Surgical Anatomy of the Abdomen

Surface Anatomy of the Abdomen

Boundaries

Superior:

• Xiphoid process Xiphoid process Chest Wall: Anatomy
• Costal cartilages of the 7th–10th 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:

• Pubic 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 and pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy
• Inguinal ligaments

Lateral: 

• Superior: inferior aspect of the 10th rib
• Inferior: iliac crest

Landmarks

• Umbilicus
• Linea alba: fibrous Fibrous Fibrocystic Change junction of the right and left rectus muscles that runs down the midline of the abdomen 
• Semilunar lines: lateral borders of the 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 muscles
• Anterior superior iliac spine Anterior Superior Iliac Spine Chronic Apophyseal Injury
• Iliac crests 
• Pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy
• Inguinal grooves

Lines and planes

The following divide the abdomen into its 9 regions:

• Right and left midclavicular lines
• Subcostal plane Subcostal Plane Anterior Abdominal Wall: Anatomy
• Transtubercular, or intertubercular, plane

Regions of the abdomen

• Right and left hypochondria
• Epigastrium
• Right and left lateral abdominal regions or flanks 
• Umbilical
• Right and left inguinal regions or iliac fossae 
• Hypogastrium Hypogastrium Anterior Abdominal Wall: Anatomy

Dermatomes Dermatomes Spinal Cord: Anatomy

• T7–L1
• Visceral pains are named according to their respective dermatomes Dermatomes Spinal Cord: Anatomy. 

Epigastrium

The epigastrium contains the transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy, the 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, and the 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.

Transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy

• Part of the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy distal to the ascending colon Ascending colon The segment of large intestine between the cecum and the transverse colon. It passes cephalad from the cecum to the caudal surface of the right lobe of the liver where it bends sharply to the left, forming the right colic flexure. Colon, Cecum, and Appendix: Anatomy and proximal to the descending colon Descending colon The segment of large intestine between transverse colon and the sigmoid colon. Colon, Cecum, and Appendix: Anatomy that travels transversely across the upper abdomen
• Suspended by mesentery Mesentery A layer of the peritoneum which attaches the abdominal viscera to the abdominal wall and conveys their blood vessels and nerves. Peritoneum: Anatomy (transverse mesocolon)
• Supplied by ileocolic and middle colic branches of the 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
• Venous drainage is through the superior mesenteric vein that joins the portal vein Portal vein A short thick vein formed by union of the superior mesenteric vein and the splenic vein. Liver: Anatomy.

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

• First C-shaped segment of the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy
• Surrounds the head of the 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
• Consists of 4 segments
• The 2nd, or descending, segment contains the ampulla of Vater (opening of the common bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct).
• 1st segment (duodenal bulb): intraperitoneal Intraperitoneal Peritoneum: Anatomy
• Descending, horizontal, and ascending parts: retroperitoneal Retroperitoneal Peritoneum: Anatomy
• Ends at duodenojejunal flexure: fixed to the posterior abdominal wall Posterior abdominal wall The posterior abdominal wall is a complex musculoskeletal structure that houses the abdominal aorta, the inferior vena cava, as well as important retroperitoneal organs, like the kidneys, renal glands, pancreas, and duodenum. Posterior Abdominal Wall: Anatomy by the ligament of Treitz Ligament of treitz Gastrointestinal Bleeding

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

Segments:

• Caput pancreatis (head)
• Uncinate process
• Collum pancreatis ( neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess)
• Corpus pancreatis (body)
• Cauda pancreatis (tail): the only intraperitoneal Intraperitoneal Peritoneum: Anatomy segment of the 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 

Ducts:

• Pancreatic duct (Wirsung’s duct) and common bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct open into ampulla of Vater, which presents as major duodenal papilla.
• Major duodenal papilla contains the hepatopancreatic sphincter (sphincter of Oddi), which regulates the secretion Secretion Coagulation Studies of bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy and pancreatic fluid.
• Accessory pancreatic duct Accessory pancreatic duct Pancreas: Anatomy (when present) opens into minor duodenal papilla.

Relevant procedures

• Transverse colostomy: an opening along the length of the transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy to the exterior skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions surface
• Transverse hemicolectomy: surgical removal of the transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy
• Pancreaticojejunostomy (Puestow procedure): surgically made communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence between the 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 the jejunum Jejunum The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum. Small Intestine: Anatomy (treatment of chronic pancreatitis Chronic pancreatitis Chronic pancreatitis is due to persistent inflammation, fibrosis, and irreversible cell damage to the pancreas, resulting in a loss of endocrine and exocrine gland function. The most common etiologies are alcohol abuse and pancreatic duct obstruction. Patients often present with recurrent epigastric abdominal pain, nausea, and features of malabsorption syndrome (diarrhea, steatorrhea, and weight loss). Chronic Pancreatitis)
• Pancreaticoduodenectomy (Whipple procedure): surgical removal of the head of the 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 the 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
• Distal pancreatectomy: removal of the body and tail of the 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
• Total pancreatectomy: surgical removal of the 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

Right and Left Flanks

Ascending and descending colon Descending colon The segment of large intestine between transverse colon and the sigmoid colon. Colon, Cecum, and Appendix: Anatomy

• Ascending and descending portions of the large intestine Large intestine The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy found in the right flank and the left flank, respectively
• Arterial supply: superior and inferior mesenteric 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
• Venous drainage: superior and inferior mesenteric 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 that join portal circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment

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

Location:

• Between T12 and L3, in the paravertebral gutter
• Their superior pole rests at the level of the 11th and 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.
• The 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 anchors them to the posterior abdominal wall Posterior abdominal wall The posterior abdominal wall is a complex musculoskeletal structure that houses the abdominal aorta, the inferior vena cava, as well as important retroperitoneal organs, like the kidneys, renal glands, pancreas, and duodenum. Posterior Abdominal Wall: Anatomy. 
• Retroperitoneal Retroperitoneal Peritoneum: Anatomy

Renal capsule Renal capsule Pyelonephritis and Perinephric Abscess:

• Holds 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 in position
• Consists of:
  • Paranephric adipose tissue Adipose tissue Adipose tissue is a specialized type of connective tissue that has both structural and highly complex metabolic functions, including energy storage, glucose homeostasis, and a multitude of endocrine capabilities. There are three types of adipose tissue, white adipose tissue, brown adipose tissue, and beige or “brite” adipose tissue, which is a transitional form. Adipose Tissue: Histology (fat)
  • Renal 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

Relations:

• Superomedially: 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
• Posteriorly:
  • Nerves: subcostal, iliohypogastric, ilioinguinal
  • 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, quadratus lumborum Quadratus lumborum Posterior Abdominal Wall: Anatomy

External characteristics:

• Superior pole
• Inferior pole
• Convex lateral surface
• Concave medial surface: renal hilum Hilum Lungs: Anatomy

Blood supply: renal arteries and veins Arteries And Veins ACES and RUSH: Resuscitation Ultrasound Protocols

Relevant procedures

• Right hemicolectomy: surgical removal of the right segment of the transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy and ascending colon Ascending colon The segment of large intestine between the cecum and the transverse colon. It passes cephalad from the cecum to the caudal surface of the right lobe of the liver where it bends sharply to the left, forming the right colic flexure. Colon, Cecum, and Appendix: Anatomy
• Left hemicolectomy: surgical removal of the left segment of the transverse colon Transverse colon The segment of large intestine between ascending colon and descending colon. It passes from the right colic flexure across the abdomen, then turns sharply at the left colonic flexure into the descending colon. Colon, Cecum, and Appendix: Anatomy and descending colon Descending colon The segment of large intestine between transverse colon and the sigmoid colon. Colon, Cecum, and Appendix: Anatomy
• Nephrectomy Nephrectomy Excision of kidney. Renal Cell Carcinoma: surgical removal of the kidney
• Kidney transplantation Kidney Transplantation The transference of a kidney from one human or animal to another. Organ Transplantation: surgical implantation Implantation Endometrial implantation of embryo, mammalian at the blastocyst stage. Fertilization and First Week of a donated kidney

Right and Left Inguinal Regions (Iliac Fossae)

Appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy

• Also referred to as vermiform appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy
• Slender, hollow, blind-ended pouch arising from the proximal cecum Cecum The blind sac or outpouching area of the large intestine that is below the entrance of the small intestine. It has a worm-like extension, the vermiform appendix. Colon, Cecum, and Appendix: Anatomy
• The appendiceal orifice is always located at the confluence of the taenia coli Taenia coli Colon, Cecum, and Appendix: Anatomy.
• On average, the appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy is approximately 9 cm long, but it can vary from 2 to 22 cm.

McBurney’s point McBurney’s point Appendicitis:

• Junction between the lateral and medial thirds of a line drawn from the anterior superior iliac spine Anterior Superior Iliac Spine Chronic Apophyseal Injury ( ASIS ASIS Chronic Apophyseal Injury) to the umbilicus
• Localized tenderness at this point is a classic sign of 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.
• Both McBurney’s and Rocky-Davis incisions for open appendectomy Open Appendectomy Appendectomy are performed through this point.

Inguinal canals

Boundaries:

• Superior: inferior edge of 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 transverse abdominal muscles
• Inferior: inguinal ligament Inguinal Ligament Femoral Region and Hernias: Anatomy (continuation of the external abdominal oblique aponeurosis)
• Anterior: aponeurosis of the abdominal 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
• Posterior: 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 and interfoveolar ligament

Course:

• The inguinal canal Inguinal canal The tunnel in the lower anterior abdominal wall through which the spermatic cord, in the male; round ligament, in the female; nerves; and vessels pass. Its internal end is at the deep inguinal ring and its external end is at the superficial inguinal ring. Inguinal Canal: Anatomy and Hernias is approximately 4 cm long, situated in the lower anterior abdominal wall Anterior abdominal wall The anterior abdominal wall is anatomically delineated as a hexagonal area defined superiorly by the xiphoid process, laterally by the midaxillary lines, and inferiorly by the pubic symphysis. Anterior Abdominal Wall: Anatomy, connecting its outer and inner layers above the inguinal ligament Inguinal Ligament Femoral Region and Hernias: Anatomy (superior anterior iliac spine Spine 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 to pubic tubercle).
• Runs from an upper lateral to an inferior medial direction.
• Inner orifice/ deep inguinal ring Deep inguinal ring Inguinal Canal: Anatomy and Hernias: evagination of the 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 (surrounding the spermatic cord Spermatic Cord Either of a pair of tubular structures formed by ductus deferens; arteries; veins; lymphatic vessels; and nerves. The spermatic cord extends from the deep inguinal ring through the inguinal canal to the testis in the scrotum. Testicles: Anatomy as the internal spermatic fascia Internal spermatic fascia Inguinal Canal: Anatomy and Hernias)
• External orifice/ superficial inguinal ring Superficial inguinal ring Inguinal Canal: Anatomy and Hernias: fissure Fissure A crack or split that extends into the dermis Generalized and Localized Rashes in the aponeurosis of the abdominal 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

Contents:

• Men: 
  • Spermatic cord Spermatic Cord Either of a pair of tubular structures formed by ductus deferens; arteries; veins; lymphatic vessels; and nerves. The spermatic cord extends from the deep inguinal ring through the inguinal canal to the testis in the scrotum. Testicles: Anatomy ( cremaster muscle Cremaster muscle Testicles: Anatomy, internal and external spermatic fasciae surrounding the vas deferens Vas Deferens The excretory duct of the testes that carries spermatozoa. It rises from the scrotum and joins the seminal vesicles to form the ejaculatory duct. Testicles: Anatomy, pampiniform plexus, lymphatic vessels Lymphatic Vessels Tubular vessels that are involved in the transport of lymph and lymphocytes. Lymphatic Drainage System: Anatomy, testicular neurovasculature, and tunica vaginalis Tunica vaginalis Testicles: Anatomy)
  • Ilioinguinal nerve Ilioinguinal nerve Inguinal Canal: Anatomy and Hernias
  • Genital branch of the genitofemoral nerve Genitofemoral nerve Inguinal Canal: Anatomy and Hernias
• Women: 
  • Round ligament Round ligament A fibromuscular band that attaches to the uterus and then passes along the broad ligament, out through the inguinal ring, and into the labium majus. Uterus, Cervix, and Fallopian Tubes: Anatomy and artery
  • Ilioinguinal nerve Ilioinguinal nerve Inguinal Canal: Anatomy and Hernias 
  • Genital branch of the genitofemoral nerve Genitofemoral nerve Inguinal Canal: Anatomy and Hernias

Descending and sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy

• Suspended by mesentery Mesentery A layer of the peritoneum which attaches the abdominal viscera to the abdominal wall and conveys their blood vessels and nerves. Peritoneum: Anatomy ( sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus mesocolon)
• Arterial supply: 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 ( sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus 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)
• Venous drainage: inferior mesenteric vein → portal vein Portal vein A short thick vein formed by union of the superior mesenteric vein and the splenic vein. Liver: Anatomy

Fallopian tubes Fallopian tubes The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The fallopian tubes receive an ovum after ovulation and help move it and/or a fertilized embryo toward the uterus via ciliated cells lining the tubes and peristaltic movements of its smooth muscle. Uterus, Cervix, and Fallopian Tubes: Anatomy

Segments:

• Uterine (intramural)
• Isthmus Isthmus Uterus, Cervix, and Fallopian Tubes: Anatomy
• Ampulla
• Infundibulum Infundibulum Uterus, Cervix, and Fallopian Tubes: Anatomy (opens into the peritoneal cavity Peritoneal Cavity The space enclosed by the peritoneum. It is divided into two portions, the greater sac and the lesser sac or omental bursa, which lies behind the stomach. The two sacs are connected by the foramen of winslow, or epiploic foramen. Peritoneum: Anatomy)

Broad ligament Broad Ligament A broad fold of peritoneum that extends from the side of the uterus to the wall of the pelvis. Uterus, Cervix, and Fallopian Tubes: Anatomy (ligamentum latum):

• Runs from the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy to the lateral pelvic wall
• Contains the fallopian tubes Fallopian tubes The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The fallopian tubes receive an ovum after ovulation and help move it and/or a fertilized embryo toward the uterus via ciliated cells lining the tubes and peristaltic movements of its smooth muscle. Uterus, Cervix, and Fallopian Tubes: Anatomy
• Segments:
  • Mesometrium Mesometrium Uterus, Cervix, and Fallopian Tubes: Anatomy (uterine part of the ligament)
  • Mesosalpinx Mesosalpinx Uterus, Cervix, and Fallopian Tubes: Anatomy (tubal part of the ligament)
  • Mesovarium Mesovarium Uterus, Cervix, and Fallopian Tubes: Anatomy (ligament to the ovary)

Blood supply:

• Arterial: ovarian and uterine 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
• Venous supply is from ovarian 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 right ovarian vein 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.
  • The left ovarian vein drains into the left renal vein Renal vein Short thick veins which return blood from the kidneys to the vena cava. Glomerular Filtration.

Relevant procedures

• Appendectomy Appendectomy Appendectomy is an invasive surgical procedure performed with the goal of resecting and extracting the vermiform appendix through either an open or a laparoscopic approach. The most common indication is acute appendicitis. Appendectomy: surgical removal of the vermiform appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy, most commonly because of 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
• Inguinal herniorrhaphy: surgical repair of inguinal hernias Inguinal Hernias An abdominal hernia with an external bulge in the groin region. It can be classified by the location of herniation. Indirect inguinal hernias occur through the internal inguinal ring. Direct inguinal hernias occur through defects in the abdominal wall (transversalis fascia) in Hesselbach’s triangle. The former type is commonly seen in children and young adults; the latter in adults. Inguinal Canal: Anatomy and Hernias; can be done laparoscopically or via an open approach (Lichtenstein technique is the most common)
• Salpingectomy: surgical removal of the fallopian tube Fallopian Tube A pair of highly specialized canals extending from the uterus to its corresponding ovary. They provide the means for ovum transport from the ovaries and they are the site of the ovum’s final maturation and fertilization. The fallopian tube consists of an interstitium, an isthmus, an ampulla, an infundibulum, and fimbriae. Its wall consists of three layers: serous, muscular, and an internal mucosal layer lined with both ciliated and secretory cells. Uterus, Cervix, and Fallopian Tubes: Anatomy, commonly performed to treat ectopic 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
• Salpingostomy: incising the fallopian tube Fallopian Tube A pair of highly specialized canals extending from the uterus to its corresponding ovary. They provide the means for ovum transport from the ovaries and they are the site of the ovum’s final maturation and fertilization. The fallopian tube consists of an interstitium, an isthmus, an ampulla, an infundibulum, and fimbriae. Its wall consists of three layers: serous, muscular, and an internal mucosal layer lined with both ciliated and secretory cells. Uterus, Cervix, and Fallopian Tubes: Anatomy open, commonly to remove an occupying lesion (ectopic 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), leaving the remainder of the tube intact
• Sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colectomy: surgical removal of a sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy, commonly performed for cancer or diverticulitis Diverticulitis Inflammation of a diverticulum or diverticula. Diverticular Disease
• Rectosigmoidectomy: surgical removal of the sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy and rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
• Descending colon Descending colon The segment of large intestine between transverse colon and the sigmoid colon. Colon, Cecum, and Appendix: Anatomy colostomy