Yes, the radial head articulates with the capitellum of the humerus.
This is a fundamental anatomical relationship of the elbow joint, forming the radiocapitellar joint, which is one of the three articulations within the elbow complex (along with the ulnohumeral and proximal radioulnar joints).
Anatomical Details
The radiocapitellar articulation is a critical component of elbow biomechanics:
- The radial head's convex peripheral cartilaginous rim articulates with the concave surface of the capitellum 1
- The radius of curvature of the radial head matches remarkably well with the capitellum—studies show 94% of patients have less than 1mm difference between these two surfaces, with 63% within 0.5mm 1
- The radial head height is approximately 78% of the capitellar articular width 1
Clinical Significance
This articulation is clinically relevant in multiple contexts:
Fracture patterns: Radial head fractures are the most common elbow fractures in adults, accounting for 50% of cases 2. These fractures frequently occur in association with:
- Posterior elbow dislocations
- Terrible triad injuries (radial head fracture + coronoid fracture + posterior dislocation) 2, 3
- Capitellum fractures 3
Biomechanical considerations: The radiocapitellar joint experiences significant forces during throwing motions. Research demonstrates that during rapid elbow extension (as in baseball pitching), the radial head can lag behind ulnohumeral motion by up to 4mm, potentially causing edge loading and elevated shear forces on the capitellum 4. This asynchronous motion may explain osteochondritis dissecans lesions in throwing athletes.
Prosthetic implications: When radial head replacement is necessary, prosthetic design must account for this articulation. Non-anatomical circular prostheses show reduced contact areas and elevated contact pressures compared to anatomical designs that properly articulate with both the capitellum and lateral trochlear ridge 5.
The close geometric match between these two surfaces explains why the radial head can potentially serve as an osteochondral autograft for capitellar reconstruction in complex fracture scenarios 1.