Radius

What is the radius

A long bone, the lateral bone of the forearm.

Articulations

• Head of radius with radial notch of the ulna form the superior radioulnar joint

• Head of radius with capitulum of humerus to form lateral part of elbow joint

• Distal end of radius with head of ulna to form inferior radioulnar joint Distal end

• Distal end of radius with scaphoid and lunate to form part of the wrist joint

Features of proximal end

• Head - rounded, concave surface

• Neck - narrow, inferior to head

• Radial tuberosity - medial aspect, inferior to neck. Provides attachment for tendon of bicep muscle

Features of shaft

• Anterior, posterior and interosseous border - attached to lateral part of ulna by interosseous membrane to form middle radioulnar joint Head

• Anterior, posterior and lateral surface - location of nutrient foramen

Features of distal end

• Ulnar notch - on medial aspect, articulates with head of ulna to form inferior radioulnar joint

• Radial styloid process - prominent process on lateral aspect that can easily be palpated

• Listers tubercle - palpable process on dorsal aspect

• Distal surface - 2 fossae, separated by a ridge, for articulation with scaphoid and lunate

Ossification

• Shaft at eighth week of intrauterine life

• Distal end at age one, fuses with shaft age seventeen to nineteen

• Head of radius at age four to five, fuses with shaft at fourteen to seventeen

diagram