Posterior Abdominal Wall: Anatomy

The posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen is a complex musculoskeletal structure that houses the abdominal aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy, the inferior vena cava Inferior vena cava The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs. Mediastinum and Great Vessels: Anatomy, as well as important retroperitoneal Retroperitoneal Peritoneum: Anatomy organs, like the kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy, renal glands, pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy, and duodenum Duodenum The shortest and widest portion of the small intestine adjacent to the pylorus of the stomach. It is named for having the length equal to about the width of 12 fingers. Small Intestine: Anatomy. This vital anatomical structure consists of the posterior abdominal muscles, their respective fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis, lumbar vertebrae Lumbar vertebrae Vertebrae in the region of the lower back below the thoracic vertebrae and above the sacral vertebrae. Vertebral Column: Anatomy, and the pelvic girdle. The structure is supported by 12th thoracic rib, lumbar vertebrae Lumbar vertebrae Vertebrae in the region of the lower back below the thoracic vertebrae and above the sacral vertebrae. Vertebral Column: Anatomy, and pelvic rim.

Last updated: 9 Mar, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Introduction

Posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen

  • Complex musculoskeletal structure representing the posterior boundary of the abdominal cavity
  • Supports retroperitoneal Retroperitoneal Peritoneum: Anatomy organs and contains important neurovascular structures
  • Boundaries:
    • Anteriorly by: 
      • Anterolateral abdominal muscles
      • Retroperitoneal Retroperitoneal Peritoneum: Anatomy organs
      • Parietal Parietal One of a pair of irregularly shaped quadrilateral bones situated between the frontal bone and occipital bone, which together form the sides of the cranium. Skull: Anatomy peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum: Anatomy
    • Posteriorly by: 
      • Lumbar vertebrae Lumbar vertebrae Vertebrae in the region of the lower back below the thoracic vertebrae and above the sacral vertebrae. Vertebral Column: Anatomy
      • Muscles
      • Fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis 
    • Superiorly by the 12th rib and diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy 
    • Inferiorly by the pelvic brim
Skeletal boundaries of the posterior abdominal wall

Skeletal boundaries of the posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen:
On the left, boundaries (marked by green): superior boundary: 12th ribs Ribs A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs. Chest Wall: Anatomy, inferior boundary: pelvic brim. The lumbar vertebrae Lumbar vertebrae Vertebrae in the region of the lower back below the thoracic vertebrae and above the sacral vertebrae. Vertebral Column: Anatomy represent the posterior boundary.

Image by Lecturio.

Structures

  • Fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis
  • Muscles
    • Diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
    • Psoas major and minor
    • Iliacus muscle
    • Quadratus lumborum
  • Extraperitoneal fat
  • Parietal Parietal One of a pair of irregularly shaped quadrilateral bones situated between the frontal bone and occipital bone, which together form the sides of the cranium. Skull: Anatomy peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum: Anatomy
  • Vasculature 
  • Somatic innervation: subcostal nerve and lumbar plexus

Fascia and Related Structures of the Posterior Abdominal Wall

Thoracolumbar fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis

Large area of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology that is made up of 3 layers:

  • Posterior:
    • Extends from the 12th rib to the iliac crest
    • Laterally goes to the internal oblique Internal oblique Muscles of the anterolateral abdominal wall consisting of the external oblique and the internal oblique muscles. The external abdominal oblique muscle fibers extend from lower thoracic ribs to the linea alba and the iliac crest. The internal abdominal oblique extend superomedially beneath the external oblique muscles. Anterior Abdominal Wall: Anatomy and transversus abdominis Transversus abdominis Anterior Abdominal Wall: Anatomy muscles
    • Overlies the latissimus dorsi muscle
  • Middle:
    • Together with the anterior layer, encloses the quadratus lumborum muscle
    • Together with the posterior layer, encloses the deep muscles of the back Muscles of the back The back is composed of several muscles of varying sizes and functions, which are grouped into intrinsic (or primary) back muscles and extrinsic (or secondary) back muscles. The extrinsic muscles comprise the superficial and intermediate muscle groups, while the intrinsic muscles comprise the deep muscles. Muscles of the Back: Anatomy
  • Anterior:

Psoas fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis

  • Covers the psoas major muscle 
  • Thickened superiorly, forming medial arcuate ligament
  • Medially adheres to the lumbar vertebrae Lumbar vertebrae Vertebrae in the region of the lower back below the thoracic vertebrae and above the sacral vertebrae. Vertebral Column: Anatomy and pelvic brim
  • Continues with part of the iliac fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis inferiorly and the thoracolumbar fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis laterally
Abdominal wall muscles and the thoracolumbar fascia

Abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen muscles and the thoracolumbar fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis (cross section at L3 level):
ES: erector spinae
LD: latissimus dorsi
PM: psoas major
QL: quadratus lumborum

Image by Lecturio.

Lumbar triangles

Similarly to the anterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen, herniation Herniation Omphalocele can occur in weakened areas in the posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen. These herniations occur in the Grynfeltt-Lesshaft triangle (inferior lumbar triangle) or Petit triangle (superior lumbar triangle).

  • Inferior lumbar (Petit) triangle:
    • Lies superficially 
    • Sometimes called the lumbar triangle
    • Bound by:
      • External oblique External oblique Muscles of the anterolateral abdominal wall consisting of the external oblique and the internal oblique muscles. The external abdominal oblique muscle fibers extend from lower thoracic ribs to the linea alba and the iliac crest. The internal abdominal oblique extend superomedially beneath the external oblique muscles. Anterior Abdominal Wall: Anatomy muscle anteriorly
      • Latissimus dorsi muscle posteriorly
      • Iliac crest inferiorly
  • Superior lumbar (Grynfeltt-Lesshaft) triangle: 
    • Deep; size varies per individual.
    • More commonly the site of herniation Herniation Omphalocele
    • Bound by:
      • Quadratus lumborum medially
      • Inferior oblique Inferior oblique Orbit and Extraocular Muscles: Anatomy muscle laterally
      • 12th rib superiorly
      • Transversalis fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis as the floor of the triangle
      • External abdominal oblique as the roof of the triangle
Lumbar triangles

Lumbar triangles:
a: Superior lumbar triangle
b: Inferior lumbar triangle

Image: “Lumbar triangles” by Marc Rafols et al AL Amyloidosis. License: CC BY 4.0

Muscles and Bones

Muscles

  • Diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy:
    • Forms superior border of the posterior abdominal region
    • Consists of 3 parts: 
      • Sternal 
      • Costal 
      • Lumbar
    • Contains 3 important apertures: 
    • Origin: 
    • Insertion: the middle part of the central tendon Central tendon Diaphragm: Anatomy
    • Functions: 
      • Major muscle of respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose and Nasal Cavity: Anatomy, helping in inhalation (contraction) and expiration Expiration Ventilation: Mechanics of Breathing (relaxation)
      • Abdominal straining (increasing intraabdominal pressure)
      • Separates the abdominal cavity from the thoracic cavity 
    • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology innervation: right and left phrenic nerves (originate from cervical spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy: C3–C5)
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation:
      • Phrenic nerve Phrenic nerve The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm. Diaphragm: Anatomy: for central part of diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
      • 6th–11th intercostal nerves for periphery of diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
  • Quadratus lumborum:
    • Posterior to the kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy, lateral to psoas muscles
    • Origin: posterior border of the iliac crest
    • Insertion: L1–L4 vertebrae and inferior border of 12th rib
    • Functions: 
      • Laterally flexes the lumbar vertebrae Lumbar vertebrae Vertebrae in the region of the lower back below the thoracic vertebrae and above the sacral vertebrae. Vertebral Column: Anatomy
      • Stabilizes the 12th rib during respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose and Nasal Cavity: Anatomy
    • Innervation: subcostal (T12) and lumbar (L1–L4) nerves
  • Psoas:
    • Major
    • Minor
      • Origin: T12 and L1 vertebrae
      • Insertion: attaches to the pectineal line on the superior pubic ramus
      • Function: weak flexor of the trunk
      • Innervation: ventral rami of L1–L3
  • Iliacus:
    • Origin: iliac fossa
    • Insertion: lesser trochanter of the femur 
    • Function: flexes thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy at the hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy 
    • Innervation: ventral rami of L2–L4 ( femoral nerve Femoral Nerve A nerve originating in the lumbar spinal cord (usually L2 to L4) and traveling through the lumbar plexus to provide motor innervation to extensors of the thigh and sensory innervation to parts of the thigh, lower leg, and foot, and to the hip and knee joints. Femoral Region and Hernias: Anatomy)

Support of the posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen

  • 12th thoracic rib
  • Vertebral column Vertebral column The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy:
    • 12th thoracic vertebrae Thoracic vertebrae A group of twelve vertebrae connected to the ribs that support the upper trunk region. Vertebral Column: Anatomy
    • Lumbar vertebrae Lumbar vertebrae Vertebrae in the region of the lower back below the thoracic vertebrae and above the sacral vertebrae. Vertebral Column: Anatomy (L1–L5)
    • Sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy
  • Ilium:
    • Largest of the 3 bones that merge to form the hip bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types
    • The iliac crest (the curved superior border of the ilium) forms the inferior boundary of the posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen.
Superior view of the pelvic girdle, 4 primary joints of the pelvis

Superior view of the pelvic girdle and the 4 primary joints of the pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy

Image by Lecturio.

Vasculature and Lymphatic Drainage

Abdominal aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy

  • Relation:
    • Continuation of the thoracic aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy
    • Enters the abdomen through the aortic hiatus Aortic hiatus Diaphragm: Anatomy in the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy at the level of the T12 vertebra
    • Travels down the posterior wall of the abdomen (anterior to the vertebral column Vertebral column The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy)
    • Divides into the common iliac arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology at L4
  • Different arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology branch out from the anterior, lateral, and posterior parts of the abdominal aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy:
    • Unpaired branches:
      • Celiac trunk
      • Superior mesenteric artery Superior mesenteric artery A large vessel supplying the whole length of the small intestine except the superior part of the duodenum. It also supplies the cecum and the ascending part of the colon and about half the transverse part of the colon. It arises from the anterior surface of the aorta below the celiac artery at the level of the first lumbar vertebra. Small Intestine: Anatomy
      • Inferior mesenteric artery Inferior mesenteric artery The artery supplying nearly all the left half of the transverse colon, the whole of the descending colon, the sigmoid colon, and the greater part of the rectum. It is smaller than the superior mesenteric artery and arises from the aorta above its bifurcation into the common iliac arteries. Small Intestine: Anatomy
      • Median Median After arranging the data from loWest to highest, the median is the middle value, separating the lower half from the upper half of the data set. Measures of Central Tendency and Dispersion sacral artery
    • Paired branches:
      • Middle adrenal/suprarenal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
      • Renal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
      • Gonadal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
      • Inferior phrenic arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
      • Lumbar arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
      • Common iliac arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology ( aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy bifurcates)
Table: Branches of the abdominal aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy
Location in the abdominal aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy Branches ( arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology) of the abdominal aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy Level Paired or unpaired
Anterior Celiac trunk T12 Unpaired
Superior mesenteric L1
Inferior mesenteric L3
Lateral Middle suprarenal/adrenal L1 Paired
Renal L1 to L2
Gonadal (testicular or ovarian) L2
Dorsal Inferior phrenic T12 Paired
Lumbar (4) L1, L2, L3, L4
Median Median After arranging the data from loWest to highest, the median is the middle value, separating the lower half from the upper half of the data set. Measures of Central Tendency and Dispersion sacral L4 (above the bifurcation) Unpaired
Terminal Common iliac L4 Paired
Vascular structures in the posterior abdominal wall

Vascular structures in the posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen (in relation to the kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy and skeletal frame)

Image by Lecturio.

Inferior vena cava Inferior vena cava The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs. Mediastinum and Great Vessels: Anatomy

  • Relations:
    • Formed at the L5 level by the 2 common iliac veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
    • Ascends to the right of the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy
    • Goes through the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy at the T8 level
  • Tributaries:
    • Hepatic veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
    • Inferior phrenic veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology
    • Right suprarenal vein
    • Right gonadal vein
    • Renal veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology: The left gonadal, inferior phrenic and suprarenal veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology enter the left renal vein Renal vein Short thick veins which return blood from the kidneys to the vena cava. Glomerular Filtration, which then drains into the inferior vena cava Inferior vena cava The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs. Mediastinum and Great Vessels: Anatomy.
    • Lumbar veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology

Lymphatic drainage

  • Most lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy are located beside the vascular channels Channels The Cell: Cell Membrane running along the posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen.
  • Lymphatic drainage:
    • GI tract: superior and inferior mesenteric lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy
    • Adrenal glands Adrenal Glands The adrenal glands are a pair of retroperitoneal endocrine glands located above the kidneys. The outer parenchyma is called the adrenal cortex and has 3 distinct zones, each with its own secretory products. Beneath the cortex lies the adrenal medulla, which secretes catecholamines involved in the fight-or-flight response. Adrenal Glands: Anatomy and retroperitoneum: lumbar or para-aortic lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy
    • Urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy: iliac and lumbar lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy
    • Gonads Gonads The gamete-producing glands, ovary or testis. Hormones: Overview and Types/reproductive tract: lumbar, iliac inguinal lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy
  • All drain the abdominal viscera into the cisterna chyli through the right and left lumbar and intestinal trunks.

Innervation

Somatic innervation comes from the ventral rami of the subcostal and lumbar spinal nerves Spinal nerves The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included. Spinal Cord: Anatomy

  • Subcostal nerve:
    • From the ventral ramus of T12
    • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology supply to the abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen muscles ( external oblique External oblique Muscles of the anterolateral abdominal wall consisting of the external oblique and the internal oblique muscles. The external abdominal oblique muscle fibers extend from lower thoracic ribs to the linea alba and the iliac crest. The internal abdominal oblique extend superomedially beneath the external oblique muscles. Anterior Abdominal Wall: Anatomy, internal oblique Internal oblique Muscles of the anterolateral abdominal wall consisting of the external oblique and the internal oblique muscles. The external abdominal oblique muscle fibers extend from lower thoracic ribs to the linea alba and the iliac crest. The internal abdominal oblique extend superomedially beneath the external oblique muscles. Anterior Abdominal Wall: Anatomy, transverse abdominis, and rectus abdominis Rectus Abdominis A long flat muscle that extends along the whole length of both sides of the abdomen. It flexes the vertebral column, particularly the lumbar portion; it also tenses the anterior abdominal wall and assists in compressing the abdominal contents. It is frequently the site of hematomas. In reconstructive surgery it is often used for the creation of myocutaneous flaps. Anterior Abdominal Wall: Anatomy)
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation to the T12 dermatome Dermatome Spinal Disk Herniation (anterolateral region)
  • Lumbar plexus:
    • Iliohypogastric nerve:
      • Origin: ventral rami of L1 spinal nerves Spinal nerves The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included. Spinal Cord: Anatomy
      • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology innervation: supplies the internal oblique Internal oblique Muscles of the anterolateral abdominal wall consisting of the external oblique and the internal oblique muscles. The external abdominal oblique muscle fibers extend from lower thoracic ribs to the linea alba and the iliac crest. The internal abdominal oblique extend superomedially beneath the external oblique muscles. Anterior Abdominal Wall: Anatomy and transversus abdominis Transversus abdominis Anterior Abdominal Wall: Anatomy muscles
      • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation: hypogastric region
    • Ilioinguinal nerve Ilioinguinal nerve Inguinal Canal: Anatomy and Hernias:
      • Origin: ventral rami of L1
      • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology innervation: internal oblique Internal oblique Muscles of the anterolateral abdominal wall consisting of the external oblique and the internal oblique muscles. The external abdominal oblique muscle fibers extend from lower thoracic ribs to the linea alba and the iliac crest. The internal abdominal oblique extend superomedially beneath the external oblique muscles. Anterior Abdominal Wall: Anatomy and transversus abdominis Transversus abdominis Anterior Abdominal Wall: Anatomy muscles along with the iliohypogastric nerve
      • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation: superomedial aspect of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy and anterior surface of the external genitalia
    • Genitofemoral nerve Genitofemoral nerve Inguinal Canal: Anatomy and Hernias:
    • Femoral nerve Femoral Nerve A nerve originating in the lumbar spinal cord (usually L2 to L4) and traveling through the lumbar plexus to provide motor innervation to extensors of the thigh and sensory innervation to parts of the thigh, lower leg, and foot, and to the hip and knee joints. Femoral Region and Hernias: Anatomy:
      • Origin: L2–L4 spinal nerves Spinal nerves The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included. Spinal Cord: Anatomy
      • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology innervation: pectineus Pectineus Thigh: Anatomy, sartorius Sartorius Thigh: Anatomy, rectus femoris Rectus femoris Thigh: Anatomy, vastus lateralis Vastus lateralis Thigh: Anatomy, vastus medialis Vastus medialis Thigh: Anatomy, and vastus intermedius Vastus intermedius Thigh: Anatomy
      • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation: gives rise to the medial and intermediate cutaneous nerves of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy, supplying the anterior thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy and medial leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy
      • Joints: innervates hip and knee joints
    • Lateral femoral cutaneous nerve:
      • Lateral cutaneous nerve of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
      • Origin: L2–L3 spinal nerves Spinal nerves The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included. Spinal Cord: Anatomy
      • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation: cutaneous sensation from the lateral part of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
      • No motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology function
    • Obturator nerve Obturator Nerve A nerve originating in the lumbar spinal cord (L2 to L4) and traveling through the lumbar plexus to the lower extremity. The obturator nerve provides motor innervation to the adductor muscles of the thigh and cutaneous sensory innervation of the inner thigh. Thigh: Anatomy:
      • Origin: L2–L4 spinal nerves Spinal nerves The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included. Spinal Cord: Anatomy
      • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology innervation: medial thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy compartment (hip adductors)
      • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation: medial aspect of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
    • Accessory obturator nerve Obturator Nerve A nerve originating in the lumbar spinal cord (L2 to L4) and traveling through the lumbar plexus to the lower extremity. The obturator nerve provides motor innervation to the adductor muscles of the thigh and cutaneous sensory innervation of the inner thigh. Thigh: Anatomy: present in about 30% of cases (comes from L3–L4 spinal nerves Spinal nerves The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included. Spinal Cord: Anatomy)
Lumbosacral plexus

Lumbosacral plexus:
Innervation to the posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen comes from the ventral rami of the subcostal and lumbar spinal nerves Spinal nerves The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included. Spinal Cord: Anatomy.

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Clinical Relevance

  • Hiccups: involuntary, spasmodic contractions of the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy, leading to quick inhalations that are interrupted by the involuntary closure of the glottis Glottis The vocal apparatus of the larynx, situated in the middle section of the larynx. Glottis consists of the vocal folds and an opening (rima glottidis) between the folds. Larynx: Anatomy. Hiccups can result from irritation of nerve endings or of medullary centers in the brain stem Brain Stem The brain stem is a stalk-like structure that connects the cerebrum with the spinal cord and consists of the midbrain, pons, and medulla oblongata. It also plays a critical role in the control of cardiovascular and respiratory function, consciousness, and the sleep-wake cycle. Brain Stem: Anatomy (which control respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose and Nasal Cavity: Anatomy). Among the causes are indigestion, diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy irritation, alcoholism Alcoholism A primary, chronic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. The disease is often progressive and fatal. It is characterized by impaired control over drinking, preoccupation with the drug alcohol, use of alcohol despite adverse consequences, and distortions in thinking, most notably denial. Each of these symptoms may be continuous or periodic. Wernicke Encephalopathy and Korsakoff Syndrome, cerebral lesions, and thoracic and abdominal lesions, all of which disturb the phrenic nerves.
  • Congenital Congenital Chorioretinitis diaphragmatic hernias: embryologically derived defects in the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy through which abdominal structures can pass into the chest cavity. Prenatal diagnosis is commonly made by ultrasonography during pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care followed by confirmation on chest x-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests after birth. Immediate respiratory resuscitation Resuscitation The restoration to life or consciousness of one apparently dead. . Neonatal Respiratory Distress Syndrome at birth with endotracheal intubation Endotracheal Intubation Neonatal Respiratory Distress Syndrome and mechanical ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing are required. Surgical repair is the only curative option. Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas varies, but children with diaphragmatic hernias usually suffer from lifelong pulmonary complications. 
  • Psoas sign Psoas sign When there is RLQ pain with passive hip extension (characteristic of retrocecal appendix) Appendicitis: abdominal exam finding in acute appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis. Finding is RLQ pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways with passive right hip extension Extension Examination of the Upper Limbs (characteristic of retrocecal appendix Retrocecal appendix Appendicitis, where the inflamed appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy lies against the right psoas muscle Psoas muscle A powerful flexor of the thigh at the hip joint (psoas major) and a weak flexor of the trunk and lumbar spinal column (psoas minor). Psoas is derived from the greek ‘psoa. Pyelonephritis and Perinephric Abscess).
  • Psoas abscess Psoas abscess Abscess of the psoas muscles resulting usually from disease of the lumbar vertebrae, with the pus descending into the muscle sheath. The infection is most commonly tuberculous or staphylococcal. Pyelonephritis and Perinephric Abscess: purulent collection in the iliopsoas muscle compartment. The condition can be secondary to spread from adjacent structures or by hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases spread from a distant site. Staphylococcus aureus Staphylococcus aureus Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications. Brain Abscess is the most common bacterium causing this infection. Tuberculosis-related abscesses  are seen in regions where Mycobacterium tuberculosis Mycobacterium tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis is endemic. Common signs and symptoms include back pain Back pain Back pain is a common complaint among the general population and is mostly self-limiting. Back pain can be classified as acute, subacute, or chronic depending on the duration of symptoms. The wide variety of potential etiologies include degenerative, mechanical, malignant, infectious, rheumatologic, and extraspinal causes. Back Pain, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, and abdominal and flank pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways. Diagnosis is via CT scan, along with cultures Cultures Klebsiella of blood and abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease material. Management includes drainage and use of appropriate antibiotics.
  • Pyelonephritis Pyelonephritis Pyelonephritis is infection affecting the renal pelvis and the renal parenchyma. This condition arises mostly as a complication of bladder infection that ascends to the upper urinary tract. Pyelonephritis can be acute or chronic (which results from persistent or chronic infections). Typical acute symptoms are flank pain, fever, and nausea with vomiting. T Pyelonephritis and Perinephric Abscess: infection affecting the renal pelvis Renal pelvis Kidneys: Anatomy and the renal parenchyma. This condition arises mostly from a bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess infection ascending to the upper urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy. Typical symptoms are flank pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, and nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics with vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia. The kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy can be examined through the costovertebral angle (formed by the 12th rib and vertebral column Vertebral column The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy) of the posterior abdominal wall Abdominal wall The outer margins of the abdomen, extending from the osteocartilaginous thoracic cage to the pelvis. Though its major part is muscular, the abdominal wall consists of at least seven layers: the skin, subcutaneous fat, deep fascia; abdominal muscles, transversalis fascia, extraperitoneal fat, and the parietal peritoneum. Surgical Anatomy of the Abdomen. The diagnosis is established via clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor and laboratory findings (in blood and urine Urine Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the urethra. Bowen Disease and Erythroplasia of Queyrat). Imaging studies are performed if severe illness is noted or if there is no response to initial treatment (antibiotics).

References

  1. Drake, R., Vogl, A.W.,  Mitchell, A. (2020) Regional anatomy, posterior abdominal region. Chapter 4 of Gray’s Anatomy for Students, 4th ed. Churchill Livingstone/Elsevier, pp. 365–373.
  2. Moore, K. L., Dalley, A. F., Agur, A. M. R. (2014). Abdomen. Chapter 2 of Clinically Oriented Anatomy, 7th ed. Lippincott Williams & Wilkins, pp. 309–321.
  3. Morton D.A., Foreman K., Albertine, K.H. (Eds.) (2019). Posterior abdominal wall. In: The Big Picture: Gross Anatomy, 2nd ed. McGraw-Hill. Retrieved from https://accessmedicine.mhmedical.com/content.aspx?bookid=2478&sectionid=202020626
  4. Nunn, J.F., Khan, Y.S. (2020). Anatomy, abdomen and pelvis, posterior abdominal wall nerves. StatPearls. Retrieved from: https://www.ncbi.nlm.nih.gov/books/NBK557605/

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