Cubital Tunnel Syndrome
Cubital tunnel syndrome refers to irritation or injury of the ulnar nerve as it courses through a tunnel called the
cubital tunnel on the inside of the elbow (the side facing a person's body). The cubital tunnel is comprised of
bone and ligament and is therefore rigid. The ulnar nerve in this location is informally termed the "funny bone"
and bumping it results in an electrical sensation shooting down to the small and ring fingers. The ulnar nerve
provides feeling to the small finger and the side of the ring finger that faces the small finger. It also supplies many
of the muscles of the hand.
The ulnar nerve may be injured by the transmission of external pressure or vibration to the nerve. Pressure may
occur from placing the inside of the elbow against an object. Vibration may occur from operating power garden
tools. The ulnar nerve may sustain stretch (traction) injury when the elbow is held bent (flexed) for prolonged
periods of time such as holding a telephone to one's ear.
Ulnar nerve irritation or injury may present with pain, numbness, or tingling involving the small finger side of the
palm and the small finger and the side of the ring finger facing the small fingers. More serious ulnar nerve
compression may be associated with hand grip weakness. Some of the muscles may shrink in size (atrophy) due
to ulnar neuropathy. The most noticeable muscle atrophy involves the small finger side of the palm and the area
of the hand between the thumb and index fingers.
Some simple physical exam tests can be done to help determine if a person has cubital tunnel syndrome. Tinel's
sign is performed by tapping a finger tip over the cubital tunnel. The cubital tunnel compression test is performed
by placing finger pressure over the cubital tunnel. The elbow flexion test is performed by holding the elbow bent
(flexed). These tests are considered positive for cubital tunnel syndrome if they result in precipitation or
aggravation of pain and numbness radiating into the small finger and the side of the ring finger facing the small
More specialized tests to confirm the diagnosis of cubital tunnel syndrome include injection of steroid and a local
anesthetic (xylocaine) into the cubital tunnel. Symptom relief after a cubital tunnel steroid injection supports a
diagnosis of cubital tunel syndrome.
Nerve conduction tests are a diagnostic test where an electrical stimulus is administered to the upper arm above
the elbow. An electrode is placed around a finger of the hand, usually the small finger. The nerve conduction
instrument measures the time it takes for the electrical stimulus to travel from the stimulating electrode in the
forearm to the recording electrode attached to the finger. The electrical stimulus travels very fast through a
normal nerve. However, the electrical stimulus travels more slowly though injured segments of nerve tissue. The
magnitude and location of the conduction slowing allows determination of the severity and site of nerve injury.
Comparing the rate of conduction resulting from electrical stimuli applied above and below the elbow can help to
localize nerve injury to the cubital tunnel.
It is important to distinguish between Guyon's canal syndrome (ulnar nerve irritation at the wrist) and cubital
tunnel syndrome (ulnar irritation at the elbow) since treatment is different for these two conditions. It is also
important to keep in mind that nerve compression in the neck resulting in cervical radiculopathy can be
associated with symptoms similar to cubital tunnel syndrome.
Qwi Gloves and the Qwi Solution are effective for Guyon's canal syndrome, but will have no effect on cubital
tunnel syndrome or cervical radiculopathy.
Copyright 2005-2012 Etsuko, LLC. All Rights Reserved
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The cubital tunnel is located between the two
black arrows in the photograph on the left.
This is a close-up of the inside of the elbow
(ie, the medial side of the elbow). The path of
the ulnar nerve is depicted by the black line
as it courses through the cubital tunnel.