Ureter anatomy

Overview

• Length: 25cm
  • Pelvic component forms about half of this length
• Points of narrowest calibre:
  • Pelviureteric Junction
  • Where it crosses the Pelvic Brim
  • As it passes through the Bladder wall
• Adheres to the Peritoneum of the posterior abdominal wall when that membrane is stripped off the posterior abdominal wall
• Distinguished from vessels and nerves in the living body in that it is whitish, non-pulsatile cord which shows peristaltic activity when gently pinched with forceps.

Course and Relations

• Course:
  • Pass down on Psoas Major under cover of Peritoneum
  • Crosses in front of the Genitofemoral Nerve
  • Crossed anteriorly by the Gonadal Vessels
  • On the Right:
    • Upper part posterior to the 3rd part of the Duodenum
    • Lower down – crossed anteriorly by the Right Colic and Ileocolic Vessels and Root of Small Bowel Mesentery
  • On the Left:
    • Lateral to the Inferior Mesenteric Vessels
    • Crossed anteriorly by the Left Colic Vessels
    • At the Pelvic Brim, crossed anteriorly by the Apex of the Sigmoid Mesocolon
  • Leaves Psoas Muscle at the bifurcation of the Common Iliac Artery over the Sacroiliac Joint
  • Passes into the Pelvis
  • Runs over the External Iliac Artery and Vein
  • Runs down the side wall of the pelvis in front of the Internal Iliac Artery (Behind the Ovary)
  • In order from above downwards, it crosses the:
    • Obturator Nerve
    • Obliterated Umbilical (Superior Vesical) Artery
    • Obturator Artery
    • Obturator Vein
  • Turns forwards and medially above pelvic floor
  • Enters base of Bladder at its upper lateral angles of the Trigone
    • In the male: the Vas Deferens crosses above the Ureter and then runs down medial to the Ureter
      • Upper end of Seminal Vesicles usually lies just below the point where the Ureter enters the Bladder Wall
    • In the female: Ureter lies in the base of the Broad Ligament where it is crossed above by the Uterine Artery
      • Under the Broad Ligament, the Ureter penetrates the condensed tissue that forms the Lateral Cervical Ligament
      • Crosses the Lateral Vaginal Fornix 1-2cm from the Cervix before entering the Bladder in front of the Fornix

• Locating the ureter intra-operatively:

  • Over the bifurcation of the Common Iliac Artery over the Sacroiliac Joint
  • At the apex of the sigmoid mesentry
  • Chase the gonadal vessels as they will cross over the ureter

• Surface markings:

  • Anterior abdominal wall – marked from the tip of the 9th costal cartilage to the birfucation of the Common Iliac Artery

• Line of projection of the Ureter on a radiograph:

  • Lies medial to the tips of the transverse processes of the Lumbar Vertebrae
  • Crosses Pelvic Brim at the Sacroiliac Joint
  • From here, pelvic shadow passes to the Ischial Spine
  • Then, foreshortened, to the Pubic Tubercle

Blood Supply

• Upper end: Ureteric branch of the Renal Artery
• Middle section: Abdominal Aorta, Gonadal, Common Iliac and Internal Iliac Arteries
• Lower end: Inferior and Superior Vesical and Uterine Arteries
• All vessels form good anastomosis with each other in the Adventitia of the Ureter forming longitudinal channels
  • Blood supply is endangered if Ureter stripped clean of its surrounding tissue

Lymphatic Drainage

• Run back alongside the arteries
• Abdominal portion of Ureter ⇒ Drain to Para-aortic Nodes
• Pelvic portion of Ureter ⇒ Drain to Common Iliac and Internal Iliac Nodes

Nerve Supply

• Sympathetic fibres: From T10-L1 segments of the spinal cord via the Coeliac and Hypogastric Plexuses
• Parasympathetic fibres: From the Pelvic Splanchnic Nerves
• Functional significance of these innervations is unclear
• Intact innervation of Renal Pelvis and Ureter not necessary for the initiation or propagation of peristalsis from the Calyceal Pacemakers
• No ganglion cells in or on the Ureter
• Pain fibres – accompany sympathetic nerves

Structure

• Smooth muscle
• Lined internally by mucous membrane
  • Lax
  • Lined by transitional epithelium
• No muscularis mucosae
• Inner longitudinal, middle circular, and outer longitudinal
• More accurate to consider the muscle as a single coat with fibres running in many different directions

Development

• Mesodermal origin
• Derived by a process of budding from the caudal end of the Mesonephric Duct
• Upper end divides into 2 or 3 (the Major Calyces of the Renal Pelvis)
  • Further subdivisions produce the Minor Calyces and Collecting Tubules
• Low division of the Ureteric Bud produces the Double Ureter