Radius 3d Anatomy

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Radius 3d Anatomy

Anatomy of the Radius

Did you ever wonder why this bone is called the radius?

Whenever the forearm pronates or supinates, the Radius rotates relative to the more fixed ulna, which gives the name Radius to this bone. You can see the comparison here in this pic. Comparison between Radius Bone and Radius of a circle

This is the smallest of all the arm bones, namely Radius, Ulna and the Humerus. The Radius ossifies in three centers,

  1. Proximal Epiphysis
  2. Shaft
  3. Distal Epiphysis Radius bone ossifies in three centers


Proximally, the Radius articulates with the capitulum of the humerus. Distally it articulates with the two carpal bones, the Lunate medially and Scaphoid Laterally. Radius also articulates with the Ulna medially on both the proximal and distal ends.

Head of the Radius

The proximal end of the radius has a round articular surface that articulates with the humerus and the ulna.
Image showing Head of the Radius This cupped surface is called the Articular facet or Articular fovea. The humerus is attached here. Proximal End of radius showing the articular surface This part is the articular circumference. The Radius is attached medially with the radial notch of ulna here.

Neck of the Radius

This part between the radial head and the radial tuberosity is termed the Neck of the Radius. Neck of the radius is between the radial head and radial tuberosity

Radial Tuberosity or Bicipital Tuberosity

This blunt protuberance on the anteromedial side is called the Radial Tuberosity or Bicipital Tuberosity. This process is present in the proximal radius and starts after the radial neck. This is where the biceps brachialis is attached. Radial Tuberosity or Bicipital Tuberosity

Shaft of the Radius

Shaft of the Radius This thin and long segment extending from the radial tuberosity to the distal part of the radius is called the shaft. Three borders divide the shaft into three surfaces.


1. Anterior Border

The anterior border extends from the anterior oblique line to the suprastyloid crest. Anterior border of radius extending from the anterior oblique line to the suprastyloid crest

2. Posterior Border

The posterior border is along the posterior aspect and extends from the posterior oblique line to the dorsal tubercle. posterior border extends from the posterior oblique line to the dorsal tubercle

3. Interosseous Border

This sharp edge of the radius is seen on its medial aspect. This is where the interosseous membrane is attached. interosseous border is the sharp border on medial aspect, where interosseous membrane is attached


Image showing various surfaces of the radius

1. Anterior Surface

The anterior surface lies between the anterior and interosseous borders. Anterior Surface of Radius

2. Posterior Surface

The posterior surface lies between the posterior and interosseous borders. Posterior Surface of Radius

3. Lateral Surface

The lateral surface is the area between the anterior and posterior borders. Lateral Surface of Radius

Anterior Oblique Line

The Anterior Oblique line begins from the radial tuberosity anteriorly and spirals inferolaterally and gives origin to the extrinsic muscles of the hand. Anterior Oblique line - gives origin to the extrinsic muscles of the hand

Posterior Oblique Line

The Posterior Oblique line begins from the radial tuberosity posteriorly and spirals down to the tuberosity for the pronator teres muscle.

Nutrient Foramen

The nutrient foramen of the Radius is present on the anterior surface of the proximal radius and exits the bone towards its distal end.

Ulnar Notch

On the distal part of the radius is the articular hollow which is concave in shape. The distal end of the ulna articulates with the distal radius at this concave ulnar notch. Ulnar Notch

Carpal Articular Surface

The carpal articular surface also termed the distal articular surface of the radius is the distal-most part of the radius, which articulates with the lunate bone on the medial side and the scaphoid bone on the lateral side.

Styloid process

The lateral part of the radius has a sharp projection in its distal part. This is termed the Styloid process or Radial Styloid.

Suprastyloid Crest

The Suprastyloid crest is an oblique crest running from the styloid process. Brachioradialis muscle is attached here.

Lister’s tubercle

The distal radius has a large tuberosity called the dorsal tubercle or Lister’s tubercle. It is located on the posterior surface. Ulnar Notch

Grooves for tendons:

Extensor muscle tendons:

These tendons pass through the posterior surface in the broad depression located on the medial side of the Radius.

Extensor Pollicis Longus:

This tendon passes medial to the Lister’s Tubercle.

Extensor Carpi Radialis:

Passes lateral to the Lister’s Tubercle.

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