A limb prosthesis including a palm, a forearm, an upper arm, an elbow joint and a wrist joint is provided. The palm has a first axle and a first screw set. The upper arm has a socket. The elbow joint connects the forearm and the upper arm. The wrist joint connects the palm and the forearm. The wrist joint has a first linkage connected to the forearm. The first axle rotatably passes through the first linkage. The first screw set is screwed to the first axle. A first wedge surface of the first screw set is used to contact a second wedge surface of the first linkage. By adjusting a distance between the first screw set and the first axle, magnitude of a force applied between the first wedge surface and the second wedge surface can be adjusted, so as to make the palm to be fixed relative to the first axle or rotated about an axial direction. The axial direction is vertical to an extending direction of the forearm.一種義肢，包括一手掌、一前臂、一上臂、一肘關節以及一腕關節。手掌具有一第一轉軸與一第一鎖附組。上臂具有一承窩。肘關節連接前臂及上臂。腕關節連接手掌與前臂。腕關節包括一第一連桿。第一連桿連接前臂。第一轉軸可轉動地穿過第一連桿。第一鎖附組鎖附至第一轉軸。第一鎖附組的一第一楔形面用以接觸第一連桿的一第二楔形面。藉由調整第一鎖附組與第一轉軸之間的距離，可調整第一楔形面與第二楔形面之間的正向力的大小，以使手掌相對第一連桿固定或可繞一軸向轉動。軸向垂直前臂的一延伸方向。
