What is Ischemia? Ischemia is the medical term for an inadequate blood supply to a specific area of the body. This results in a reduced oxygen supply as blood has difficulty in reaching the target tissues or organs.Ischemia can be partial or complete.hat is Ischemia? Ischemia is the medical term for an inadequate blood supply to a specific area of the body. This results in a reduced oxygen supply as blood has difficulty in reaching the target tissues or organs.