There are many factors that cause pain on the ulnar side of the palm. When people fall, they often hyperextend their wrists and land on the ulnar side of their palms, which can cause injuries to the ulnar side of the palm. Workers who use heavy hammers or pneumatic drills are prone to injuries to the hypothenar region of the palm. These injuries can cause fractures of the hook of the hamate or pisiform bones, dislocations of the pisiform and triquetrum bones, tears of the lunotriquetral ligament, ulnar artery aneurysms and arterial thrombosis, and damage to the ulnar nerve, which are the main factors for ulnar nerve compression at the wrist. In addition, space-occupying lesions, scar contractures, abnormal muscles, and neuromas can also cause ulnar nerve compression.