Carpal tunnel syndrome results from compression of the median nerve at the wrist. It is commonly seen in adults and more frequently in women. Symptoms include pain, numbness and tingling in the hand that is worsened at night. Physical exam findings include a positive Phalen's maneuver, Tinel's sign, and thenar atrophy. Conservative treatments include splinting, oral anti-inflammatories, and local corticosteroid injections. Surgery is considered if symptoms do not improve with conservative care or if nerve conduction studies show severe nerve damage.

1. CARPALTUNNEL SYNDROME
ANATOMY AND IMAGING
Dr SUMIT KUMAR
RADIOLOGY JR 2
PONDICHERRY

2. DEFINITION
Carpal tunnel syndrome, the most common focal
peripheral neuropathy, results from compression of the
median nerve at the wrist.
It is a cause of significant disability, and is one of three
common median nerve entrapment syndromes; the
other two being anterior interosseous nerve
syndrome and
pronator teres syndrome.

3. ANATOMY OF CARPAL
TUNNEL
Boundaries of carpal tunnel:
Volarly : transverse carpal ligament
Dorsally : Carpal bones, deep volar carpal ligaments and volar interoseeous
ligaments
Laterally : scaphoid tuberosity & Trapezium
Medially : Pisiform & hook of hamate
Contents: 9 Tendons and median nerve
Tendons: The tendon of Flexor pollicis longus
4 tendons of Flexor digitorum profundus
4 tendons of Flexor digitorum superficialis
Transverse carpal Ligament : Flexor Retinaculum
Thick fibrous band from the tuberosity of scaphoid & a portion of trapezium to the
Pisiform & hook of hamate.

14. EPIDEMIOLOGY
Affects adult individuals
Three times more common in women than in men
High prevalence rates have been reported in persons
who perform certain repetitive wrist motions (frequent
computer users)

15. CAUSES
Aberrant
Anatomy
- Anomalous flexor tendons
- Congenitally small carpal
canal
- Ganglion cysts
- Lipoma
- Proximal lumbrical
muscle insertion
- Thrombosed artery
Infections
- Septic arthritis
- Mycobacterial infections
- Lyme disease
Inflammatory
conditions
- Flexor tenosynovitis
- Connective tissue diseases
- Gout or pseudogout
- Rheumatoid arthritis
Meatabolic conditions
- Acromegaly
- Hypothyroidism
- Amyloidosis
- Diabetes
Increased canal
volume
- Pregnancy
- Obesity
- Edema
- Congestive heart failure

16. CLINICAL FEATURES
Pain
Numbness
Tingling
Symptoms are usually worse at night
and can awaken patients from sleep.
To relieve the symptoms, patients
often “flick” their wrist as if shaking
down a thermometer (flick sign).

17. Pain and paresthesias may radiate to the forearm, elbow, and
shoulder.
Decreased grip strength may result in loss of dexterity, and
thenar muscle atrophy may develop if the syndrome is severe.
CLINICAL FEATURES

18. DIAGNOSIS
History
Physical examination
Investigation

19. PHYSICAL EXAMINATION
Phalen’s maneuver
Tinel’s sign
Durkan Compression Test

20. CLINICAL FINDINGS
Sensory
disturbance
Weakness in thumb
abduction
Thenar atrophy

21. PHALEN’S MANEUVER
In this test the wrist is flexed upto 90 degrees for a period of one minute.
Patient is then asked for the complaints of tingling, numbness an or pain
in the first 3 fingers.
This test can be quantified by noting the time taken for the symptoms to
appear.
There are several ways of positioning the wrist for eliciting the test.

22. TINEL’S SIGN
Elicitation: Tap over the median nerve as it passes through the carpal
tunnel in the wrist.
Positive response: a sensation of tingling in the distribution of the
median nerve over the hand.

23. DURKAN COMPRESSION
TEST
Gentle pressure directly over carpal tunnel  paraesthesia in 30 seconds
or less
Better for wrists with limited motion
Highest sensitivity/specificity of all physical exam tests

24. SUMMARY OF TESTS
Test Sensitivity Specificity
Phalen’s 75% 62%
Tinel’s 64% 90%
Compression 87% 90%

25. Radiographic features
Ultrasound and MRI are the two imaging modalities which best lend themselves to
investigating entrapment syndromes.
Ultrasound
In imaging median nerve syndromes, ultrasound is useful in examining CTS, potentially
revealing, in fully developed cases, a triad of:
•Palmer bowing of the flexor retinaculum (>2 mm beyond a line
connecting the pisiform and the scaphoid)
•Distal flattening of the nerve
•Enlargement of the nerve proximal to the flexor retinaculum.
Enlargement of the nerve seems to be the most sensitive and specific criterion, but what
cut-off value for pathological size remains debated; normal cross-sectional area is given
at 9-11 mm ², but the range of sizes deemed pathological is wide.

28. MRI
In CTS, MRI can demonstrate
•Palmer bowing of the flexor retinaculum.
•Enlargement of the median nerve at the level
of the pisiform, and flattening of the median
nerve at the level of the hook of the hamate.
•Other signs are edema or loss of fat within
the carpal tunnel, and increased size/edema
of the nerve on water-sensitive sequences.
•Although sensitivity and specificity of mri in
cts are low (23-96% and 39-87%,
respectively),
• MRI is especially well-suited for detecting
masses, arthritic changes, or normal variants.

29. Segmental swelling of median nerve (arrows). Axial MR images (TR 2000,
TE 20) at levels of pisiform (A) and hook of hamate (B). Left wrist viewed
toward elbow with palm down. Note enlargement of nerve proximally (A)
compared with normal caliber of nerve distally (B).

30. AxialT1 etT2FS :T1: enlarged median nerveT2: nerve signal
increase.The normal fascicular appearance of the nerve has

31. DIFFERENTIAL
DIAGNOSTICS
Anterior interossous nerve syndrome
(Kiloh- Nevin syndrome)
Pronater teres syndrome
Kienbock's disease
Compression of the Median nerve at the elbow

32. TREATMENT
CONSERVATIVE TREATMENTS
• GENERAL MEASURES
• WRIST SPLINTS
• ORAL MEDICATIONS
• LOCAL INJECTION
• ULTRASOUND THERAPY
• Predicting the Outcome of Conservative
Treatment
SURGERY

33. GENERAL MEASURES
Avoid repetitive wrist and hand motions
that may exacerbate symptoms or make
symptom relief difficult to achieve.
Not to use vibratory tools
Ergonomic measures to relieve
symptoms depending on the motion that
needs to be minimized

34. LOCAL INJECTION
A mixture of 10 to 20 mg of
lidocaine (Xylocaine) without
epinephrine and 20 to 40 mg of
methylprednisolone acetate
(Depo-Medrol) or similar
corticosteroid preparation is
injected with a 25-gauge needle at
the distal wrist crease (or 1 cm
proximal to it).

35. LOCAL INJECTION
Splinting is generally recommended after local corticosteroid
injection.
If the first injection is successful, a repeat injection can be
considered after a few months
Surgery should be considered if a patient needs more than
two injections

36. ULTRASOUND THERAPY
•May be beneficial in the long term management
•More studies are needed to confirm it’s usefulness

37. SURGERY
Indications:
1. No response to conservative
treatment
2. Severe nerve entrapment demonstrated by
Nerve conduction studies
3. Thenar atrophy,
4. Motor weakness.
It is important to note that surgery may be effective even if a patient
has normal nerve conduction studies

38. CONCLUSION
Most common focal peripheral neuropathy
Pain and paresthesias in the distribution of the median nerve are the
classic symptoms.
While Tinel’s sign and a positive Phalen’s maneuver are classic clinical
signs of the syndrome, hypalgesia and weak thumb abduction are more
predictive of abnormal nerve conduction studies.

39. CONCLUSION
Conservative treatment options include splinting the wrist in a
neutral position and ultrasound therapy
local corticosteroid injections may improve symptoms.
If symptoms are refractory to conservative measures or if nerve
conduction studies show severe entrapment, open or endoscopic
carpal tunnel release may be necessary.

40. 