This is a prospective, single-blinded randomized controlled study. Patient with CTS were randomly assigned to group receiving ultrasound guided steroid injection and group receiving ultrasound guided corticosteroid injection and splinting. The steroid injection was using 1ml of 10 mg (10mg/ml) triamcinolone acetonide (Shincort) mixed with 1 ml of 2% lidocaine hydrochloride (Xylocaine). The inclusion criteria included an age of more than 18 years and typical signs of CTS according to American Academy of Neurology criteria lasting for at least 3 months. The diagnosis of CTS was confirmed by electrophysiological tests.The exclusion criteria included the following: presence of thenar atrophy; existence of disorders such as hypothyroidism, diabetes mellitus, chronic renal failure, or rheumatoid arthritis; any accompanying orthopedic or neurologic disorders that could mimic CTS such as cervical radiculopathy, polyneuropathy, proximal median nerve entrapment, or thoracic outlet syndrome; prior steroid injection into the affected carpal tunnel or carpal tunnel surgery; history of distal radius fracture; pregnancy or lactation; regular use of systemic NSAIDs or corticosteroids; and known allergy to corticosteroids and local anesthetics.