The renal pelvis or pelvis of the kidney is the funnel-like dilated part of the
ureter
The ureters are tubes composed of smooth muscle that transport urine from the kidneys to the urinary bladder. In an adult human, the ureters typically measure 20 to 30 centimeters in length and about 3 to 4 millimeters in diameter. They are lin ...
in the
kidney
In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...
. It is formed by the convergence of the
major calyces, acting as a funnel for urine flowing from the major calyces to the ureter. It has a
mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...
and is covered with
transitional epithelium and an underlying
lamina propria of loose-to-dense
connective tissue
Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesod ...
.
The renal pelvis is situated within the
renal sinus
The renal sinus is a cavity within the kidney which is occupied by the renal pelvis, renal calyces, blood vessels, nerves and fat. The renal hilum extends into a large cavity within the kidney occupied by the renal vessels, minor renal calyces, ...
alongside the other structures of the renal sinus.
Clinical significance
The renal pelvis is the location of several kinds of
kidney cancer and is affected by infection in
pyelonephritis
Pyelonephritis is inflammation of the kidney, typically due to a bacterial infection. Symptoms most often include fever and flank tenderness. Other symptoms may include nausea, burning with urination, and frequent urination. Complications ...
. A large "
staghorn" kidney stone may block all or part of the renal pelvis.
The size of the renal pelvis plays a major role in the
grading of hydronephrosis. Normally, the anteroposterior diameter of the renal pelvis is less than 4 mm in
fetus
A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...
es up to 32 weeks of
gestational age and 7 mm afterwards.
[Page 189]
in: In adults, 13% of the normal population have a transverse pelvic diameter of over 10 mm.
Etymology and pronunciation
Like the
bony pelvis, the renal pelvis () gets its English name via
Neo-Latin
Neo-LatinSidwell, Keith ''Classical Latin-Medieval Latin-Neo Latin'' in ; others, throughout. (also known as New Latin and Modern Latin) is the style of written Latin used in original literary, scholarly, and scientific works, first in Italy d ...
from the older
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
word ''
pelvis
The pelvis (: pelves or pelvises) is the lower part of an Anatomy, anatomical Trunk (anatomy), trunk, between the human abdomen, abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also c ...
'', "basin", as in "
wash basin".
In both cases the name reflects the shape of the structure, and in the case of the renal pelvis, it also reflects the function. The name reflects that each renal pelvis collects
urine
Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...
from the
calyces and funnels it into the
ureter
The ureters are tubes composed of smooth muscle that transport urine from the kidneys to the urinary bladder. In an adult human, the ureters typically measure 20 to 30 centimeters in length and about 3 to 4 millimeters in diameter. They are lin ...
like a wash basin collects
water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
and funnels it into a
drain pipe. The renal pelvis is occasionally called the pyelum (from Greek πύελος ''pýelos'', "trough", ‘anything hollow’), and the
combining form ''
pyelo-'' denotes the renal pelvis (''pyelo-'' is not to be confused with ''
pyo-''). The words ''
infundibulum'' and ''
choana'' are other words for funnel-shaped cavities (which medical English got from the Latin and Greek words for "funnel", respectively), and the renal pelvis is sometimes called the renal infundibulum. The form ''*renal choana''
is logical but is not used.
Additional images
File:Gray1118.png, Depiction of the developing renal pelvis.
File:Slide17iii.JPG, Cutaway section of a preserved human kidney
See also
*
Renal sinus
The renal sinus is a cavity within the kidney which is occupied by the renal pelvis, renal calyces, blood vessels, nerves and fat. The renal hilum extends into a large cavity within the kidney occupied by the renal vessels, minor renal calyces, ...
*
Pyelectasis, the dilation of the renal pelvis
References
External links
* —"Section of the kidney, anterior view."
*
* —"Mammal, renal pelvis (Gross, Medium)"
* —"Mammal, renal pelvis (LM, Medium)"
{{Authority control
Kidney anatomy