Joints
Elbow joint
Three joints in one capsule. The humero-ulnar part governs flexion and extension, the radio-ulnar part pronation and supination; the arm can therefore bend and turn at the same time.
- Joint type
- Compound joint: humero-ulnar (hinge, ginglymus), humeroradial (restricted ball and socket) and proximal radio-ulnar (pivot)
- Body region
- Elbow
- Latin name
- Articulatio cubiti
Movements, axes and normal values
| Movement | Plane | Axis | Normal range | End feel |
|---|---|---|---|---|
| Flexion | sagittal | transverse through the trochlea | 0-150 degrees | soft (soft tissue) |
| Extension | sagittal | transverse through the trochlea | 0 degrees; up to 10 degrees of hyperextension is normal | hard (olecranon in the olecranon fossa) |
| Supination | transverse | longitudinal through the radial and ulnar heads | 0-90 degrees | elastic |
| Pronation | transverse | longitudinal through the radial and ulnar heads | 0-85 degrees | elastic to hard |
- Close-packed position
- Humero-ulnar: full extension with supination. Humeroradial: 90 degrees of flexion with 5 degrees of supination.
- Resting (loose-packed) position
- 70 degrees of flexion, 10 degrees of supination
- Capsular pattern
- Flexion more limited than extension, while pronation and supination stay free unless the joint is severely affected.
- Arthrokinematics
- The concave trochlear notch of the ulna moves over the convex trochlea: roll and glide go the same way. During flexion the ulna rolls and glides forward. The radial head turns on its own axis inside the anular ligament during pronation.
- Stability
- Bony congruence of the trochlea (the main stabiliser), the ulnar collateral ligament against valgus, and the radial collateral ligament with the anular ligament against varus and against the radial head slipping away.
- Palpation
- Lateral and medial epicondyle, olecranon (the three form an isosceles triangle at 90 degrees of flexion), radial head about 2 cm distal to the lateral epicondyle, palpably turning during pronation and supination.
- Clinical
- Lateral epicondylitis (tennis elbow) and medial epicondylitis (golfer's elbow); cubital tunnel syndrome with compression of the ulnar nerve behind the medial epicondyle; olecranon bursitis; in children pulled elbow, where the radial head slips out of the anular ligament.
- Source
- Kapandji, Physiologie articulaire deel 1; Magee, Orthopedic Physical Assessment