Comprehensive Anatomy of the Abdomen, Pelvis, and Perineum

Practice vocabulary flashcards covering the major anatomical structures, neurovascular pathways, clinical correlations, and embryological landmarks of the abdominal aorta, abdominopelvic cavity, viscera, and perineum.

Celiac Trunk

The major anterior branch of the abdominal aorta that arises just below the aortic aperture of the diaphragm to provide arterial supply to foregut derivatives.

Superior Mesenteric Artery

The unpaired visceral branch arising from the anterior surface of the abdominal aorta that provides arterial blood supply to the midgut derivatives.

Inferior Mesenteric Artery

The unpaired anterior branch of the abdominal aorta that supplies blood to the hindgut derivatives, including the left third of the transverse colon down through the upper anal canal.

Triradiate Cartilage

The Y-shaped cartilaginous epiphyseal plate in children that joins the ilium, ischium, and pubis within the acetabulum prior to complete fusion.

Pelvic Diaphragm

The muscular partition separating the pelvic cavity from the perineum, formed primarily by the levator ani and coccygeus muscles.

Puborectalis

The component of the levator ani muscle that forms a muscular sling (rectal sling) around the anorectal junction, creating an $80^\text{o}\text{–}90^\text{o}$ angle essential for maintaining fecal continence.

Bulbs of the Vestibule

Paired erectile venous plexuses in the female vestibule covered by the bulbospongiosus muscles, homologous to the bulb of the penis.

Suspensory Ligament of the Ovary

A peritoneal fold extending from the ovary to the lateral abdominal and pelvic wall that conducts the ovarian artery and ovarian vein.

Ampulla-Isthmic Junction

The specific anatomical portion of the fallopian tube that serves as the normal site of ovum fertilization.

Broad Ligament

A wide peritoneal fold divided into the mesometrium (covering the uterus), mesosalpinx (suspending the fallopian tubes), and mesovarium (suspending the ovaries).

Incompetent Internal Os

A pathological condition of the cervix characterized by premature opening of the internal os leading to habitual abortion prior to the $3\text{rd}$ month; managed surgically with McDonald or Shirodkar cerclage.

Uterine Leiomyomas

Estrogen-sensitive benign smooth muscle tumors (fibroids) of the myometrium that can enlarge during pregnancy and cause delivery obstruction.

Endometriosis

The ectopic growth of endometrial tissue outside the uterus that breaks down and bleeds cyclically under estrogen influence, affecting $5\text{–}10\%$ of all women and $30\text{–}50\%$ of infertility patients.

Stratum Basale (Endometrium)

The deep, non-shedding, $1\,\text{mm}$ layer of the uterine endometrium from which the functional layer (stratum compactum and stratum spongiosum) regenerates following menstruation.

Corpus Luteum

An endocrine structure formed from a ruptured graafian follicle following ovulation that secretes large quantities of progesterone and estradiol during the luteal (secretory) phase.

Membranous Urethra

The short segment of the male urethra traversing the urogenital diaphragm; highly vulnerable to rupture because it is fixed and relatively immobile.

Seminal Vesicles

Convoluted accessory sex glands located posterior to the bladder that produce an alkaline secretion ($\text{pH } 7.29$) containing fructose to nourish spermatozoa.

Cremaster Muscle

The muscular covering of the spermatic cord formed by the caudal fibers of the internal abdominal oblique muscle and innervated by the genital branch of the genitofemoral nerve.

Rectus Sheath

A fibrous sheath formed by the aponeuroses of the external oblique, internal oblique, and transversus abdominis that envelops the rectus abdominis and pyramidalis muscles.

Direct Inguinal Hernia

An acquired hernia protruding medial to the inferior epigastric vessels directly through Hesselbach's triangle; presents with a low risk of strangulation and is most common in men over $40$ years of age.

Indirect Inguinal Hernia

A congenital or acquired hernia traversing the deep inguinal ring lateral to the inferior epigastric vessels and traveling through the full length of the inguinal canal inside the spermatic cord; carries a high risk of strangulation.

Epiploic Foramen (Omental Foramen)

The communication between the greater peritoneal sac and the lesser sac (omental bursa) located posterior to the hepatoduodenal ligament; a potential site for internal herniation.

Pouch of Morison

The right subhepatic space situated between the liver and the right kidney, serving as a frequent gravity-dependent site of intraperitoneal fluid accumulation in supine patients.

Rectouterine Pouch of Douglas

The deepest peritoneal recess in the female pelvic cavity, located between the rectum and the posterior wall of the uterus; a primary site for fluid accumulation during pelvic inflammatory disease.

Achalasia

A neuromotor disorder of the lower esophageal sphincter caused by a deficiency of ganglion cells in the myenteric plexus of Auerbach, characterized by aperistalsis, elevated sphincter pressure, and dysphagia for solids and liquids.

Barrett's Esophagus

Metaplastic replacement of the stratified squamous epithelium of the lower esophagus by simple columnar epithelium resulting from chronic acid exposure in GERD.

Hypertrophic Pyloric Stenosis

Progressive muscular hypertrophy of the circular fibers in the pyloric sphincter in male infants, causing projectile non-bilious vomiting and an olive-sized mass palpable at the right costal margin.

Parietal Cells

Acid-secreting epithelial cells found in the gastric body and fundic glands that synthesize hydrochloric acid ($\text{HCl}$) and intrinsic factor required for vitamin $B_{12}$ absorption in the ileum.

Chief Cells

Enzyme-producing gastric gland cells that synthesize and secrete pepsinogen, a zymogen activated by stomach $\text{HCl}$ into protein-digesting pepsin.

Hepatopancreatic Ampulla of Vater

The dilated chamber formed by the union of the common bile duct and the main pancreatic duct, which opens into the descending duodenum through the major duodenal papilla under control of the sphincter of Oddi.

Duodenal Atresia

Congenital complete luminal obstruction of the duodenum due to failure of recanalization, associated with Trisomy 21 and presenting with polyhydramnios, bilious vomiting, and the "double bubble sign" on radiographs.

Brunner's Glands

Branched submucosal glands located exclusively in the duodenum that produce an alkaline secretion to protect the mucosa from acidic chyme and maintain an optimal $\text{pH}$ for pancreatic enzymes.

Peyer's Patches

Large aggregated lymphoid follicles situated within the lamina propria and submucosa of the ileum that participate in immune surveillance.

Meckel's Diverticulum

A congenital ileal out-pocketing caused by persistence of the vitelline (omphalomesenteric) duct, located within $50\text{–}75\,\text{cm}$ of the ileocecal valve and described by the Rule of 2's.

Teniae Coli

Three distinct longitudinal ribbons of smooth muscle running along the exterior of the colon that are shorter than the bowel wall, creating sack-like pockets known as haustra.

McBurney's Point

The surface landmark located at the junction of the lateral third and medial two-thirds of a line connecting the umbilicus to the right anterior superior iliac spine, indicating the anatomical base of the vermiform appendix.

Pectinate Line

The serrated boundary formed by the lower limits of the anal valves, demarcating the junction between the hindgut-derived upper anal canal and the proctodeum-derived lower anal canal.

Internal Hemorrhoids

Prolapsed varicosities of the superior rectal veins located above the pectinate line; supplied by visceral/autonomic innervation and characterized by painless bleeding.

External Hemorrhoids

Thrombosed subcutaneous veins of the external rectal venous plexus located below the pectinate line; supplied by somatic branches of the pudendal nerve and characterized by exquisite pain.

Hirschsprung's Disease

Congenital megacolon caused by the failure of neural crest cells to migrate into the distal bowel, resulting in an absence of ganglion cells in Meissner's and Auerbach's plexuses.

Glisson's Triad (Portal Triad)

The anatomical grouping located at the periphery of hepatic lobules consisting of a portal venule branch, a hepatic arteriole branch, and a bile ductule.

Space of Disse

The perisinusoidal space located between hepatic sinusoidal endothelial cells and hepatocytes, housing fat-storing Ito (stellate) cells.

Caput Medusae

Prominent subcutaneous tortuous veins radiating from the umbilicus, formed when portal hypertension forces blood retrograde through paraumbilical veins into systemic abdominal wall veins.

Cholelithiasis

The presence of gallstones formed by an imbalance between cholesterol and bile salt concentrations; classic risk factors are summarized by the "5 Fs" (Female, Fertile, Forty/Fifty, Full-figured, Fair).

Islets of Langerhans

Microscopic endocrine clusters in the pancreas comprising alpha cells (secreting glucagon), beta cells (secreting insulin), and delta cells (secreting somatostatin).

Polycystic Kidney Disease

A genetic renal disorder characterized by the progressive development and bilateral enlargement of numerous fluid-filled cysts, culminating in destruction of the functional renal parenchyma.

Horseshoe Kidney

A congenital malformation in which the lower poles of both kidneys fuse across the midline during development, with superior migration halted at the level of the inferior mesenteric artery.

Zona Glomerulosa

The outermost zone of the adrenal cortex regulated by pituitary ACTH that synthesizes mineralocorticoids, primarily aldosterone, to control electrolyte and fluid balance.

Zona Fasciculata

The intermediate and thickest layer of the adrenal cortex that synthesizes glucocorticoids, primarily cortisol, to regulate carbohydrate, lipid, and protein metabolism.

Zona Reticularis

The innermost layer of the adrenal cortex responsible for producing small amounts of sex steroids (androgens).

Adrenal Medulla

The inner core of the suprarenal gland, directly innervated by sympathetic preganglionic fibers to synthesize and release catecholamines (adrenaline/epinephrine and noradrenaline/norepinephrine).

Iliopsoas Muscle

A powerful compound muscle formed by the merger of the psoas major and iliacus that inserts onto the lesser trochanter of the femur, acting as the primary flexor of the hip joint.