Final answer:
The radioulnar joint is formed by the head of the radius and the radial notch of the ulna. It allows for rotation of the radius during pronation and supination of the forearm.
Step-by-step explanation:
The radioulnar joint is formed by the articulation between the head of the radius and the radial notch of the ulna. It is a uniaxial pivot joint that allows for rotation of the radius during pronation and supination of the forearm.
During pronation, the radius rotates medially, causing the palm to face downwards. On the other hand, during supination, the radius rotates laterally, causing the palm to face upwards.
The radioulnar joint is an important joint for the movement and function of the forearm, allowing for various activities such as turning a doorknob or using utensils.