Retroperitoneum I: Organs and Posterior Abdominal Wall PDF

Retroperitoneum I: Organs and posterior abdominal wall Bi-Hung Peng, PhD Department of Neurobiology The University of Texas Medical Branch Retroperitoneum Structures associated with the retroperitoneum Kidneys Ureters Suprarenal glands Aorta IVC Posterior wall...

Retroperitoneum I: Organs and posterior abdominal wall Bi-Hung Peng, PhD Department of Neurobiology The University of Texas Medical Branch Retroperitoneum Structures associated with the retroperitoneum Kidneys Ureters Suprarenal glands Aorta IVC Posterior wall muscles Diaphragm Lymphatic drainage Nerves & nerve plexuses (next lecture)  Location of kidneys and ureters Kidneys lie against posterior abdominal wall, protected by floating ribs. Note that right kidney is lower than left kidney (because of the liver). Hilum points medially, ureters descend at the level of the tips of vertebral transverse processes. Kidneys move up and down with each respiratory cycle (~ 1 inch). Location of the kidneys Posterior view  External anatomy of the kidney Flat organ posteriorly and anteriorly: AP order of hilar structures: 1) Renal vein 2) Renal artery 3) Ureter Fetal kidney Adult kidney (lobulated) (anterior view)  Internal anatomy of the kidney Medulla Cortex (collecting ducts) (nephrons) Pyramids: Base: at corticomedullary junction Apex: renal papillae Collecting system Sinus (“empty” space)  Collecting system of the kidney Renal papilla Minor calyx Major calyx Renal Pelvis Umbrella cell Ureter Segmental arterial supply to the kidney Five segmental branches: Superior Middle (2) Inferior Posterior They are all end arteries. “Acute glomerulonephritis”  Suprarenal (Adrenal) glands Different shapes: - Right: pyramidal - Left: crescent Arterial supply: - Superior - Medial - Inferior Venous drainage: - Only one vein each (which defines their hilum) Hormones: The adrenal cortex produces hormones that controls sex Anterior view - Cortex: steroid (androgens, estrogens), salt balance in the blood (aldosterone), - Medulla: and sugar balance (cortisol). The catecholamines adrenal medulla produces Adrenal insufficiency hormones involved in the fight-or- flight response (catecholamines, or Transverse section (Addison’s disease) adrenaline type hormones such as Adrenal Gland Function: What Do the Adrenal Glands Do?  Variation of renal arteries Variations due to kidney development: start in pelvis and ascend to final location, reestablishing vascular supply along the process. If final arteries do not coalesce, they are known as accessory (segmental) renal arteries. Inferior accessory can compress ureter and lead to hydronephrosis.  Hydronephrosis Note dilated calyces and renal pelvis  Fusion malformation of kidneys During development, kidneys may fuse while they ascend. The IMA stops the ascending of fused kidneys. Note anterior (vs. posterior) location of ureters. Sigmoid Horseshoe Horseshoe kidney IMA uriters  Kidney stones Three anatomical narrowing sites: Ureteropelvic junction Crossing of iliac arteries Ureterovesical junction  These are common locations where kidney stones lead to obstruction. Referred pain for kidney stones  Types of kidney stones Calcium (82%) Uric Acid (7%) Struvite (7%) Cystine (1-3%)  Diagnosis of kidney stones What is typically used in most ERs is non-contrast CT scan. Capable of detecting most stone types, except very rare stones caused by protease inhibitors (complication of HIV therapeutics).  The ureters They connect the kidneys to the urinary bladder and descend at the level of the transverse processes of the lumbar vertebrae. Considerable vascular supply. As the kidney ascends from the pelvis, the ureter becomes vascularized by branches from nearby vessels, which remain into adulthood.  Surgical approaches to the kidney Donor: avoid going through peritoneal cavity. Receipient: kidney is placed in the iliac fossa (inside peritoneal cavity)  Vasculature of posterior wall Aorta - Unpaired vessel. - Lies anterior to vertebral column, on the left-hand side. - Origin of paired vessels - Terminates as common iliac arteries, at the level of L4-L5. Inferior vena cava (IVC)  Paired arteries of aorta Inferior phrenic 1 Middle suprarenal 2 Renal 3 1 Testicular/ovarian 2 (gonadal) 4 3 Lumbar (multiple) Common iliac 4  IVC drainage of gonadal vein Right tributaries drain into IVC directly Left tributaries drain into left renal vein Note relative positions of left renal vein and SMA  “Anatomical nutcracker”  Anatomical nutcracker SM A Left renal vein u l ar vein c Testi  Varicocele Dilation of pampiniform plexus Seen as worm-like dilation in upper scrotum Found in middle-aged and older males Usually on left side Due to higher pressure on venous system on the left – cumulative effect  Diaphragm: structure Central tendon Peripheral skeletal muscles: - Vertebral or crural Fusion points can lead to defects - Costal which may result in herniations - Sternal  Diaphragm: function and innervation Function: changes intra-abdominal and thoracic pressures. - Contraction  Descends  Inspiration. Innervation: - Phrenic: motor and sensory - Thoracic: sensory only.  Openings in the diaphragm During mid-inspiration: IVC: T8 1 Esophagus: T10 2 Aorta: T12 (does not actually pierce 1 the diaphragm) 3 2 1 2 3 3  Muscles of the posterior abdominal wall For orientation, locate: - Lumbar vertebrae - Iliac wings (fossa) - 12th rib Diaphragm Quadratus lumborum Transversus abdominis Psoas - Major and minor Iliacus Lymphatic drainage of testes/scrotum & abdomen Cisterna chyli (to thoracic duct) Intestinal nodes (pre-aortic) Lumbar nodes (para-aortic) Iliac nodes Deep inguinal nodes Superficial inguinal nodes Testicular Scrotal drainage drainage Questions?