The Surgeon General heads the SAMHS and has the rank of Lieutenant-General. The SAMHS operates three Military Hospitals; one in Pretoria, one in Cape Town and one in Bloemfontein. There are also four specialized institutes - the Institute for Aviation Medicine, the Institute for Maritime Medicine, the Military Veterinary Institute and the Military Psychological Institute. Together, these units provide comprehensive medical care for military personnel and their dependents, as well as the police and employees of other security-related government departments, and occasionally to neighboring countries. The SAMHS also provides extensive veterinary services for animals (mainly horses and dogs) used by the security and correctional services. The Institute for Aviation Medicine and the Institute for Maritime Medicine screen pilot candidates for the air force and for civilian aviation certification, as well as divers and submariners for the navy. The military's medical services also include general medical and dental care, and specialized rehabilitation services.