Kylkialueen

Kylkialueen refers to the flank region, the lateral part of the torso between the lower rib cage and the pelvis. It encompasses the lateral abdominal wall and the adjacent back region, extending on both the left and right sides of the body. In everyday and clinical language, the flank is a key anatomic landmark for assessing pain, tenderness, or injury in the torso.

Anatomically, the flank contains components of the lateral abdominal wall, primarily the external oblique, internal oblique, and transversus abdominis muscles, as well as overlying fascia and fat. Posteriorly, muscles of the back such as latissimus dorsi, erector spinae, and quadratus lumborum contribute to the flank’s structure. The area also serves as a corridor for neurovascular structures, including the intercostal nerves and the iliohypogastric and ilioinguinal nerves, which provide sensory and motor innervation to the abdominal wall. The kidneys are located in the posterior flank region, retroperitoneally, roughly from the T12 to L3 vertebrae, partially protected by the lower ribs.

Clinically, flank pain is a common symptom with a broad differential that includes musculoskeletal strain, renal colic from stones, pyelonephritis, and referred pain from abdominal organs. Surgical approaches and incisions may target the flank region for renal or retroperitoneal procedures. The term kylkialueen is the genitive form used in Finnish to denote “of the flank region” in medical and anatomical contexts.