Radius – Universal Learn

Quick Facts about the Radius

Location: Forearm
Bone Type: Long bone
Key Features: Head, neck, body, radial tuberosity, radial styloid process, ulnar notch
Articulation: Humerus, ulna, scaphoid bone, lunate bone
Arterial Supply: Anterior and posterior interosseous arteries, radial artery, ulnar artery

Key Features & Anatomical Relations of the Radius

General Structure: The radius is one of the forearm bones, shorter than the ulna.
Name Origin: “Radius” reflects its capability to rotate around the ulna.
Classification: It is a long bone.
Parts: Proximal part, body, distal part.
Surfaces: Anterior, posterior, and lateral surfaces, along with anterior, posterior, and interosseous borders.
Landmarks: Head, neck, radial tuberosity, radial styloid process, dorsal radial tubercle, ulnar notch.

Location and Articulation

Position: Proximal to the scaphoid and lunate bones, distal to the humerus, lateral to the ulna.
Joints: It forms part of the elbow joint with the humerus, the radioulnar joints with the ulna, and the radiocarpal joint with the scaphoid and lunate bones.

Ossification of the Radius

Ossification Centers: The radius has three primary ossification centers:
- Body: Appears around the eighth week in utero.
- Proximal Part: Emerges within the fourth to fifth years.
- Distal Part: Appears within the first year.
Fusion: The proximal part fuses with the body by the ages of 14-18; the distal part by 17-19 years.

Variations in Radius Anatomy

Accessory Structures: A lunar tubercle may be present on the distal radius in some individuals.

Surface Anatomy of the Radius

Palpable Points:
- Head: Found below the lateral epicondyle of the humerus when the elbow is extended.
- Radial Styloid Process: Located at the anatomical snuff box.
- Surfaces: Anterior, posterior, and lateral surfaces are subcutaneous above the radial styloid process and can be palpated.
- Dorsal Radial Tubercle: Palpable on the dorsolateral side of the wrist.

Clinical Correlates