The present invention relates to an articulated arm (100) comprising at least three articulations mounted in series in order to allow movements on at least two rotation axes by articulation, characterized in that each articulation (1) comprises a first (2) and second (3) support and at least three linear actuators (10), each linear actuator (10) having a first and second end articulated respectively on the first (2) and second (3) supports by means of a swivel connection (41, 42, 43, 44) and in that it comprises a deformable fluidtight sheath (200) enveloping at least a plurality of articulations and having a volume enabling it, in any circumstance, to follow the movements imparted by the articulated arm.