The profunda artery and radial nerve

The profunda artery and radial nerve exit the triangular interval between the long head of the triceps and the humerus and travel in the spiral groove distally. The nerve crosses the spiral groove and pierces the intermuscular septa 7.5cm proximal to the elbow joint. In this region, the nerve is at risk of injury during humeral shaft fractures. A radial nerve palsy would present with an inability to extend the wrist, thumb, and fingers. The vast majority (80-90%) of radial nerve injuries in the setting of humeral shaft fractures recover with expectant management, and as such radial nerve injury is not an indication for operative management.