A transferring apparatus transfers an article to be processed, which is carried by a carrier device, to a holder provided in a processing chamber defined by a processing vessel and adapted to hold the article at a specified processing position. Various tools may be inserted into the channels in order to perform surgical techniques within the body, such as within the gastrointestinal tract of the patient. The lines of flexure include grooves formed in walls of the attachment portion and thinned and rounded corner regions of the attachment portion.