A projecting ridge or fin on the bottom of the hull of a boat or ship that improves directional control and is often weighted for added stability. 2. The principal structural member of an aircraft, resembling a ship's keel in shape and function.
The outer, reddish region, next to the capsule, is the renal cortex. This surrounds a darker reddish-brown region called the renal medulla. The renal medulla consists of a series of renal pyramids, which appear striated because they contain straight tubular structures and blood vessels.
The lateral surface is convex. The medial surface is concave, deeply grooved (renal sinus) and forms the renal hilum. The ureter/renal pelvis, renal artery, renal vein, lymphatic vessels and nerves enter or exit through the renal hilum the kidney.he kidneys are located in the retroperitoneum, right and left of the spine and below the diaphragm. Normal position: 1  Left kidney: from the 11th rib to third lumbar vertebra. 2  Right kidney: slightly lower position, 12th rib to the lower part of the third lumbar vertebra.