The ureters are tubes made of smooth muscle that propel
urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.
Cellular ...
from the
kidney
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...
s to the
urinary bladder
The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine ente ...
. In a human adult, the ureters are usually long and around in diameter. The ureter is lined by
urothelial
Transitional epithelium also known as urothelium is a type of stratified epithelium. Transitional epithelium is a type of tissue that changes shape in response to stretching (stretchable epithelium). The transitional epithelium usually appears ...
cells, a type of
transitional epithelium
Transitional epithelium also known as urothelium is a type of stratified epithelium. Transitional epithelium is a type of tissue that changes shape in response to stretching (stretchable epithelium). The transitional epithelium usually appears ...
, and has an additional smooth muscle layer that assists with
peristalsis
Peristalsis ( , ) is a radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, whic ...
in its lowest third.
The ureters can be affected by a number of diseases, including
urinary tract infections
A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidne ...
and
kidney stone
Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...
. is when a ureter is narrowed, due to for example chronic inflammation.
Congenital abnormalities
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can r ...
that affect the ureters can include the development of two ureters on the same side or abnormally placed ureters. Additionally, reflux of urine from the bladder back up the ureters is a condition commonly seen in children.
The ureters have been identified for at least two thousand years, with the word "ureter" stemming from the stem relating to
urinating
Urination, also known as micturition, is the release of urine from the urinary bladder through the urethra to the outside of the body. It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, ...
and seen in written records since at least the time of
Hippocrates
Hippocrates of Kos (; grc-gre, Ἱπποκράτης ὁ Κῷος, Hippokrátēs ho Kôios; ), also known as Hippocrates II, was a Greek physician of the classical period who is considered one of the most outstanding figures in the history o ...
. It is, however, only since the 1500s that the term "ureter" has been consistently used to refer to the modern structure, and only since the development of medical imaging in the 1900s that techniques such as
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
have been able to view the ureters. The ureters are also seen from the inside using a flexible camera, called
ureteroscopy
Ureteroscopy is an examination of the upper urinary tract, usually performed with a ureteroscope that is passed through the urethra and the bladder, and then directly into the ureter. The procedure is useful in the diagnosis and treatment of diso ...
, which was first described in 1964.
Structure
The ureters are tubular structures, approximately in adults, that pass from the pelvis of each kidney into the bladder. From the renal pelvis, they descend on top of the
psoas major
The psoas major ( or ; from grc, ψόᾱ, psóā, muscles of the loins) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the iliop ...
muscle to reach the
brim of the pelvis
The pelvic brim is the edge of the pelvic inlet. It is an approximately Mickey Mouse head-shaped line passing through the prominence of the sacrum, the Arcuate line (ilium), arcuate and pectineal line (pubis), pectineal lines, and the upper margin ...
. Here, they cross in front of the common iliac arteries. They then pass down along the sides of the pelvis and finally curve forward and enter the bladder from its left and right sides at the back of the bladder. The ureters are in diameter and surrounded by a layer of smooth muscle for near their ends just before they enter the bladder.
The ureters enter the bladder from its back surface, traveling before opening into the bladder at an angle on its outer back surface at the slit-like ''ureteric orifices''. This location is also called the vesicoureteric junction. In the contracted bladder, they are about apart and about the same distance from the
internal urethral orifice
The internal urethral orifice is the opening of the urinary bladder into the urethra. It is placed at the apex of the trigonum vesicae, in the most dependent part of the bladder, and is usually somewhat crescent-shaped; the mucous membrane immedi ...
; in the distended bladder, these measurements may be increased to about .
A number of structures pass by, above, and around the ureters on their path down from the kidneys to the bladder. In its upper part, the ureter travels on the
psoas major muscle
The psoas major ( or ; from grc, ψόᾱ, psóā, muscles of the loins) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the il ...
and sits just behind the
peritoneum
The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of meso ...
. As it passes down the muscle, it travels over the
genitofemoral nerve
The genitofemoral nerve refers to a nerve that is found in the abdomen. Its branches, the genital branch and femoral branch supply sensation to the upper anterior thigh, as well as the skin of the anterior scrotum in males and mons pubis in fema ...
. The
inferior vena cava
The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of th ...
and the abdominal aorta sit to the midline of the right and left ureters, respectively. In the lower part of the abdomen, the right ureter sits behind the lower mesentery and the
terminal ileum
The ileum () is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine m ...
, and the left ureter sits behind the
jejunum
The jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialised for the absorption by enterocytes of small nutrient molecules which have been previou ...
and the sigmoid colon. As the ureters enter the pelvis, they are surrounded by connective tissue, and travel backward and outward, passing in front of the
internal iliac arteries
The internal iliac artery (formerly known as the hypogastric artery) is the main artery of the pelvis.
Structure
The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial compart ...
middle rectal arteries
The middle rectal artery is an artery in the pelvis that supplies blood to the rectum.
Structure
The middle rectal artery usually arises from the internal iliac artery. It is distributed to the rectum above the pectinate line. It Anastomosis, an ...
. From here, in males, they cross under the vas deferens and in front of the
seminal vesicles
The seminal vesicles (also called vesicular glands, or seminal glands) are a pair of two convoluted tubular glands that lie behind the urinary bladder of some male mammals. They secrete fluid that partly composes the semen.
The vesicles are 5 ...
to enter the bladder near the trigone. In females, the ureters pass behind the
ovaries
The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...
and then travel in the lower midline section of the
broad ligament of the uterus
The broad ligament of the uterus is the wide fold of peritoneum that connects the sides of the uterus to the walls and floor of the pelvis.
Structure
Subdivisions
Contents
The contents of the broad ligament include the following:
* Reprodu ...
. For a short part, the
uterine arteries
The uterine artery is an artery that supplies blood to the uterus in females.
Structure
The uterine artery usually arises from the anterior division of the internal iliac artery. It travels to the uterus, crossing the ureter anteriorly, to the ute ...
travel on top for a short () period. They then pass by the cervix, traveling inward towards the bladder.
Blood and lymphatic supply
The arteries which supply the ureter vary along its course. The upper third of the ureter, closest to the kidney, is supplied by the
renal arteries
The renal arteries are paired arteries that supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle.
The renal arteries carry a large portion of total blood flow to the kidneys. Up to a ...
testicular artery
The testicular artery (the male gonadal artery, also called the internal spermatic arteries in older texts) is a branch of the abdominal aorta that supplies blood to the testis. It is a paired artery, with one for each of the testes.
It is the ...
in men and the
ovarian artery
The ovarian artery is an artery that supplies oxygenated blood to the ovary in females. It arises from the abdominal aorta below the renal artery. It can be found within the suspensory ligament of the ovary, anterior to the ovarian vein and uret ...
in women. The lower third of the ureter, closest to the bladder, is supplied by branches from the
internal iliac arteries
The internal iliac artery (formerly known as the hypogastric artery) is the main artery of the pelvis.
Structure
The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial compart ...
inferior vesical arteries
The inferior vesical artery (or inferior vesicle artery) is an artery of the pelvis which arises from the internal iliac artery and supplies parts of the urinary bladder as well as other structures of the urinary system and structures of the male r ...
. The arterial supply can be variable, with arteries that contribute include the
middle rectal artery
The middle rectal artery is an artery in the pelvis that supplies blood to the rectum.
Structure
The middle rectal artery usually arises from the internal iliac artery. It is distributed to the rectum above the pectinate line. It anastomoses wit ...
, branches directly from the aorta, and, in women, the uterine and vaginal arteries.
The
arteries
An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...
that supply the ureters end in a network of vessels within the
adventitia
The adventitia () is the outer layer of fibrous connective tissue surrounding an organ.
The outer layer of connective tissue that surrounds an artery, or vein – the tunica externa, is also called the ''tunica adventitia''.
To some degree, its ...
of the ureters. There are many connections () between the arteries of the ureter, particularly in the adventitia, which means damage to a single vessel does not compromise the blood supply of the ureter. Venous drainage mostly parallels that of the arterial supply; that is, it begins as a network of smaller veins in the adventitia; with the renal veins draining the upper ureters, and the vesicular and gonadal veins draining the lower ureters.
Lymphatic drainage depends on the position of lymphatic vessels in the ureter.
Lymph
Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues ...
collects in submucosal, intramuscular and adventitial
lymphatic vessels
The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vessel ...
. Those vessels closer to the kidney drain into renal collecting vessels, and from here into the lateral aortic nodes near the gonadal vessels. The middle part of the ureter drains into the right paracaval and interaortocaval nodes on the right, and the left paraaortic nodes on the left. In the lower ureter, lymph may drain into the common iliac lymph nodes, or lower down in the pelvis to the common,
external
External may refer to:
* External (mathematics), a concept in abstract algebra
* Externality
In economics, an externality or external cost is an indirect cost or benefit to an uninvolved third party that arises as an effect of another party' ...
, or
internal iliac lymph nodes
The internal iliac lymph nodes (or hypogastric) surround the internal iliac artery and its branches (the ''hypogastric vessels''), and receive the lymphatics corresponding to the distribution of the branches of it, i. e., they receive lymphatics fr ...
.
Nerve supply
The ureters are richly supplied by nerves that form a network () of nerves, the
ureteric plexus
The ureteric plexus is a nerve plexus covering and innervating the ureter. The plexus can be graduated into three parts, as the ureter itself can be divided: In the upper part of the ureter, the plexus gets its nerve fibers mainly from the renal p ...
that lies in the adventitia of the ureters. This plexus is formed from a number of
nerve roots A nerve root (Latin: ''radix nervi'') is the initial segment of a nerve leaving the central nervous system. Nerve roots can be classified as:
*Cranial nerve roots: the initial or proximal segment of one of the twelve pairs of cranial nerves leaving ...
directly (T9-12, L1, and S2-4), as well as branches from other nerve plexuses and nerves; specifically, the upper third of the ureter receives nerve branches from the
renal plexus
The renal plexus is a complex network of nerves formed by filaments from the celiac ganglia and plexus, aorticorenal ganglia, lower thoracic splanchnic nerves and first lumbar splanchnic nerve and aortic plexus.
The nerves from these sources ...
and aortic plexus, the middle part receives branches from the upper hypogastric plexus and nerve, and the lower ureter receives branches from the lower hypogastric plexus and nerve. The plexus is in the adventitia. These nerves travel in individual bundles and along small blood vessels to form the ureteric plexus. Sensation supplied is sparse close to the kidneys and increases closer to the bladder.
Sensation to the ureters is provided by nerves that come from T11 - L2 segments of the
spinal cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...
. When pain is caused, for example by spasm of the ureters or by a stone, the pain may be referred to the
dermatome Dermatome may refer to:
* Dermatome (anatomy), an area of skin that is supplied by a single pair of dorsal roots
* Dermatome (embryology), the portion of the embryonic paraxial mesoderm, the somite, which gives rise to dermis
* Dermatome (instrument ...
s of T11 - L2, namely the back and sides of the abdomen, the scrotum (males) or labia majora (females) and upper part of the front of the thigh.
Microanatomy
The ureter is lined by
urothelium
Transitional epithelium also known as urothelium is a type of stratified epithelium. Transitional epithelium is a type of tissue that changes shape in response to stretching (stretchable epithelium). The transitional epithelium usually appears ...
, a type of
transitional epithelium
Transitional epithelium also known as urothelium is a type of stratified epithelium. Transitional epithelium is a type of tissue that changes shape in response to stretching (stretchable epithelium). The transitional epithelium usually appears ...
that is capable of responding to stretches in the ureters. The transitional epithelium may appear as a layer of column-shaped cells when relaxed, and of flatter cells when distended. Below the epithelium sits the lamina propria. The lamina propria is made up of loose connective tissue with many elastic fibers interspersed with blood vessels, veins and lymphatics. The ureter is surrounded by two muscular layers, an inner longitudinal layer of muscle, and an outer circular or spiral layer of muscle. The lower third of the ureter has a third muscular layer. Beyond these layers sits an
adventitia
The adventitia () is the outer layer of fibrous connective tissue surrounding an organ.
The outer layer of connective tissue that surrounds an artery, or vein – the tunica externa, is also called the ''tunica adventitia''.
To some degree, its ...
containing blood vessels, lymphatic vessels, and veins.
Development
The ureters develop from the
ureteric bud
The ureteric bud, also known as the metanephric diverticulum, is a protrusion from the mesonephric duct during the development of the urinary and reproductive organs. It later develops into a conduit for urine drainage from the kidneys, which, in ...
s, which are outpouchings from the
mesonephric duct
The mesonephric duct (also known as the Wolffian duct, archinephric duct, Leydig's duct or nephric duct) is a paired organ that forms during the embryonic development of humans and other mammals and gives rise to male reproductive organs.
Stru ...
. This is a duct, derived from mesoderm, found in the early
embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
. Over time, the buds elongate, moving into surrounding mesodermal tissue, dilate, and divide into left and right ureters. Eventually, successive divisions from these buds form not only the ureters, but also the pelvis, major and minor calyces, and collecting ducts of the kidneys.
The mesonephric duct is connected with the cloaca, which over the course of development splits into a
urogenital sinus
The urogenital sinus is a part of the human body only present in the development of the urinary and reproductive organs. It is the ventral part of the cloaca, formed after the cloaca separates from the anal canal during the fourth to seventh w ...
and the
anorectal canal The anorectal canal is an embryonic structure in humans that develops from the posterior portion of the cloaca, after it is divided by the urorectal septum in the 6th week of embryonic development. The anterior portion becomes the urogenital sinu ...
. The urinary bladder forms from the urogenital sinus. Over time, as the bladder enlarges, it absorbs the surrounding parts of the primitive ureters. Finally, the entry points of the ureters into the bladder move upwards, owing to the upward migration of the kidneys in the developing embryo.
Function
The ureters are a component of the
urinary system
The urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, c ...
.
Urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.
Cellular ...
, produced by the kidneys, travels along the ureters to the bladder. It does this through regular contractions called
peristalsis
Peristalsis ( , ) is a radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, whic ...
Ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
showing a jet of urine entering the bladder (large black section) through the ureter.
Clinical significance
Ureteral stones
A
kidney stone
Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...
can move from the
kidney
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...
and become lodged inside the ureter, which can block the flow of urine, as well as cause a sharp
cramp
A cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the aff ...
in the back, side, or lower
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
. Pain often comes in waves lasting up to two hours, then subsides, called
renal colic
Renal colic is a type of abdominal pain commonly caused by obstruction of ureter from dislodged kidney stones. The most frequent site of obstruction is the vesico-ureteric junction (VUJ), the narrowest point of the upper urinary tract. Acute ob ...
. The affected kidney could then develop
hydronephrosis
Hydronephrosis describes hydrostatic dilation of the renal pelvis and calyces as a result of obstruction to urine flow downstream. Alternatively, hydroureter describes the dilation of the ureter, and hydronephroureter describes the dilation of t ...
, should a part of the kidney become
swollen
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels tight, the area ma ...
due to blocked flow of urine. It is classically described that there are three sites in the ureter where a kidney stone will commonly become stuck:
where the ureter meets the renal pelvis; where the iliac blood vessels cross the ureters; and where the ureters enter the urinary bladder, however a retrospective
case study
A case study is an in-depth, detailed examination of a particular case (or cases) within a real-world context. For example, case studies in medicine may focus on an individual patient or ailment; case studies in business might cover a particular fi ...
, which is a
primary source
In the study of history as an academic discipline, a primary source (also called an original source) is an artifact, document, diary, manuscript, autobiography, recording, or any other source of information that was created at the time under ...
, of where stones lodged based on medical imaging did not show many stones at the place where the iliac blood vessels cross.
Most stones are compounds containing
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
calcium phosphate
The term calcium phosphate refers to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are whi ...
. The first recommended investigation is a CT scan of the abdomen because it can detect almost all stones. Management includes
analgesia
Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professional ...
lithotripsy
Lithotripsy is a non-invasive procedure involving the physical destruction of hardened masses like kidney stones, bezoars or gallstones. The term is derived from the Greek words meaning "breaking (or pulverizing) stones" ( litho- + τρίψω r ...
, and those with complications such as hydronephrosis or infection may require surgery to remove.
Reflux
Vesicoureteral reflux
Vesicoureteral reflux (VUR), also known as vesicoureteric reflux, is a condition in which urine flows retrograde, or backward, from the bladder into one or both ureters and then to the renal calyx or kidneys. Urine normally travels in one directio ...
refers to the reflux of fluid from the bladder into the ureters. This condition can be associated with
urinary tract infection
A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidne ...
s, particularly in children, and is present in up to 28–36% of children to some degree. A number of forms of medical imaging are available for diagnosis of the condition, with modalities including doppler
urinary tract ultrasound
Ultrasound of the urinary tract involves the use of an ultrasound probe to image parts of the urinary tract. The urinary tract is the path that urine follows after it is formed within the kidneys, and involves a left and right ureter, the bladder, ...
,
MAG 3 Mag, MAG or mags may refer to:
Arts, entertainment and media
* ''MAG'' (video game), 2010
* ''Mag'' (Slovenian magazine), 1995–2010
* '' The Mag'', a British music magazine
Businesses and organisations
* MacKenzie Art Gallery, in Regina, Sask ...
nuclear medicine scan
Nuclear may refer to:
Physics
Relating to the nucleus of the atom:
* Nuclear engineering
*Nuclear physics
*Nuclear power
*Nuclear reactor
*Nuclear weapon
*Nuclear medicine
*Radiation therapy
*Nuclear warfare
Mathematics
*Nuclear space
*Nuclear ...
ing, and a micturition urethrocystogram. Factors that affect which of these are selected depends if a child is able to receive a
urinary catheter
In urinary catheterization a latex, polyurethane, or silicone tube known as a urinary catheter is inserted into the bladder through the urethra to allow urine to drain from the bladder for collection. It may also be used to inject liquids used ...
, and whether a child is toilet trained. Whether these investigations are performed at the first time a child has an illness, or later and depending on other factors (such as if the causal bacteria is '' E. coli'') differ between US, EU and UK guidelines.
Management is also variable, with differences between international guidelines on issues such as whether
prophylactic antibiotic
Preventive healthcare, or prophylaxis, consists of measures taken for the purposes of disease prevention.Hugh R. Leavell and E. Gurney Clark as "the science and art of preventing disease, prolonging life, and promoting physical and mental hea ...
s should be used, and whether surgery is recommended. One reason is most instances of vesicoureteral reflux improve by themselves. If surgery is considered, it generally involves reattaching the ureters to a different spot on the bladder, and extending the part of the ureter that it is within the wall of the bladder, with the most common surgical option being Cohen's cross-trigonal reimplantation.
Anatomical and surgical abnormalities
Blockage, or obstruction of the ureter can occur, as a result of narrowing within the ureter, or compression or fibrosis of structures around the ureter. Narrowing can result of ureteric stones, masses associated with cancer, and other lesions such as endometriosis
tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...
constipation
Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...
and
retroperitoneal fibrosis
Retroperitoneal fibrosis or Ormond's disease is a disease featuring the proliferation of fibrous tissue in the retroperitoneum, the compartment of the body containing the kidneys, aorta, renal tract, and various other structures. It may present wi ...
can also compress them. Some
congenital abnormalities
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can r ...
can also result in narrowing or the ureters. Congenital disorders of the ureter and
urinary tract
The urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, c ...
affect 10% of infants. These include partial or total duplication of the ureter (a duplex ureter), or the formation of a second irregularly placed () ureter; or where the junction with the bladder is malformed or a
ureterocoele
A ureterocele is a congenital abnormality found in the ureter. In this condition the distal ureter balloons at its opening into the bladder, forming a sac-like pouch. It is most often associated with a duplicated collection system, where two uret ...
develops (usually in that location). If the ureters have been resited as a result of surgery, for example due to a
kidney transplant
Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantati ...
or due to past surgery for vesicoureteric reflux, that site may also become narrowed.
A narrowed ureter may lead to ureteric enlargement () and cause swelling of the kidneys (
hydronephrosis
Hydronephrosis describes hydrostatic dilation of the renal pelvis and calyces as a result of obstruction to urine flow downstream. Alternatively, hydroureter describes the dilation of the ureter, and hydronephroureter describes the dilation of t ...
). Associated symptoms may include recurrent infections, pain or
blood in the urine
Hematuria or haematuria is defined as the presence of blood or red blood cells in the urine. “Gross hematuria” occurs when urine appears red, brown, or tea-colored due to the presence of blood. Hematuria may also be subtle and only detectable w ...
; and when tested,
kidney function
Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging.
Functions of a healthy kidney include maintaining a person's fluid ...
might be seen to decrease. These are considered situations when surgery is needed. Medical imaging, including urinary tract ultrasound, CT or
nuclear medicine
Nuclear medicine or nucleology is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear imaging, in a sense, is " radiology done inside out" because it records radiation emi ...
imaging is conducted to investigate many causes. This may involve reinserting the ureters into a new place on the bladder (reimplantion), or widening of the ureter. A
ureteric stent
A ureteral stent (pronounced you-REE-ter-ul), or ureteric stent, is a thin tube inserted into the ureter to prevent or treat obstruction of the urine flow from the kidney. The length of the stents used in adult patients varies between 24 and 30&nb ...
may be inserted to relieve an obstruction. If the cause cannot be removed, a
nephrostomy
A nephrostomy is an artificial opening created between the kidney and the skin which allows for the urinary diversion directly from the upper part of the urinary system (renal pelvis).
An urostomy is a related procedure performed more distally a ...
may be required, which is the insertion of a tube connected to the renal pelvis which directly drains urine into a
stoma bag
An ostomy pouching system is a prosthetic medical device that provides a means for the collection of waste from a surgically diverted biological system ( colon, ileum, bladder) and the creation of a stoma. Pouching systems are most commonly asso ...
.
Cancer
Cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
of the ureters is known as
ureteral cancer
Ureteral cancer is cancer of the ureters, muscular tubes that propel urine from the kidneys to the urinary bladder. It is also known as ureter cancer,smoking and exposure to dyes such as
aromatic amine
In organic chemistry, an aromatic amine is an organic compound consisting of an aromatic ring attached to an amine. It is a broad class of compounds that encompasses aniline
Aniline is an organic compound with the formula C6 H5 NH2. Consi ...
s and
aldehydes
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...
. When cancer is present, the most common symptom in an affected person is blood in the urine; it may not cause symptoms, and a physical
medical examination
In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions about the patie ...
may be otherwise normal, except in late disease. Ureteral cancer is most often due to cancer of the cells lining the ureter, called
transitional cell carcinoma
Transitional cell carcinoma, also called urothelial carcinoma, is a type of cancer that typically occurs in the urinary system. It is the most common type of bladder cancer and cancer of the ureter, urethra, and urachus. It accounts for 95% of ...
, although it can more rarely occur as a squamous cell carcinoma if the type of cells lining the urethra have changed due to chronic inflammation, such as due to stones or schistosomiasis.
Investigations performed usually include collecting a sample of urine for an inspection for malignant cells under a microscope, called
cytology
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living an ...
, as well as medical imaging by a CT urogram or
ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
. If a concerning lesion is seen, a flexible camera may be inserted into the ureters, called
ureteroscopy
Ureteroscopy is an examination of the upper urinary tract, usually performed with a ureteroscope that is passed through the urethra and the bladder, and then directly into the ureter. The procedure is useful in the diagnosis and treatment of diso ...
, in order to view the lesion and take a
biopsy
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...
open surgery
Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definiti ...
to remove the affected ureter and kidney if it is involved; or, if the lesion is small, it may be removed via ureteroscopy. Prognosis can vary markedly depending on the
tumour grade
In pathology, grading is a measure of the cell appearance in tumors and other neoplasms. Some pathology grading systems apply only to malignant neoplasms (cancer); others apply also to benign neoplasms. The neoplastic grading is a measure of cell ...
, with a worse prognosis associated with an ulcerating lesion.
Injury
Injuries to the ureter can occur after penetrating abdominal injuries, and injuries at high speeds followed by an abrupt stop (such as a high speed car accident). The ureter can be injured during surgery to nearby structures. It is injured in 2 per 10,000 cases of vaginal
hysterectomies
Hysterectomy is the surgical removal of the uterus. It may also involve removal of the cervix, ovaries (oophorectomy), Fallopian tubes ( salpingectomy), and other surrounding structures.
Usually performed by a gynecologist, a hysterectomy may be ...
cardinal ligament
The cardinal ligament (or Mackenrodt's ligament, lateral cervical ligament, or transverse cervical ligament) is a major ligament of the uterus. It is located at the base of the broad ligament of the uterus. There are a pair of cardinal ligaments ...
Several forms of medical imaging exist that are used to view the ureters and urinary tract. Ultrasound may be able to show evidence of blockage because of hydronephrosis of the kidneys and renal pelvis. CT scans, including ones where
contrast media
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiop ...
is injected intravenously to better show the ureters, and with contrast to better show lesions, and to differentiate benign from malignant lesions. Dye may also be injected directly into the ureters or renal tract; an antegrade pyelogram is when contrast is injected directly into the renal pelvis, and a
retrograde pyelogram
Pyelogram (or pyelography or urography) is a form of imaging of the renal pelvis and ureter.
Types include:
* Intravenous pyelogram – In which a contrast solution is introduced through a vein into the circulatory system.
* Retrograde pyelogram ...
is where dye is injected into the urinary tract via a catheter, and flows backwards into the ureters. More invasive forms of imaging include ureteroscopy, which is the insertion of a flexible
endoscope
An endoscope is an inspection instrument composed of image sensor, optical lens, light source and mechanical device, which is used to look deep into the body by way of openings such as the mouth or anus. A typical endoscope applies several modern t ...
into the urinary tract to view the ureters. Ureteroscopy is most commonly used for medium to large-sized stones when less invasive methods of removal are not able to be used.
Other animals
All
vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s have two kidneys located behind the abdomen that produce urine, and have a way of excreting it, so that waste products within the urine can be removed from the body. The structure specifically called the ureter is present in amniotes, meaning
mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...
, birds and reptiles. These animals possess an adult kidney derived from the metanephros. The duct that connects the kidney to excrete urine in these animals is the ureter. It connects to the
urinary bladder
The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine ente ...
, from whence urine leaves via the
urethra
The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra c ...
.
History
The word "ureter" comes from the
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
stem "uro" relating to urination, and the first use of the word is seen during the era of
Hippocrates
Hippocrates of Kos (; grc-gre, Ἱπποκράτης ὁ Κῷος, Hippokrátēs ho Kôios; ), also known as Hippocrates II, was a Greek physician of the classical period who is considered one of the most outstanding figures in the history o ...
to refer to the
urethra
The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra c ...
. The anatomical structure of the ureter was noted by 40 AD. However, the terms "ureter" and "urethra" were variably used to refer to each other thereafter for more than a millennium. It was only in the 1550s that anatomists such as
Bartolomeo Eustachi
Bartolomeo Eustachi (c. 1500–1510 – 27 August 1574), also known by his Latin name of Bartholomaeus Eustachius (), was an Italian anatomist and one of the founders of the science of human anatomy.
Biography
Bartolomeo Eustachio (known as Eu ...
and
Jacques Dubois
Jacques Dubois ( Latinised as Jacobus Sylvius; 1478 – 14 January 1555) was a French anatomist. Dubois was the first to describe venous valves, although their function was later discovered by William Harvey. He was the brother of Franciscus Sy ...
began to use the terms to specifically and consistently refer to what is in modern English called the ureter and the urethra. Following this, in the 19th and 20th centuries multiple terms relating to the structures such as
ureteritis
Ureteritis is a medical condition of the ureter that involves inflammation. One form is known as "ureteritis cystica".
Eosinophilic ureteritis has been observed.
Ureteritis is often considered part of a urinary tract infection
A urinary t ...
and ureterography, were coined.
Kidney stones have been identified and recorded about as long as written historical records exist. The urinary tract including the ureters, as well as their function to drain urine from the kidneys, has been described by
Galen
Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be one ...
in the second century AD.
The first to examine the ureter through an internal approach, called ureteroscopy, rather than surgery was
Hampton Young
Hampton may refer to:
Places Australia
*Hampton bioregion, an IBRA biogeographic region in Western Australia
*Hampton, New South Wales
*Hampton, Queensland, a town in the Toowoomba Region
*Hampton, Victoria
Canada
*Hampton, New Brunswick
*Hamp ...
in 1929. This was improved on by
VF Marshall
Vf or VF may stand for:
Arts and entertainment
*''Virtua Fighter'', a series of fighting games by Sega
* Variable fighter, in the ''Macross'' manga series
Businesses and organizations
* VF Corporation, a clothing company
* Valuair, an airline ba ...
who is the first published use of a flexible endoscope based on fiber optics, which occurred in 1964. The insertion of a drainage tube into the renal pelvis, bypassing the ureters and urinary tract, called nephrostomy, was first described in 1941. Such an approach differed greatly from the open surgical approaches within the urinary system employed during the preceding two millennia.
The first
radiological imaging
Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to rev ...
of the ureters first occurred via
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
s, although this was made more difficult by the thick abdomen, which the low power of the original X-rays was not able to penetrate enough to produce clear images. More useful images were able to be produced when
Edwin Hurry Fenwick
Edwin Hurry Fenwick (1856–1944), British urologist, early adopter of cystoscopic and x-ray technologies. It was largely through the efforts of Fenwick that urology was shaped into a specialty in Great Britain, recognized by the Royal Society of ...
in 1908 pioneered the use of tubes covered in material visible to X-rays inserted into the ureters, and in the early 20th century when contrasts were injected externally into the urinary tract (retrograde pyelograms). Unfortunately, much of the earlier retrograde pyelograms were complicated by significant damage to the kidneys as a result of contrast based on
silver
Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...
or
sodium iodide
Sodium iodide (chemical formula NaI) is an ionic compound formed from the chemical reaction of sodium metal and iodine. Under standard conditions, it is a white, water-soluble solid comprising a 1:1 mix of sodium cations (Na+) and iodide anions ...
. Hryntshalk in 1929 pioneered the development of the
intravenous urogram
Pyelogram (or pyelography or urography) is a form of imaging of the renal pelvis and ureter.
Types include:
* Intravenous pyelogram – In which a contrast solution is introduced through a vein into the circulatory system.
* Retrograde pyelogram ...
, in which contrast is injected into a vein and highlights the kidney and, when excreted, the urinary tract. Things improved with the development by
Moses Swick
Moses hbo, מֹשֶׁה, Mōše; also known as Moshe or Moshe Rabbeinu (Mishnaic Hebrew: מֹשֶׁה רַבֵּינוּ, ); syr, ܡܘܫܐ, Mūše; ar, موسى, Mūsā; grc, Mωϋσῆς, Mōÿsēs () is considered the most important pro ...
and
Leopold Lichtwitz Leopold Lichtwitz (9 December 1876 in Ohlau – 16 March 1943 in New Rochelle, New York) was a German-American internist.
He studied medicine in several German universities, receiving his doctorate in 1901 from the University of Leipzig. In 1 ...
in the late 1920s of relatively nontoxic contrast media, with controversy surrounding publication as to who was the primary discoverer. Side-effects associated with imaging improved even more when
Tosten Almen
Thorsten (Thorstein, Torstein, Torsten) is a Scandinavian given name. The Old Norse name was ''Þórsteinn''. It is a compound of the theonym ''Þór'' (''Thor'') and ''steinn'' "stone", which became ''Thor'' and ''sten'' in Old Danish and Old Sw ...
published a ground-breaking thesis in 1969 based on the less toxic low-osmolar contrast media, developed based on swimming experiences in lakes with different salinity.