Radius Bone

Forearm Bones

• The ulna is longer than the radius in the forearm.
• The radius bone is curved, resembling a prismatic shape.

Radius Bone Structure

• The radius bone extends from the elbow to the wrist in the forearm.
• The radius joins with the humerus bone at the elbow.
• The corresponding bone to the radius in the lower leg is the tibia.

Radius Bone Features

• The thickest part of the radius bone is at its proximal end.
• The distal end of the radius bone forms articular surfaces for the scaphoid and lunate bones.
• The palpable point on the radial side of the distal end of the radius bone is called the radial styloid process.

Radial Aplasia

• In radial aplasia, the radius bone is missing.

Radius-Ulna Joint

• The radius and ulna bones form a joint at the wrist called the distal radioulnar joint.
• The radius bone articulates with the ulna bone at the wrist.
• The joint between the radius and ulna is called the proximal radioulnar joint.

Carpal Articular Surface

• The carpal articular surface of the radius is triangular in shape.
• The articular surface on the medial side of the distal end of the radius is called the ulnar notch.

Radial Grooves and Processes

• The first groove on the dorsal surface of the distal end of the radius transmits the tendon of the extensor pollicis brevis muscle.
• The process on the lateral surface of the distal end of the radius is called the radial styloid process.

Radial Borders

• The lateral border of the radius separates the volar from the lateral surface.
• The volar border of the radius gives insertion to the pronator quadratus muscle.
• The posterior border of the radius separates the posterior from the lateral surface.

Intersosseous Membrane

• The interosseous membrane is attached to the radius.

Muscle Insertions

• The biceps brachii muscle inserts on the radial tuberosity of the upper extremity of the radius.
• The flexor pollicis longus muscle originates from the anterior surface of the radius.

Ligaments and Muscles

• The volar radiocarpal ligament attaches to the triangular rough surface between the prominent ridge and the inferior border of the volar surface.
• The pronator teres muscle flexes the forearm and pronates the hand.
• The extensor pollicis brevis muscle extends the thumb.

Development and Abnormalities

• The upper epiphysis of the radius fuses with the body at around 17-18 years of age.
• The abductor pollicis longus muscle attaches to the lower quarter of the body of the radius.
• The term for the congenital absence or shortness of the radius is radial aplasia.
• The posterior surface of the radius is covered by the Supinator muscle.

Nutrient Foramen

• The nutrient foramen is located on the lateral surface of the radius.