College of Massage Therapists of British Columbia (CMTBC) Practice Exam

Which nerve is typically compressed in carpal tunnel syndrome?

1. Radial Nerve

2. Ulnar Nerve

3. Median Nerve

4. Axillary Nerve

The correct answer is: Median Nerve

Carpal tunnel syndrome is characterized by the compression of the median nerve as it passes through the carpal tunnel, a narrow passageway located on the palm side of the wrist. The median nerve provides sensation to the palmar side of the thumb, index, middle, and part of the ring finger, and it also innervates muscles that control fine motor skills in the hand. When there is swelling or a structural issue within the carpal tunnel—such as inflammation, repetitive movements, or fluid retention—the space can become constricted, leading to increased pressure on the median nerve. This pressure can result in symptoms such as pain, numbness, tingling, and weakness in the affected fingers, impairing hand function. In contrast, the other nerves mentioned—radial, ulnar, and axillary—have different pathways and roles. The radial nerve primarily innervates the posterior arm and forearm, controlling extension and sensation in those areas. The ulnar nerve, on the other hand, runs along the inner side of the arm and hand, affecting the little finger and part of the ring finger, with symptoms associated with ulnar nerve entrapment manifesting differently, typically due to compression at the elbow. The ax