上肢 is the medical/anatomical term covering the entire upper extremity — shoulder, upper arm (
上臂), forearm (
前臂), wrist (
腕), and hand (
手). Its pair is
下肢 (xiàzhī, lower limb). For everyday speech,
胳膊 (gēbo) for 'arm' is more natural;
上肢 belongs in clinics, fitness writing, and rehabilitation contexts.
