In this paper, we propose the first joint watermarking-encryption-compression scheme for the protection of medical images. Its originality is twofold. In a first time, it allows the access to watermarking-based security services from the encrypted and the compressed bitstreams without having to parse them even partially. It becomes possible to trace images and control their reliability (i.e. integrity and authenticity) from both the encrypted and compressed domains. In a second, it stands on the combination of bit-substitution watermarking, JPEG-LS and the AES block cipher in its CBC mode so as to make our scheme compliant with DICOM. Experiments conducted on different medical images modalities (radiographic and retina images) demonstrate the capability of our system to securely make available a message in both encrypted and compressed domains while minimizing the distortion of the image.