The patient complains of pain, tingling, or a "pins and
needles" sensation in the hand. Onset may have been abrupt
or gradual but the problem is most noticeable upon awakening
or after extended use of the hand. The sensation may be
bilateral, may include pain in the wrist, or forearm and is
usually ascribed to the entire hand until specific physical
examination localizes it to the median nerve distribution.
More established cases may include weakness of the thumb and
atrophy of the thenar eminence.
Physical examination localizes paresthesia and decreased
sensation to the median distribution (which may vary) and
motor weakness, if present, to intrinsic muscles with median
innervation. Innervation varies widely, but the muscles most
reliably innervated by the median nerve are the abductors
and opponens of the thumb
What to do:
Perform and document a complete examination, sketching the
area of decreased sensation and grading (on a scale of 1-5)
the strength of the hand.
Hold the wrist flexed at 90 degrees for 60 seconds, to see
if this reproduces symptoms. This is known as Phalen's test,
and is more sensitive than the reverse (hyperextending the
wrist) and more specific than tapping over the volar carpal
ligament to elicit paresthesia (Tinel's sign).
Explain the nerve-compression etiology to the patient, and
arrange for additional evaluation and followup. Borderline
diagnoses may be established with electromyography (EMG),
but cases with pronounced pain or weakness may require early
surgical decompression. Anti-inflammatory medication,
elevation of the affected hand, ice, immobilization with a
volar splint, and rest may all help to reduce symptoms.
What not to do:
Do not rule out thumb weakness just because the thumb can
touch the little finger. Thumb flexors may be innervated by
the ulnar nerve. Test abduction and opposition: can the
thumb rise from the plane of the palm and can the thumb pad
meet the little finger pad?
Do not diagnose carpal tunnel syndrome solely on the basis
of a positive Tinel's sign. Paresthesia can be produced in
the d1stribution of any nerve if one taps hard enough.
There is little space to spare where the median nerve and
digit flexors pass beneath the volar carpal ligament, and a
very little swelling may produce this specific neuropathy.
Trauma, arthritis pregnancy, and weight gain are among the
many factors which can precipitate this syndrome.
Less commonly, the median nerve can be entrapped more
proximally, where it enters the medial antecubital fossa
through the pronator teres. Symptoms of this cubital tunnel
syndrome may be reproduced with elbow extension and forearm