Final answer:
The radius and ulna bones are crucial for forearm movement and stability.
The ulna forms the elbow joint and attaches muscles, while the radius allows for hand rotation via the wrist joint. Both bones are connected by the interosseous membrane.
Step-by-step explanation:
The functions of the radius and ulna bones are vital for the movement and stability of the forearm.
The ulna is located on the medial side (pinky-finger side) of the forearm and plays a key role in forming the elbow joint as it articulates with the humerus. It provides a stable attachment site for muscles that flex and extend the elbow.
The radius is on the lateral side (thumb side) and is responsible for enabling the hand to turn so the palm faces up (supination) or down (pronation).
This is achieved through its articulation with the capitulum of the humerus and the proximal and distal radioulnar joints which allow rotation.
The rotation of the radius and ulna at these joints is essential for the dexterity and versatile movements of the wrist and hand.
The interosseous membrane, a dense connective tissue, joins the radius and ulna along the interosseous borders of these two bones, providing additional stability and a site for muscle attachment.
Additionally, both bones articulate with carpal bones to form the wrist joint, contributing to movements of the hand.