What Is the Costovertebral Angle?

The costovertebral angle, sometimes referred to as CVA, is the space created by the downward lateral slope of the last rib and the beginning of the lumbar vertebrae or back bones of the spine. The lumbar bones are the portion of the spinal bones between the diaphragm, a dome-shaped breathing muscle separating the trunk from the abdomen, and the sacrum or pelvis. This opening shapes or carves out an area over the kidneys.

The area created by the costovertebral angle offers protection of the kidneys. However, experiencing sensitivity or tenderness in this region may be a sign of some sort of problem with the kidneys or the surrounding structures. Common kidney issues include pyelonephritis, an infection in the urinary tract which travels into the kidney causing abdominal pain, fever, painful urination and pain that radiates into the back in addition to CVA tenderness. The abrupt appearance of CVA sensitivity may suggest a sudden swelling or distention of the renal capsule.

The renal capsule is a thick covering surrounding the kidneys consisting of several layers of tissue including adipose or fat tissue. Its role is to protect the kidneys from harm. When this casing becomes inflamed, pain symptoms may also travel around the body and extend into the umbilicus or belly button area. Pain may be extreme as the swelling pushes on the surrounding structures including the nerves. Pressure of the nerves is the main cause of pain that radiates into a different area.

When changes are experienced in voiding, such as a change in the color of urine or a change of frequency, coupled with CVA tenderness, the kidneys are the primary culprit. Additional voiding issues may include nocturia or the need to urinate during the night, and tenesmus, straining to urinate without results. A perirenal abscess, or an infection causing a pouch of fluid known as pus around the kidneys, and renal artery occlusion, a narrowing of the blood vessels providing for the kidneys, may also be the root cause of costovertebral angle tenderness.

The most common way to assess kidney issues is a technique called costovertebral angle percussion. This procedure is performed by placing one hand flat over the costovertebral angle and striking it with the side of the closed fist of the opposite hand. The force of the hit should be mild to moderate as striking this area with too much force can result in bruising or irritation to the underlying structures, including the kidneys. If pain is experienced there is a good chance a problem with the kidneys is present.