An elongate probe (204) including a probe head (214) with a transducer array (216), a shaft (210) and an articulating member (212). The articulating member is located between the probe head and the shaft. The articulating member is configured to articulate between a position in which the probe head extends along a longitudinal axis of the probe and at least one articulated position in which the probe head extends at a non-zero angle from the longitudinal axis of the probe. The probe further includes a stiffener (224) configured to controllably move from a retracted position to an extended position at which the stiffener inhibits articulation of the articulating member.
