Carpal Tunnel Syndrome
Examine this patient's hands.
· Ask the patient about nocturnal pain (commonest cause of hand pain at night).
· History of oral contraceptives, rheumatoid arthritis, myxoedema, acromegaly,
chronic renal failure, sarcoidosis.
· Take a family history (abnormally small size of carpal tunnel runs in families).
· Wasting of the thenar eminence.
· Weakness of flexion, abduction and opposition of thumb.
· Diminished sensation over lateral three and half fingers.
Proceed as follows:
· Look carefully for scar of previous surgery (hidden by the crease of the wrist).
· Percuss over the course of the median nerve in the forearm: patient may
experience tingling - this is Tinel's sign.
· Ask the patient to hyperextend the wrist maximally for 1 minute; this may bring on
symptoms (dysaesthesia over the thumb and lateral two and half fingers).
· Tell the examiner that you would like to:
-Examine for underlying causes such as myxoedema, acromegaly and rheumatoid
Look for cervical spondylosis, frozen shoulder and tennis elbow (these may be
-Look for the Cimino-Brescia fistula for haemodialysis
“Sir, my patient is a middle age lady who appears well. On inspection, both of her
hands are in the normal resting position with the forearm supinated and wrist
extended. The MCP and IP joints are flexed, more pronounced in the little finger and
less in the index finger.
I also notice wasting of the thenar eminence of the left hand; in addition, there is a
3cm scar over the transverse carpal ligament of the right hand signifying possible
previous carpal tunnel release of the right hand.
Abduction of the left thumb is weak, power is grade 3, but power of the long flexors
of the thumb and index finger was full on testing the flexion of the DIP joint of the
index finger. Sensation is intact but decreased over the radial 3 ½ digits of the left
Tinel’s sign is positive over the ventral aspect of the proximal wrist. Phalen test is
positive and patient reported tingling/numbness along the median nerve distribution.
Functionally, she has a weak power grip, pincer grip, unable to button unbutton shirt,
find it difficult to hold a pen & write.
In regards to the etiology of this condition, I was unable to note any evidence of
acromegaly, myxodema, deforming arthropathy (RA), cutaneous stigmata of
pregnancy/abdomen distension, or trauma.
My diagnosis is severe left median nerve palsy secondary to carpal tunnel syndrome.
To complete my examination, I would like to examine for cervical spondylosis which
could have resulted in radiculopathy that may mimic CTS.”
This patient has median nerve involvement of the hand with Tinel's sign (lesion) due
to carpal tunnel syndrome as a complication of chronic haemodialysis (aetiology).
The patient has disabling tingling and pain at night (functional status).
What is carpal tunnel?
Carpal tunnel is a fibro-osseous tunnel situated on the flexor aspect of the proximal
part of the hand and lying between the flexor retinaculum and the carpal bones.
Compression of the median nerve within the carpal tunnel is known as carpal tunnel
What does the carpal tunnel contain?
It contain the median nerve and 10 flexor tendons that include:
(a) 4 tendons of flexor digitorum superficialis.
(b) 4 tendons of flexor digitorum profundus.
(c) Flexor pollicis longus tendon.
(d) Flexor carpi radialis tendon.
Where does the flexor retinaculum attach?
It attach to the tubercle of the scaphoid and pisiform proximally and the hook of the
hamate and trapezium distally. Its function is to prevent bow-stringing of the flexor
tendons at the wrist.
What is positive phalen test?
Patient when ask to hold their wrist in complete and forced flexion reports
tingling/numbness along the median nerve distribution in less than 60 seconds.
What muscle does the median nerve innervate in the hand?
It supply 4 muscles in the hand, mnemonic LOAF :
Lateral 2 lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis.
Would you expect numbness over the thenar eminence in carpal tunnel syndrome?
No, because the palmar cutaneous branch of median nerve is given off 5cm proximal
to the wrist and then passes superficial to the carpal tunnel.
How would you treat this condition?
Diuretics, wrist splint & Ultrasound treatment, local steroid injection, surgical
decompression (open or endoscopic).
How would you confirm your diagnosis?
Nerve conduction study will show impaired median nerve conduction across the
carpal tunnel in the context of normal conduction elsewhere. Nerve compression
results in damage to the myelin sheath and manifests as delayed distal latencies and
slowed conduction velocities. With sustained or more severe compression, axon loss
may also occur, resulting in a reduction of the median nerve compound motor or
sensory action potential amplitude.
What is Phalen’s test?
Patient is asked to keep both wrist in complete palmar flexion for 1 minute, this
produces numbness or tingling in the distribution of the median nerve.
What are the causes of median nerve neuropathy in the axilla and upper arm?
Axilla : Compression by crutches, sleep palsy, missile & stab injuries, anterior
shoulder dislocation, fascial sheath hemorrhage, false aneurysm.
Upper arm : Arteriovenous fistulas, stab wounds, fractures of the humerus,
tourniquets, sleep palsy.
Mention a few causes of carpal tunnel syndrome.
In chronic renal failure patients on long-term dialysis it is due to [β2-microglobulin as
Amyloidosis (e.g. due to multiple myeloma).
How would you treat this condition?
2. Wrist splint and ultrasound treatment
3. Local steroid injection should be given proximal to the carpal tunnel (not into
the tunnel because it may damage the nerve)
4. Surgical decompression.
How would you confirm the diagnosis?
Nerve conduction studies (increased latency at the wrist on stimulation of the
median nerve; the muscle action potential from abductor pollicis brevis is a valuable
diagnostic sign). Rarely, the proximal latency may be normal with a prolonged distal
latency due to an anastomosis between the ulnar and median nerves in the forearm.
A negative test thus does not rule the syndrome out
absolutely but calls it into question.
Mention a few clinical diagnostic tests
· Wrist extension test: the patient is asked to extend his wrists for I minute; this
should produce numbness or tingling in the
distribution of the median nerve.
· Phalen's test: the patient is asked to keep both hands with the wrist in complete
palmar flexion for I minute; this produces
numbness or tingling in the distribution of the median nerve.
· Tourniquet test: the symptoms are produced when the blood pressure cuff is
inflated above the systolic pressure.
· Pressure test: if pressure is placed where the median nerve leaves the carpal tunnel,
it causes pain.
· Luthy's sign: if the skinfold between the thumb and index finger does not close
tightly around a bottle or cup because of thumb
abduction paresis, this test is regarded as positive.
· Durkan's test: direct pressure over the carpal tunnel - the carpal compression test is more sensitive and specific than the Tinel
and Phalen sign.
Mention other entrapment neuropathies.
· Meralgia paraesthetica (lateral cutaneous nerve of the thigh trapped under the
· Elbow tunnel syndrome (ulnar nerve trapped in the cubital tunnel)
· Common peroneal nerve trapped at the head of the fibula
· Morton's metatarsalgia (trapped medial and lateral plantar nerves causing pain
between third and fourth toes).
· Tarsal tunnel syndrome (posterior tibial nerve is trapped).
· Suprascapular nerve trapped in the spinoglenoid notch.
· Radial nerve trapped in the humeral groove.
· Anterior interosseous nerve trapped between the heads of the pronator muscle.
Carpal tunnel release
Positioning: Supine with side arm table, palm upright.
Prep: Betadine scrub, then paint (or chloroprep)
Identify landmarks: distal crease (stay above this), in line with palmaris longus
tendon and web space (3&4).
Draw plumb line from 3rd – 4th interspace down through midline of palm.
Incision will be on the ulnar side of the midline palmar crease. Stay under cardinal
line and above distal crease.
Infiltrate local anesthetic
Incise using 15 blade, cut 3-4 cm.
Cut down with 15 blade to palmar aponeurosis and open sharply.
Place Intern retractor.
Continue with 15 blade to Transverse Carpal Ligament (TCL), cut through it layer by
Using Penfield 4 to dissect the space above the nerve and TCL.
Open the remaining portion of the TCL distally into the wrist using scissors. Once
fully opened, the Penfield 4 will pass freely into the wrist.
Close palmar aponeurosis using 4-0 vicryl.
Close dermis/fat with 4-0 vicryl, then 3-0 nylon running for skin.
Cover with Xeroform over the incision, then fluffs in palm. Wrap with Kerlix and
loose Ace wrap in slight extension. May remove in 3 days (typically).
UMS Orthopedic Short Cases Records 1st edition
Baliga 250 cases in internal medicine