Abstract: An auxiliary operating table, which functions primarily to support a patient's arm horizontally outstretched at a 90.degree. angle to the side rail frame of a body table on which the patient is supported during arm or hand surgery. The auxiliary table, which is collapsible, has a rigid table top with outer and inner ends. Its outer end carries a foldable gas spring leg, which is pivoted for movement between table supporting and table collapsed positions, which tends to extend automatically to its full length, which can be forcibly retracted, and which has a foot-pedal-operated leg clamp for holding the table leg in any table-supporting position within its extension-retraction range. Its inner end carries a depending clamping assembly for securing the auxiliary table to and supporting it on the body table. The inner end clamping assembly includes: a rail clamp and an adjustable table clamp. The rail clamp is rigidly securable to the rail.