Ulnar nerve

The ulnar nerve is one of the main nerves of the arm. It starts in the armpit as a branch of the brachial plexus, carrying fibres from the C8 and T1 nerve roots, runs down the inside of the upper arm, passes behind the elbow in a small groove between the bony bump on the inner side of the elbow and the point of the elbow, and continues down the forearm into the hand (TeachMeAnatomy). It is the nerve you hit when you bang your “funny bone” (Swansea Bay UHB).

What does the ulnar nerve do?

• Feeling: it supplies the little finger, the half of the ring finger next to it and the matching part of the palm and back of the hand.
• Movement: it supplies two muscles in the forearm that bend the wrist and the ring and little fingers, and most of the small muscles inside the hand (TeachMeAnatomy).

So when it is irritated, symptoms tend to show up on the little-finger side of the hand. Carpal tunnel syndrome is pressure on a different nerve, at the wrist (NHS).

Why the elbow is the ulnar nerve’s weak spot

At the elbow there is very little padding, so the nerve lies close to the skin. It passes through a narrow passage called the cubital tunnel, where it can be squashed, stretched or irritated: cubital tunnel syndrome (Swansea Bay UHB). Trapping of the ulnar nerve at the elbow is the second most common nerve entrapment after carpal tunnel syndrome (Caliandro et al., 2016).

Bending the elbow makes the space tighter. In 20 cadaver specimens, moving the elbow from straight to fully bent shrank the tunnel by 30 to 41% and the nerve itself by 33 to 50%, and from 90 degrees of bending onwards the pressure inside the nerve was higher than the pressure around it (Gelberman et al., 1998). These were cadavers, not living people.

Typical symptoms are pain, pins and needles or numbness in the forearm and the ring and little fingers. In more severe cases the hand becomes weak, holding and handling things gets harder, the muscles waste and the fingers can curl into a claw (Swansea Bay UHB; Leeds Community Healthcare).

Leaning on your elbow at a desk

NHS physiotherapy services list everyday habits that keep the elbow bent or press on it: leaning on the elbow, resting the arms on an armrest for a long while, typing or texting for long periods, holding a phone or tablet up for a long time, and sleeping with the elbow bent. They suggest checking your workspace so that your chair height suits the desk and your arm is supported without too much pressure or elbow bend (Swansea Bay UHB; Leeds Community Healthcare). For the set-up itself, see how to set up your office chair and the workstation checklist.

What the research says about desk work

Whether computer work itself causes ulnar nerve problems is unsettled. A 2025 review found a possible link, but no consensus (Vulpoi et al., 2025). In 62 people referred for nerve tests, years of computer work were not linked with ulnar nerve findings once age and sex were taken into account, though the group was small (Vulpoi et al., 2026). In 598 workers with repetitive jobs followed for three years, the risk factors were holding a tool in position and obesity (Descatha et al., 2004).

The advice to change habits does have some trial support. In the one trial in a Cochrane review that tested advice for mild or moderate cases, with 51 people, information on avoiding prolonged positions and movements improved discomfort, and adding night splints or nerve gliding exercises brought no extra benefit (Caliandro et al., 2016).

When to see a doctor

See a GP if you have pins and needles all the time or they keep coming back (NHS), or if your hand feels weak or clumsy; a nerve conduction test may be needed (Swansea Bay UHB). Similar symptoms can also come from the neck (Swansea Bay UHB), so ask for an urgent appointment or contact NHS 111 if pins and needles in an arm come with neck or arm pain, or your arms or legs feel heavy or weak (NHS); see radiculopathy. Call 999 if someone’s face droops on one side, they can’t lift both arms or their speech is slurred (NHS).