Ureter

The ureters are paired, thick muscular tubes with a lumen of approximately 3 mm in diameter and are 24 to 30 cm in length. They originate at the renal pelvis and function to propel urine from the kidney to the bladder. In approximately 1% of the population, the ureter is duplicated. Duplications of the ureter are characterized as partial or complete. In partial duplications, the second ureter joins the first before reaching the bladder. In complete duplications, both ureters travel side by side to the bladder. In the abdomen, the ureters lie on the medial surface of the psoas major muscle, within the retroperitoneum. The right ureter lies underneath the terminal ileum, cecum, appendix, and ascending colon, and their mesenteries. The ovarian vessels cross the right ureter at its midsection. The left ureter is adherent to the underside of the mesentery of the descending and sigmoid mesocolon, and is crossed by the inferior mesenteric and ovarian vessels. The inferior mesenteric artery is near and looks similar to the left ureter; therefore, care must be taken to distinguish these structures during dissection within this area. The ureters pass into the pelvis near the bifurcation of the common iliac vessels. As they descend into the pelvis, at the level of the ischial spine, they are in close proximity to the suspensory ligament of the ovary and form the posterior limit of the ovarian fossa. This relationship is important to recognize because injury to the ureter can occur during ligation of the infundibu-lopelvic ligament during oophorectomy. Both ureters travel parallel and medial to the obturator fossa and the internal iliac vessels. In this region of the pelvis, they are lateral to the sacrospinous ligament and pass through the para-metrium of the broad ligament to a location approximately 1.5 cm lateral to the cervix. As the ureters descend to the bladder within the broad ligament, the uterine artery crosses anteriorly (Figure 4-1.1). Within centimeters below the crossing of the ureter by the uterine artery, the inferior vesicular artery can cross the ureter anteriorly or posteriorly. The vaginal artery is posterior and medial to the ureter at this location. Here numerous arteries and veins surround both ureters and this is another common site of ureteral injury during hysterectomy. At the level of the cervix, the ureters traverse the cardinal ligament on its way to the bladder base. They travel medially on the anterior surface of the vagina for 1 to 3 cm before reaching the bladder. The ureters perforate the bladder 5 to 6 cm apart and run obliquely through the detrusor wall for 1.5 cm. The internal ureteral orifices are much closer to each other than to their external penetrations of the bladder wall. As the ureters enter the bladder, they form the trigone, which is a triangular region of the bladder base (Figure 4-1.2). The trigone is made up of a superficial and deep layer that is separate from the detrusor muscle. The superficial layer of the trigone is an extension of the inner muscular layer of the ureter. The fibers from each ureter meet to form a triangular sheet of muscle that extends from the two ureteral orifices and continues distally into the posterior aspect to the proximal urethra. The superior portion of the ureteral muscle of the trigone forms the interureteric ridge. The lateral portions of this muscle are the ureteral bars. Waldeyer's sheath is a fibromuscular sheet of tissue that originates 2 cm above the bladder and is wrapped around the ureter. This sheath extends longitudinally to the bladder neck and forms the deep portion of the trigone. The trigone sits on the muscles of the detrusor wall and anchors the ureters to the bladder. The distal intravesical portion of the ureter is submucosal and is supported by the detrusor muscle backing. As the bladder fills, urine compresses the ureter against the muscle backing, creating a flap valve, which prevents reflux of urine from the bladder into the ureter.

The arterial supply of the ureter arises from branches of various vessels as it descends into the pelvis. The abdominal sources of arterial blood supply to the ureter are the renal artery (30%), the aorta (15.4%), and the gonadal arteries (7.7%). The most significant sources of blood to the pelvic ureter are the superior vesicular arteries (12.8%), the inferior vesicular arteries (12.9%), and the internal iliac arteries (8.5%).' The ureteral veins drain at either end of the ureter and along its length. In the abdominal portion of the ureter, the main veins drain into the renal and gonadal vessels. Additional drainage occurs along other veins in the proximity of the ureter. The pelvic portion of the ureter drains into the plexus of veins within the broad ligament and other adjacent veins.

The nervous innervation of the abdominal ureters arises from the renal and aortic plexus. The pelvic ureter receives its nerve supply from the inferior hypogastric and pelvic plexus. These nerves contain cholinergic and adrenergic fibers that regulate ureteral peristalsis. Ureteral peristalsis is not activated by the nervous system, but is thought to modulate its actions.4 Afferent fibers in the lamina propria relay messages of stretch, osmolarity, and pH to the brain. There are few pain receptors in the ureter itself. Most of the pain that we perceive from ureteral obstruction is secondary to distention of the renal capsule, rather than stimula-

Common iliac artery

Uterus

Common iliac artery

Uterus

Obturator artery

Bladder

Figure 4-1.1. As the ureter descends to the bladder within the broad ligament, the uterine artery crosses it anteriorly and the vaginal artery passes underneath it.The inferior vesicular artery can cross the ureter anteriorly or posteriorly. (Reprinted with the permission of The Cleveland Clinic Foundation.)

Ureter

Internal iliac artery

External iliac artery

Uterine artery

Vaginal artery

Inferior vesical arteries

Obturator artery

Bladder

Figure 4-1.1. As the ureter descends to the bladder within the broad ligament, the uterine artery crosses it anteriorly and the vaginal artery passes underneath it.The inferior vesicular artery can cross the ureter anteriorly or posteriorly. (Reprinted with the permission of The Cleveland Clinic Foundation.)

Waldeyer sheath

Ureter

Inter ureteric ridge

Ureteral bar

- Deep trigone Detrusor muscle

Ureteral bar

Superficial trigone

Urethra

Figure 4-1.2. The trigone is a triangular region of the bladder base. It comprises a superficial and deep layer,which is derived from the ureteral musculature and Waldeyer's sheath, respectively. (Reprinted with the permission of The Cleveland Clinic Foundation.)

Waldeyer sheath

Ureteral bar

Superficial trigone

Ureter

Inter ureteric ridge

Ureteral bar

- Deep trigone Detrusor muscle

Urethra

Figure 4-1.2. The trigone is a triangular region of the bladder base. It comprises a superficial and deep layer,which is derived from the ureteral musculature and Waldeyer's sheath, respectively. (Reprinted with the permission of The Cleveland Clinic Foundation.)

tion from the ureter. The pain perceived by ureteral and renal capsular distention is likely relayed through the parasympathetic nervous system and can be referred to various sites that share the nerve roots of T11-L2, such as the genitalia, groin, and upper thigh. These are common sites of referred pain during ureteral obstruction.

Constipation Prescription

Constipation Prescription

Did you ever think feeling angry and irritable could be a symptom of constipation? A horrible fullness and pressing sharp pains against the bladders can’t help but affect your mood. Sometimes you just want everyone to leave you alone and sleep to escape the pain. It is virtually impossible to be constipated and keep a sunny disposition. Follow the steps in this guide to alleviate constipation and lead a happier healthy life.

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