Several important organs sit against or within the back of your body, protected by your spine, ribs, and layers of muscle. The most prominent are the kidneys, adrenal glands, and spinal cord, all of which are true posterior organs. But the back is also where you feel problems from organs that sit deeper in the chest and abdomen, making it useful to understand both what lives there and what refers pain there.
The Kidneys
Your two kidneys are the largest organs located in the back of your body. Each one is roughly the size of your fist and sits behind the abdominal cavity, against the muscles of your lower back. They extend from roughly the level of your lowest rib down to your mid-lower back, spanning the vertebrae from T12 to L3. The right kidney typically sits slightly lower than the left because the liver takes up space above it.
Because the kidneys are so close to the surface of your back, kidney problems often feel like back pain rather than abdominal pain. A kidney infection usually causes a deep ache on one side of your lower back, sometimes with fever and painful urination. Kidney stones tend to produce sharp, intense pain that radiates from the flank around toward the groin. If you’re experiencing unexplained one-sided lower back pain, the kidneys are one of the first organs worth considering.
The Adrenal Glands
Sitting on top of each kidney like small caps, the adrenal glands are triangular organs that produce hormones controlling stress response, blood pressure, metabolism, and immune function. Each gland is wrapped in a layer of fat that cushions and protects it. Despite their small size, they are critical: the outer layer produces hormones that regulate salt and water balance, while the inner core releases adrenaline during stress or danger.
Adrenal problems rarely cause noticeable back pain on their own, but tumors or severe adrenal conditions can occasionally produce flank discomfort alongside hormonal symptoms like unexplained weight changes, fatigue, or blood pressure swings.
The Spinal Cord
The spinal cord is the only major organ that runs the entire length of your back. It’s a cylinder-shaped tube of nerve tissue that extends from the base of your brain down through your spine to your lower back, acting as the main communication highway between your brain and the rest of your body.
The cord itself is surprisingly well protected. The bony vertebral column surrounds it completely. Inside that, three layers of tissue called meninges provide additional shielding. The outermost layer (the dura mater) is a tough protective sheath. A middle layer and an innermost layer sit beneath it, with cerebrospinal fluid filling the space between them to cushion the cord against impact. This layered system means the spinal cord can withstand significant daily movement and minor trauma, though sudden, severe injuries can still cause lasting damage.
The Lungs and Pleura
The backs of both lungs extend surprisingly far toward your spine. Your lower lung lobes reach down to about the level of your tenth rib in the back, which is lower than most people expect. The pleura, a thin membrane lining the lungs and chest wall, covers this entire area. Conditions like pneumonia, pleurisy (inflammation of the pleura), or a collapsed lung can all produce sharp or aching upper-to-mid back pain, sometimes worsening with deep breaths.
The Pancreas and Aorta
The pancreas sits deep in the upper abdomen but is positioned against the back wall of the abdominal cavity, directly in front of the spine at roughly the level of the first and second lumbar vertebrae. Pancreatitis often causes pain that bores straight through to the mid-back, and some people find the pain improves when leaning forward.
The aorta, your body’s largest artery, also runs along the spine through both the chest and abdomen. An abdominal aortic aneurysm (a dangerous bulge in the artery wall) can cause sudden, severe back pain, sometimes described as a deep, pulsating ache. This is a medical emergency.
Organs That Refer Pain to the Back
Several organs that don’t physically sit in your back can still make it hurt. This happens through referred pain, where nerves from an internal organ share pathways with nerves from back muscles and skin, causing your brain to misinterpret where the signal is coming from.
- Gallbladder: Gallstones commonly cause pain between the shoulder blades or in the right upper back, often after eating fatty meals.
- Heart: A heart attack can produce pain in the upper back, left shoulder, or between the shoulder blades, sometimes without any chest pain at all. This is more common in women.
- Spleen: A ruptured spleen can cause sharp pain between the shoulder blades, known as Kehr’s sign, often following abdominal trauma.
- Colon: Problems in the colon, including severe constipation, diverticulitis, or colon inflammation, can produce lower back or flank pain.
The key distinction is timing and context. Muscular back pain usually changes with movement or position. Organ-related back pain tends to be constant, may come with other symptoms like nausea, fever, or breathing difficulty, and often doesn’t improve with stretching or rest. Back or shoulder pain combined with trouble breathing, dizziness, or chest tightness warrants immediate medical attention, as these can signal a heart attack or another serious cardiovascular issue.