In the palm of your hand: Prevent hypothenar hammer syndrome


General Manufacturing CCOHS health Safety

Repetitive trauma damages blood vessels in the fingers.

Significant hazard. PHOTO: ADOBE STOCK

People will use the heel of their hand as a tool to push, grind or hammer something solid. This repetitive trauma can lead to a serious condition called hypothenar hammer syndrome, which reduces blood flow to the fingers.

Hypothenar refers to the group of muscles that control the movement of the little finger. Some of these muscles make up the fleshy edge of the palm (hypothenar eminence). Using the palm as a hammer can damage blood vessels, especially the ulnar artery. This artery goes through the fleshy area of the palm and supplies blood to the fingers. Sometimes a single significant episode causes the syndrome.

The most susceptible workers are 40-year-old men. Those most at risk include metal workers, lathe operators, machinists and workers who use vibrating tools.

Symptoms include a pain at the hypothenar eminence and ring finger, pins and needles (paresthesia), loss of feeling, and difficulty holding heavy objects in the affected hand.


The fingers may also become sensitive to cold and change colour.

Diagnosis is based on symptoms, medical history and job history, then confirmed with tests showing the obstruction of the blood vessels.

Preventive steps

Treatments include smoking cessation (it negatively affects blood circulation), using padded protective gloves, and avoiding the cold. Certain drugs will help to restore blood flow. For some cases surgery may be necessary.

Preventive steps include:

• Improving work practices.

• Not using the palm as a hammer to pump, push or twist.

• Not gripping tools such as impact wrenches too tightly.

• Switching tasks regularly or resting hands.

• Using padded protective gloves to avoid the excessive trauma to the heel of the hand while working.

Other activities cause this syndrome, including sports that involve hands and gripping, mountain biking, breakdancing, drumming and weight lifting.

Because this syndrome is relatively uncommon and unrecognized, diagnosis is often missed or delayed. Bring it up with the safety committee to ensure all employees recognize the causes and symptoms, and take preventive measures, at work and at home.

The Canadian Centre for Occupational Health and Safety (CCOHS) in Hamilton contributed this article. CCOHS provides information, training, education, management systems and solutions that support health and safety programs and the prevention of injury and illness in the workplace. Visit

This article originally appeared in the July-August 2019 print issue of PLANT Magazine.




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