midforearm

The midforearm is the middle third of the forearm, extending between the elbow and wrist. It contains the radius and ulna, connected by the interosseous membrane, and lies within the forearm's two main fascial compartments: the anterior (flexor‑pronator) compartment and the posterior (extensor‑supinator) compartment. These muscles, along with nerves and vessels, form the functional core of the region. Proximal to the midline lie the elbow structures; distally are the carpal bones of the wrist. The midforearm also serves as a conduit for neurovascular structures entering the hand.

Muscles in the midforearm are organized into two compartments: the anterior compartment, which primarily flexes the wrist and fingers and pronates the forearm; and the posterior compartment, which extends the wrist and fingers and supinates the forearm. The radial nerve traverses the lateral aspect of the forearm and typically divides into the superficial and deep (posterior interosseous) branches in or near the midforearm. The median nerve runs toward the anterior compartment, while the ulnar nerve remains medially. Blood supply comes from branches of the radial and ulnar arteries, with perforating branches supplying the surrounding tissues.

Clinically, the midforearm is a common site for fractures of the radius and ulna in the middle third, which may involve both bones (two-bone fractures) or isolated injuries. These injuries risk neurovascular compromise and compartment syndrome, and they require imaging for assessment and appropriate management, which may include immobilization or surgical fixation. Knowledge of the midforearm's anatomy is essential for surgical approaches and for predicting potential complications such as nerve injury or malunion.