Task: Question Answering
Input (English): Context: Carpal tunnel syndrome (CTS) is a focal compressive neuropathy of the median nerve at the level of the wrist. CTS is the most common type of compressive neuropathy that occurs in the upper extremity. Typically, patients with CTS have paresthesia, pain, and numbness in the radial three and one-half digits. Nighttime symptoms are more common earlier in the disease process, with daytime symptoms becoming more frequent as CTS progresses. Electrodiagnostic studies may be performed to confirm a diagnosis of CTS or to obtain a baseline before surgical treatment; however, electrodiagnostic studies may be normal in a subset of patients who have CTS. Patients who have mild CTS should undergo an initial trial of nonsurgical treatment that includes lifestyle modifications, nighttime splinting, and corticosteroid injections. Carpal tunnel release should be performed in patients in whom nonsurgical treatment fails and patients who have acute CTS secondary to infection or trauma or have advanced symptoms. Recalcitrant CTS, which may occur in as many as 25% of patients who undergo carpal tunnel release, most commonly results from an incomplete transverse carpal ligament release or an incorrect initial diagnosis. Patients with recurrent symptoms often have perineural fibrosis that tethers the median nerve. 
 Question: What nerve is involved in carpal tunnel syndrome?
Output (English): median