Causes / typical injury mechanism: Hypothenar hammer syndrome is usually the result of chronic, repetitive microtrauma to the ulnar artery near the hypothenar eminence. This microtrauma can result in injury to the artery that can further lead to thrombosis or aneurysm of the artery.

Classic history and presentation:

• The classic patient is a middle-aged man with a job that involves repetitive hand motions / heavy use of the hands
• Pain along the hypothenar eminence
• Pain in the small, ring, and/or middle fingers
• Sensitivity to cold
• With or without ischemia, ulcers, or gangrene in ulnar digits

Prevalence:

• Age – usually seen in individuals between the ages of 40 and 60 years.
• Sex / gender – There is a high prevalence in men compared to women.

Risk factors: Repetitive blunt trauma to the ulnar aspect of the hand.

• Occupations with frequent use of the hands as a hammer, such as carpenter and mechanic.
• Recreational activities, such as sports.

Pathophysiology: Hypothenar hammer syndrome is due to intimal damage to the superficial palmar branch of the ulnar artery, leading to thrombosis or aneurysm. Digital ischemia or gangrene can occur due to distal emboli.