underarmarnas

Underarmarna, or forearms in English, are the paired limbs between the elbow and the wrist. They consist of two long bones, the radius and ulna, which run parallel and are connected by an interosseous membrane that allows force transmission and forearm rotation. The upper ends of the radius and ulna articulate with the humerus at the elbow, forming the elbow joint, while the distal ends articulate with the carpal bones at the wrist, contributing to wrist movements.

Anatomically, the forearm is divided into two compartments: the anterior (flexor-pronator) compartment and the posterior (extensor-supinator) compartment, enclosed by fascial sheaths and retinacula. Most flexor muscles originate from the medial side of the elbow, and most extensor muscles from the lateral side; nerves and vessels supply these compartments. The median and ulnar nerves predominantly innervate the anterior compartment, while the radial nerve supplies the posterior compartment. The brachial artery gives rise to the radial and ulnar arteries, which run with the corresponding nerves along the forearm.

Functionally, the forearms enable flexion, extension, pronation, and supination of the forearm and wrist, providing grip strength and dexterity for daily tasks. They also serve as a transmission link between the upper arm and hand, supporting precision and endurance in activities requiring coordinated arm movements.

Common injuries include fractures of the radius and/or ulna, dislocations at the elbow or radioulnar joints, and forearm compartment syndrome in severe trauma. Tendinopathies such as lateral epicondylitis can affect forearm function.