extension |
| Brachioradialis | Capitate humerus + radial head | Flexion/extension |
| Proximal radioulnar | Radial head + ulnar radial notch | Pronation/supination |
The amplitude of flexion-extension is 0–145°, pronation-supination - 90° in each direction.
Bony landmarks
- Olecranon (olecranon) - the posterior protrusion that we feel as an “elbow”
- Medial epicondyle - insertion of flexor muscles and “funny bone” (passes through the ulnar nerve)
- Lateral epicondyle - place of attachment of extensor muscles
Bundles
- Medial (ulnar) collateral - the main stabilizer for valgus loading (important for throwing movements)
- Lateral collateral – prevents varus deformity
- Annular ligament - wraps around the head of the radius, holding it in the notch, but allowing it to rotate
Nerves
The three most important nerves of the arm pass through the elbow area:
- Ulnar nerve - in the groove behind the medial epicondyle (the blow causes an “electric” lumbago)
- Median nerve - in the anterior fossa of the elbow
- Radial nerve - at the lateral epicondyle
Clinical significance
- Lateral epicondylitis (“tennis elbow”) - inflammation at the insertion site of the extensor muscles. It occurs not only among tennis players, but also when working at a computer.
- Medial epicondylitis (“golfer’s elbow”) is an inflammation of the flexor muscles.
- Dislocation of the elbow joint is the second most common dislocation after the shoulder.
- Radial head fracture is the most common fracture in the elbow area in adults.
The anatomy of the elbow joint is complex, and accurate diagnosis of injuries requires knowledge of the relationships of the three joints, ligaments, and nerves.
Do you want to see all three joints of the elbow joint in volume? In 3D atlas Humio, detailed interactive models are available that can be disassembled layer by layer.