Hypothenar hammer syndrome is damage to the ULNAR ARTERY where it runs across the heel of the palm, caused by repeatedly using the hand as a hammer.
The artery’s wall is injured, a clot or a small aneurysm forms, and fragments travel downstream into the fingers.
The giveaway is that the ring and little fingers are affected while the thumb stays completely normal — which is the opposite of what almost every other hand condition does.
Thumb spared, ulnar fingers cold. That pattern is worth memorizing.
Why the heel of the palm
The ulnar artery passes over the hook of the hamate, a projecting bone in the palm, covered by very little tissue.
Strike that area repeatedly — pushing, pounding, jarring — and the artery is compressed against bone with each impact.
Classic exposures: mechanics using the palm to seat parts, carpenters, machinists, martial artists, mountain bikers, volleyball and handball players, anyone using a jackhammer or push-starting heavy machinery.
Almost always the dominant hand. Overwhelmingly men, typically 30 to 50.
The same repeated trauma to the same spot can also fracture the bone itself — see hook of hamate fracture. Bone and artery, same location, entirely different presentations.
What it presents as
- Cold intolerance and color change in the ring and little fingers, one hand only
- Pain, numbness or tingling in those fingers
- A tender, sometimes pulsatile lump in the heel of the palm
- Delayed capillary refill in the affected fingers
- In advanced cases, fingertip ulcers, splinter hemorrhages, or frank tissue loss
Unilateral Raynaud’s in a man who works with his hands is hypothenar hammer syndrome until an artery has been imaged.
The Allen’s test — occluding both arteries, then releasing the ulnar — is the bedside screen and is usually abnormal. Confirmation is by duplex ultrasound, CT angiography or MR angiography.
What it gets mistaken for
Raynaud’s phenomenon. But primary Raynaud’s is bilateral and symmetrical. One hand only, in the dominant arm, is not Raynaud’s.
Guyon’s canal syndrome. Same fingers, same region — but that is nerve compression, so it produces numbness and weakness without color change or cold intolerance. The two can coexist, because the nerve and artery travel together.
Vibration white finger. Usually bilateral, and driven by tool vibration rather than impact.
Treatment
Stop the trauma. Non-negotiable and permanent. Padded gloves, padded tool handles, and above all never using the palm as a mallet again.
Medical management for mild cases without tissue loss: smoking cessation, cold avoidance, calcium channel blockers, antiplatelet agents. Thrombolysis is used in selected acute cases.
Surgery where there is an aneurysm, ongoing embolisation, or threatened tissue.
- Resection of the damaged segment with vein graft reconstruction is the usual approach
- Simple ligation is an option where the radial supply to the hand is demonstrably adequate
- Week 0 to 2: protected, wound healing
- Week 2 to 6: motion and gradual use
- Month 3 to 6: return to work, with the causative activity permanently modified
Returning to the same hammering habit after reconstruction reliably reproduces the condition. The operation fixes the artery, not the behavior.
The window
- Cold intolerance only: excellent outcomes, often no surgery needed
- Recurrent embolisation: treat before tissue is lost
- Fingertip ulceration: urgent vascular referral
- Established tissue necrosis: amputation of a fingertip becomes a real possibility
Most people reading this have spent years using the base of their palm as a free tool that came with the job. It was never free.
Related reading
- Hook of Hamate Fracture: The Bone Break Most Standard X-Rays Miss
- Guyon’s Canal Syndrome: Ulnar Nerve at the Wrist
- Raynaud’s in the Hands: White, Blue, Red, and What It Means
- Cycling Hand Numbness: Handlebar Palsy and How to Stop It
Every article on this site is written using the Closing Window Method: name the window your condition runs on, find where you are in it, and act while it’s still open.