Wrist

Carpal Tunnel Syndrome

Name: Carpal Tunnel Syndrome
Creator: Dr. Kwang Lee

수근관 증후군

Median nerve compression in the carpal tunnel causing thumb-index-middle finger numbness and thenar muscle weakness

Written and edited by Dr. Kwang Lee, D.C., L.Ac. · Updated 2026-10-04

How common: Very common
Typical age: Ages 30–60

What is it?

Elevated carpal tunnel pressure compresses median nerve → sensory-motor dysfunction in median nerve distribution (thumb-index-middle-radial ring finger)

Commonly affected: Median nerve (within carpal tunnel), thenar muscles (opponens pollicis, APB, FPB)

How it develops

Carpal Tunnel AnatomyCarpal tunnel is a narrow channel formed by carpal bones (roof) and transverse carpal ligament (floor) — median nerve and 9 flexor tendons pass through
Pressure IncreaseElevated carpal tunnel pressure (normal 7-8mmHg → >30mmHg in CTS). Flexor tendon thickening, edema, mass, systemic factors
Neural IschemiaPersistent compression reduces intraneural blood flow → neural ischemia → demyelination
Sensorimotor DysfunctionMedian nerve damage → 1st-3rd finger numbness, thenar weakness (in advanced cases)

Symptoms

Nocturnal Numbness (Fingers 1-3)Sleep disrupted by thumb-index-middle finger numbness — median nerve distribution
Flick SignShaking hand temporarily relieves numbness — highly specific for CTS
Thenar WeaknessAdvanced: thenar muscle weakness and atrophy → weak thumb opposition
Activity-Related WorseningWorsens with repetitive wrist flexion/extension work, driving, reading

How it is examined

Phalen's TestFull wrist flexion with both hands held 60 seconds → reproduces thumb-index-middle finger numbness → Positive (sensitivity 80%)
Tinel's Sign (Wrist)Tapping carpal tunnel at wrist → electric shock in 1st-3rd fingers → Positive (high specificity)
Thenar Atrophy AssessmentThenar atrophy visible in advanced CTS — APB (abductor pollicis brevis) especially affected
Two-Point DiscriminationQuantitative sensory assessment in median nerve distribution — normal ≤5mm

Imaging

Exclude secondary causes such as OA, fracture, or mass

Usually normal
Identify structures narrowing carpal tunnel
Rheumatoid arthritis findings if present

Confirm median nerve compression and evaluate secondary causes (mass, ganglion) — supplements nerve conduction study

Median nerve thickening and T2 hyperintensity
Carpal tunnel effusion or mass
Median nerve flattening

Non-surgical care

Wrist Splint (Night)Neutral wrist position splint — most effective when worn at night. Minimizes carpal tunnel pressure
Activity ModificationAvoid repetitive wrist flexion/extension, ergonomic keyboard/mouse
Steroid InjectionIntracarpal tunnel steroid injection — short-term (3-6 months) effect. Especially useful in pregnancy or mild cases
Systemic TreatmentTreat underlying conditions: pregnancy, hypothyroidism, diabetes

Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.

When surgery is considered

Failed conservative treatment >3 months, thenar weakness/atrophy, severe nerve conduction abnormalities

Procedures that may be discussed

Carpal tunnel release — transverse carpal ligament division. Open or endoscopic
Endoscopic surgery has fewer wound complications and faster recovery

Outlook

90-95% symptom improvement after surgery. Thenar atrophy recovers gradually over 1-2 years