You have two kidneys, one on each side of your spine, tucked against your back just above your waist. They sit behind your abdominal organs, roughly between the bottom of your ribcage and the top of your hip area. The right kidney is slightly lower than the left because the liver, which sits above it, pushes it down.
Exact Location of Each Kidney
Both kidneys are positioned in what’s called the retroperitoneal space, a compartment behind the digestive organs but still inside the abdominal cavity. If you place your hands on your back just below the lowest ribs on either side of your spine, you’re covering the general area where your kidneys sit. They span from roughly the level of your lowest rib down to about your third lumbar vertebra, which is a few inches below the bottom of your ribcage.
The left kidney is typically a little higher than the right. This asymmetry exists because your liver takes up considerable space on the right side of your abdomen, nudging the right kidney downward. The size difference is slight too: the left kidney averages about 11.2 cm long, while the right averages 10.9 cm, based on ultrasound measurements in adults.
Both kidneys are partially shielded by the lower ribs, which offer some protection to their upper portions. Despite sitting fairly deep in the body, the lower tip of the right kidney can sometimes be felt during a physical exam in thin individuals. The left kidney is rarely palpable. If a doctor can easily feel either kidney through your abdomen, that’s generally considered abnormal and suggests the organ may be enlarged.
How to Locate Kidney Pain
Kidney pain is often felt in the back, not the front. The key landmark is the costovertebral angle, the point on each side of your back where your lowest rib meets your spine. It forms roughly a 90-degree angle, and your kidneys sit just behind it. When a doctor checks for kidney problems, they may place a hand flat over this spot and tap it with their other fist. If that produces a deep ache or sharp tenderness, it suggests the kidney on that side is inflamed or irritated.
What makes kidney pain distinctive is where it travels. It typically starts as a deep ache in your side or back, then can radiate forward into your lower abdomen or down into your groin. This pattern of spreading pain is especially common with kidney stones, which cause pain that shifts as the stone moves through the urinary tract. The pain tends to feel deeper than a muscle strain, and it doesn’t usually change when you shift position or press on the area.
Kidney Pain vs. Back Pain
Because kidneys sit against the back muscles, it’s easy to confuse kidney pain with a pulled muscle or spinal issue. A few differences help distinguish them. Muscular back pain usually worsens with movement, bending, or twisting, and you can often pinpoint a tender spot by pressing on it. Kidney pain tends to be constant or come in waves, sits higher up (closer to your ribs than your belt line), and doesn’t respond to changes in posture.
Kidney pain also tends to come with other symptoms that back pain doesn’t. Fever, painful urination, blood in the urine, nausea, or urine that looks cloudy or smells unusual all point toward a kidney issue rather than a musculoskeletal one. Pain from a kidney infection often affects just one side, which can help identify which kidney is involved.
Why It Matters Which Side Hurts
Because you have a kidney on each side, the location of your pain gives your doctor immediate diagnostic information. Right-sided flank pain can overlap with conditions involving the liver, gallbladder, or appendix, all of which sit on the right. Left-sided flank pain is less likely to be confused with other organ problems, making kidney issues easier to identify on that side.
Each kidney connects to the bladder through its own tube called the ureter, and each receives blood through its own artery branching directly off the body’s main blood vessel. These connections enter the kidney at a spot on its inner curve called the hilum, which faces toward the spine. Problems like kidney stones or blockages affect one side at a time in most cases, so knowing your anatomy helps you communicate more clearly with a healthcare provider about what you’re feeling and where.
Pain that wraps from your back around to your groin on one side, especially if it comes in intense waves, is one of the most recognizable patterns of a kidney stone. Pain that’s duller and steady, combined with fever, is more characteristic of an infection. In either case, the side of the pain corresponds to the kidney involved.