käsivartta

Käsivartta is the forearm, the part of the upper limb between the elbow and the wrist. In humans it contains two long bones, the radius and ulna, connected by an interosseous membrane, and is organized into an anterior (flexor) and a posterior (extensor) compartment.

The forearm articulates with the upper arm at the elbow (humeroulnar and humeroradial joints) and with the wrist at the radiocarpal joint. It houses important nerves and vessels, including the median, ulnar, and radial nerves, and the radial and ulnar arteries. The musculature controls movements of the wrist and fingers, with the pronator teres and other pronators enabling pronation, and the supinator and extensor/ flexor groups enabling supination and flexion or extension of the joints.

Functionally, the forearm enables rotation of the hand (pronation and supination) and supports wrist and finger movements, contributing to grip and manipulation tasks. It also serves as a conduit for neurovascular structures passing to the hand.

Clinical relevance includes forearm fractures, which can involve the radius, ulna, or both. Distal radius fractures (often called Colles fractures) and injuries such as Monteggia and Galeazzi lesions are common. Forearm injuries can risk nerve or vascular damage and may require immobilization or surgical fixation. Compartment syndrome is a potential emergency following crush or severe trauma.

Diagnosis typically relies on X-ray imaging; MRI or CT may be used for complex cases. Treatment decisions depend on fracture location and severity, and on neurovascular status, aiming to restore alignment and function of the forearm and hand.