What is the medical term for the lower back or loin?

The medical term for the lower back or loin is "lumb/o." This root word is derived from the Latin term "lumbus," which specifically refers to the loin or the lower part of the back. In medical terminology, "lumb/o" is often used to describe conditions, procedures, or anatomical references related to this area, such as lumbago (lower back pain) or lumbar spine (the portion of the spine in the lower back).

The other terms relate to different anatomical areas or concepts. For instance, "pelv/o" pertains to the pelvis, which is the bony structure at the lower end of the spine, while "physi/o" relates to physiological processes or functions of the body. Similarly, "pleur/o" is associated with the pleura, the membranes surrounding the lungs. Therefore, when referring specifically to the lower back, "lumb/o" is the precise and correct choice.