Anatomy Tables - Peritoneal Cavity & Intestines

Osteology

Bone Structure Description Notes
pubis (N468, TG3-05, TG3-05) an angulated bone that forms the anterior part of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis; its body forms 1/5 of the acetabulum; its symphyseal surface unites with the pubis of the opposite side to form the pubic symphysis; the superior and inferior pubic rami participate in the formation of the obturator foramen
body superolateral portion of the pubis the body of the pubis forms about 1/5 of the acetabulum
pecten ridge on superior surface of the superior pubic ramus attachment point of the pectineal ligament; also called the pectineal line
ilium (N468, TG3-05, TG3-05) fan-shaped bone that forms the lateral prominence of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis
arcuate line ridge running from anteroinferior to posterosuperior on the inner surface of the ilium inferior boundary of the iliac fossa; marks the plane of transition from abdominal cavity to pelvic cavity (Latin, arucate = bowed)
sacrum (TG6-04, TG6-04)   a triangular bone that is the posterior skeletal element forming the pelvis it is formed by 5 fused vertebrae; the sacrum and two os coxae bones form the pelvis (Latin, sacrum = sacred bone)
promontory a projection of the superior part of the sacrum in an anterior direction the body of the fifth lumbar vertebra sits on the sacral promontory and articulates with it through a symphysis
iliopectineal line (N468, TG3-05, TG3-05)   the union of pectineal and arcuate lines together with the ala of the sacrum and the sacral promontory, this line (also known as the linea terminalis) marks the pelvic brim or the boundary between false pelvis above and true pelvis below

Muscles

Muscle Origin Insertion Action Innervation Artery Notes Image
diaphragm (N185, N263, TG5-33) xiphoid process, costal margin, fascia over the quadratus lumborum and psoas major mm. (lateral & medial arcuate ligaments), vertebral bodies L1-L3 central tendon of the diaphragm pushes the abdominal viscera inferiorly, increasing the volume of the thoracic cavity (inspiration) phrenic nerve (C3-C5) musculophrenic a., superior phrenic a., inferior phrenic a. left crus attaches to the L1-L2 vertebral bodies, the right crus attaches to the L1-L3 vertebral bodies
iliacus (N263, TG5-33) iliac fossa and iliac crest; ala of sacrum lesser trochanter of the femur flexes the thigh; if the thigh is fixed it flexes the pelvis on the thigh femoral nerve iliolumbar a. inserts in company with the psoas major m. via the iliopsoas tendon
psoas major (N263, TG5-33) bodies and transverse processes of lumbar vertebrae lesser trochanter of femur (with iliacus) via iliopsoas tendon flexes the thigh; flexes & laterally bends the lumbar vertebral column branches of the ventral primary rami of spinal nerves L2-L4 subcostal a., lumbar aa. the genitofemoral nerve pierces the anterior surface of the psoas major m.
psoas minor (N263, TG5-33) bodies of the T12 & L1 vertebrae iliopubic eminence at the line of junction of the ilium and the superior pubic ramus flexes & laterally bends the lumbar vertebral column branches of the ventral primary rami of spinal nerves L1-L2 lumbar aa. absent in 40% of cases
quadratus lumborum (N263, TG5-33) posterior part of the iliac crest and the iliolumbar ligament transverse processes of lumbar vertebrae 1-4 and the 12th rib laterally bends the trunk, fixes the 12th rib subcostal nerve and ventral primary rami of spinal nerves L1-L4 subcostal a., lumbar aa. the lateral arcuate ligament of the diaphragm crosses the anterior surface of the quadratus lumborum m.

Arteries

Artery Source Branches Supply to Notes
aorta, abdominal (N264, TG5-34) the continuation of the descending thoracic aorta inferior phrenic aa. (2), celiac trunk, middle suprarenal aa. (2), lumbar aa. (4 pairs), superior mesenteric a., renal aa. (2), testicular/ovarian aa. (2), inferior mesenteric a., median sacral a., common iliac aa. (2) abdominal wall; gastrointestinal tract; body below the level of the respiratory diaphragm abdominal aorta passes posterior to the diaphragm (aortic hiatus) at the level of the T12 vertebral body
appendicular (N295, TG5-13, N296, TG5-15) posterior cecal, anterior cecal or ileocolic no named branches vermiform appendix despite its variable origin, appendicular artery is nearly constant in its course posterior to the terminal part of the ileum
cecal, anterior ileocolic a. may give off the appendicular a. anterior surface of the cecum anterior cecal a. supplies the ileocecal junction (Latin, cecum = blind)
cecal, posterior ileocolic a. may give off the appendicular a. posterior surface of the cecum posterior cecal a. supplies the ileocecal junction (Latin, cecum = blind)
colic, left(N296, TG5-14) inferior mesenteric a. ascending br., descending br. descending colon left colic a. anastomoses with the middle colic a and the sigmoid a.to form part of the marginal a.
colic, middle (N296, TG5-13) superior mesenteric right br., left br. transverse colon middle colic a. anastomoses with the right colic a. and the left colic a. to form part of the marginal a.
colic, right (N295, TG5-13) superior mesenteric (or br. of) ascending br., descending br. ascending colon right colic a. anastomoses with the ileocolic a. and the middle colic a. to form part of the marginal a.
common iliac (TG3-62, TG5-29, TG5-30) abdominal aorta external iliac a., internal iliac a. pelvis, lower limb abdominal aorta bifurcates at the level of the L4 vertebral body to form the right and left common iliac aa.; the common iliac artery bifurcates anterior to the sacroiliac articulation into its terminal brs. (external iliac a. and internal iliac a.)
ileocolic (N295, TG5-13, N296, TG5-14) superior mesenteric a. colic br., anterior cecal br., posterior cecal br., appendicular a., ileal br. cecum, appendix, terminal portion of the ileum colic br. of the ileocolic a. participates in the formation of the marginal a.
inferior phrenic (TG5-32) abdominal aorta superior suprarenal aa. diaphragm, suprarenal gland inferior phrenic a. is the first abdominal branch of the aorta; it may arise from the celiac trunk (Latin, phrenic = diaphragm)
intestinal (N295, TG5-13) superior mesenteric a. arterial arches jejunum, ileum intestinal aa. are 12-15 in number and are found in the mesentery
lumbar (TG5-34) abdominal aorta anterior br., posterior br., spinal br. psoas major m., psoas minor m., quadratus lumborum m., spinal cord and vertebral column, deep back muscles the 4 lumbar arteries on each side arise from the posterior surface of the aorta at the level of vertebrae L1-L4; they course posterior to the psoas major m.
marginal (N296, TG5-14A, TG5-14B) formed by anastomoses of branches of the ileocolic a., right colic a., middle colic a., left colic a., sigmoid a. colic brs. colon an important anastomosis for the large intestine
median sacral TG5-34) abdominal aorta 5th lumbar aa. sacrum median sacral a. appears to be the continuation of the abdominal aorta in the median plane, although it is much smaller in size
mesenteric, inferior (N256, TG5-34, N295, TG5-13, N296, TG5-14, N300, N301, TG5-14, N302, TG5-28) abdominal aorta at the level of the L3 vertebral body left colic a., sigmoid aa.(2-3), superior rectal a. splenic flexure, descending colon, sigmoid colon, superior part of rectum branches of the inferior mesenteric a anastomose in the marginal artery (Greek, mesos = middle + enteron = intestine)
mesenteric, superior (N256, TG5-34, N295, TG5-13, N296, TG5-14, N300, N301, TG5-14, N302, TG5-28) abdominal aorta at the level of the lower 1/3 of the L1 vertebral body inferior pancreaticoduodenal a., middle colic a., jejunal a., ileal a., right colic a., ileocolic a. inferior part of the head of the pancreas, distal duodenum, jejunum, ileum, cecum, appendix, ascending colon, transverse colon superior mesenteric a. supplies the midgut derivatives; brs. of the superior mesenteric a. participate in formation of the marginal artery (Greek, mesos = middle + enteron = intestine)
rectal, superior (N296, TG5-14) inferior mesenteric a. two unnamed branches superior part of the rectum superior rectal a. is the continuation of the inferior mesenteric a. after the sigmoid brs. are given off; it anastomoses with the middle rectal a. and the inferior rectal a.
renal (NN 332 ,N335, TG5-34, TG5-32) abdominal aorta at the level of the upper border of the L2 vertebra inferior suprarenal a., apical segmental a., anterior br: superior anterior segmental a., middle anterior segmental a., inferior segmental a.; posterior br.: posterior segmental a. kidney, upper ureter, suprarenal gland the right renal a. is longer than the left renal artery; the right renal artery passes posterior to the inferior vena cava
sigmoid (N296, TG5-14) inferior mesenteric a. ascending br., descending br. sigmoid colon sigmoid aa. are 2-3 in number; they anastomose with the left colic a. to help form the marginal a. (Greek, sigmoid = resembles the greek letter sigma)

Veins

Vein Tributaries Drains Into Regions Drained Notes
renal, left (N332, N341, TG5-34) left ovarian/testicular v., left suprarenal v., sometime the left inferior phrenic v. inferior vena cava left ovary/testis; left ureter; left kidney; left suprarenal gland; left part of the respiratory diaphragm left renal v. crosses the abdominal aorta under the origin of the superior mesenteric a., creating a site of potential compression of the left renal vein
renal, right (N332, N341, TG5-34) multiple tributaries exit the kidney inferior vena cava right kidney right renal v. is shorter than the left renal v.
suprarenal v. (N332, TG5-34) no named tributaries left: left renal v.; right: inferior vena cava suprarenal gland left suprarenal v. is usually joined by the left inferior phrenic v.
vena cava, inferior (N265, TG5-30, TG5-34) formed by the union of the paired common iliac vv; tributaries: lumbar vv. 1-4, right ovarian/testicular v., renal vv., right suprarenal v., right inferior phrenic v., hepatic vv. right atrium all of the body below the level of the respiratory diaphragm the inferior vena cava is longer than the abdominal aorta

Nerves

Nerve Source Branches Motor Sensory Notes
aorticorenal ganglion (N318, TG8-16, TG5-39) preganglionic sympathetic via the lesser thoracic splanchnic n. brs. to the renal plexus vascular smooth muscle of the brs. of the renal aa. pain from the kidney, suprarenal gland, upper ureter a sympathetic ganglion; located above or near the origin of the renal a. from the abdominal aorta (Greek, ganglion = a knot or swelling)
celiac ganglion (N318, N319, N320, TG8-16, TG5-39) preganglionic sympathetic axons arrive via the greater thoracic splanchnic n. postganglionic sympathetic axons distribute via the celiac plexus along brs. of the celiac trunk vascular smooth muscle of the brs. of the celiac trunk pain from the stomach, liver & biliary system, spleen, upper half of the duodenum & pancreas a sympathetic ganglion; usually 2 celiac ganglia are located on the abdominal aorta at the origin of the celiac trunk; brs. of the vagal trunks pass through the celiac ganglion without synapsing (Greek, celiac = belly + ganglion = a knot or swelling)
collateral ganglia splanchnic nn. (thoracic, lumbar) plexuses to abdominal & pelvic viscera smooth muscle in blood vessels supplying the abdominopelvic viscera pain from the abdominopelvic viscera sympathetic ganglia; also known as: preaortic ganglia which include: celiac, aorticorenal, superior & inferior mesenteric; brs. of the vagal trunks pass through but do not synapse in collateral ganglia
ganglia, myenteric preganglionic parasympathetic via anterior and posterior vagal trunks (gut proximal to the left colic flexure) and pelvic splanchnic nn. (gut distal to the left colic flexure) postganglionic parasympathetic via many short fibers smooth muscle of the gut wall none minute ganglia located within the myenteric plexus; parasympathetic terminal ganglia
ganglia, preaortic (TG8-03) splanchnic nn. plexuses to abdominal and pelvic viscera vascular smooth muscle of vessels that supply abdominopelvic viscera pain from abdominopelvic viscera also known as: collateral ganglia which include the celiac ganglion, aorticorenal ganglion, superior mesenteric ganglion and inferior mesenteric ganglion; preganglionic parasympathetic axons of vagal trunk origin pass through the preaortic ganglia but do not synapse there
ganglia, submucosal of the gut preganglionic parasympathetic arrive via branches of the anterior and posterior vagal trunks (gut proximal to the left colic flexure) and pelvic splanchnic nn. (gut distal to the left colic flexure) postganglionic parasympathetic via many short fibers secretomotor to glands in the mucosa of the gut none terminal parasympathetic ganglia; parasympathetic terminal ganglia; also known as: Meissner's plexus
ganglia, sympathetic chain preganglionic sympathetic fibers arrive via white rami communicantes of ventral primary rami of spinal nerves T1-L2 postganglionic sympathetic fibers depart via gray rami communicantes to all spinal nn.; internal & external carotid nn.; cervical cardiac brs.; thoracic direct visceral brs.; greater, lesser & least thoracic splanchnic nn.; lumbar splanchnic nn.; sacral splanchnic nn. dilator pupillae, vascular smooth muscle, arrector pili muscles, sweat glands, suprarenal medulla, heart, lungs and gut pain from viscera located lateral to the vertebral bodies in the neck, thorax & abdominopelvic cavity; the ganglia plus their interconnecting fibers are also known as the sympathetic trunk; preganglionic cell bodies are located in the intermediolateral gray matter of spinal cord levels T1-L2
ganglion, inferior mesenteric (TG5-39, TG5-40) preganglionic sympathetic axons from the intermesenteric plexus and the 2nd lumbar splanchnic n. contributes to the inferior mesenteric plexus; contributes to the superior hypogastric plexus vascular smooth muscle of brs. of the inferior mesenteric a. pain from descending colon and sigmoid colon; pain from upper rectum a sympathetic ganglion; located on the abdominal aorta at the origin of the inferior mesenteric a.; may be a series of small, indistinguishable ganglia rather than a single large one
ganglion, superior mesenteric (N318, N322, TG8-16, TG5-39) preganglionic sympathetic axons from the celiac plexus contributes to the superior mesenteric and intermesenteric plexuses vascular smooth muscle of brs. of the superior mesenteric a. pain from the lower half of the pancreas and duodenum, jejunum, ileum, cecum, appendix, ascending colon and transverse colon a sympathetic ganglion; located on the abdominal aorta at the origin of the superior mesenteric a.
greater thoracic splanchnic n. (N318, N320, N323, N344, TG8-16, TG5-39) neurons in the intermediolateral cell column of spinal cord levels T5-T9; the greater thoracic splanchnic nerve appears to arise by multiple contributions from the sympathetic trunk no named branches celiac ganglion; preganglionic fibers supply the adrenal medulla which releases epinephrine and norepinephrine into the blood pain from the abdominal viscera greater thoracic splanchnic n. passes through the crus of the respiratory diaphragm; postganglionic processes from the celiac ganglion spread down the aorta and distribute with its branches; they innervate the smooth muscle of these vessels and vascular smooth muscle in the organs supplied (Greek, splanchna = viscera)
hypogastric n. (TG6-19, TG6-19) superior hypogastric plexus inferior hypogastric plexus supplies vascular smooth muscle of the pelvic viscera pain from the pelvic viscera paired; hypogastric n. lies inferior to the common iliac vessels; it contains postganglionic sympathetic axons
hypogastric plexus, inferior (TG5-40, TG5-41) hypogastric nn. and sacral splanchnic nn. (postganglionic sympathetic axons); pelvic splanchnic nn. (preganglionic parasympathetic axons from the ventral primary rami of spinal nerves S2-S4) contributes branches to: uterine/vaginal plexus, vesical plexus, prostatic plexus sympathetic: supplies vascular smooth muscle of vessels supplying the pelvic viscera; parasympathetic: supplies smooth muscle of the pelvic viscera pain from the pelvic viscera; general visceral afferent from the pelvic viscera inferior hypogastric plexus lies between the pelvic viscera and the pelvic wall (Latin, plexus = a braid)
hypogastric plexus, superior (N318, TG5-40, TG5-41, TG5-39) intermesenteric plexus and lumbar splanchnic nn. (postganglionic sympathetic axons) hypogastric nn. (right and left) vascular smooth muscle of the pelvic viscera (sympathetic) pain from the pelvic viscera; general visceral afferent from the pelvic viscera superior hypogastric plexus is the continuation of the intermesenteric plexus; it crosses the pelvic brim (Latin, plexus = a braid)
intermesenteric plexus (N318, TG5-40, TG5-41, TG8-16, TG5-39) lumbar splanchnic nn. 1 and 2 renal, testicular (or ovarian) and ureteric brs. sympathetic: smooth muscle of vessels supplying the gut distal to the left colic flexure pain from the descending colon, sigmoid colon and rectum intermesenteric plexus is continuous with the superior mesenteric plexus; it continues inferiorly as the inferior mesenteric plexus and superior hypogastric plexus; intermesenteric plexus does not carry vagal parasympathetic fibers; located anterior to the abdominal aorta between the superior and inferior mesenteric aa. (Latin, plexus = a braid)
least thoracic splanchnic n. (N318, N320, N323, N344, TG8-16, TG5-39) neurons in the intermediolateral cell column of spinal cord level T12 no named branches renal plexus pain from the kidney and suprarenal gland least thoracic splanchnic n.pass through the crus of the diaphragm; it synapses in minute ganglia located in the renal plexus (Greek, splanchna = viscera)
lesser thoracic splanchnic n. (N318, N320, N323, N344, TG8-16, TG5-39) neurons in the intermediolateral cell column of spinal cord levels T10-T11; the lesser thoracic splanchnic nerve appears to arise by multiple contributions from the sympathetic trunk no named branches aorticorenal ganglion; pain from the kidney and suprarenal gland lesser thoracic splanchnic n. passes through the crus of the respiratory diaphragm; postganglionic processes from the ganglion supply vascular smooth muscle of branches of the renal a. and suprarenal aa.; kidney and suprarenal gland (Greek, splanchna = viscera)
lumbar splanchnic nn. (N318, TG5-40, TG5-41) lumbar sympathetic ganglia L1-L4 no named branches smooth muscle of vessels that supply the abdominal and pelvic viscera pain from abdominal and pelvic viscera sympathetic nerves; there are four of these on each side; lumbar splanchnic nn. contribute to preaortic abdominal plexuses (celiac, superior mesenteric, intermesenteric, superior hypogastric) (Greek, splanchna = viscera)
mesenteric plexus, inferior (N318, N322, TG8-16, TG5-39) intermesenteric plexus multiple unnamed nn. course along the branches of the inferior mesenteric a. sympathetic: smooth muscle of the vessels supplying the descending colon, sigmoid colon and rectum pain from the descending colon, sigmoid colon and rectum inferior mesenteric plexus contains no vagal parasympathetic fibers; pelvic splanchnic n. axons join the most distal nn. of the plexus near gut wall (Greek, mes = in the middle of + enteron = intestine; Latin, plexus = a braid)
mesenteric plexus, superior (N318, N322, TG8-16, TG5-39) celiac plexus, superior mesenteric ganglion multiple unnamed nn. course along the branches of the superior mesenteric a. sympathetic: smooth muscle of vessels supplying the lower pancreas, lower duodenum, jejunum, ileum, cecum, ascending colon and most of the transverse colon; parasympathetic (vagus): smooth muscle in the gut wall of same distribution area pain & GVA of the parts of the gut named at left superior mesenteric plexus contains a mixture of vagal (preganglionic parasympathetic) axons and postganglionic sympathetic axons (Greek, mes = in the middle of + enteron = intestine; Latin, plexus = a braid)
pelvic splanchnic n. (TG6-18A, TG6-18B, TG6-19A, TG6-19B, TG5-40, TG5-41) ventral primary rami of spinal nerves S2-S4 (cell bodies are located in the lateral horn gray of the sacral spinal cord) unnamed branches contribute to the pelvic plexus (inferior hypogastric) plexus smooth muscle and glands of the gut distal to the left colic flexure; smooth muscle and glands of all pelvic viscera none parasympathetic nerves; these contain preganglionic parasympathetic axons (Greek, splanchna = viscera)
vagus n. (TG5-40, TG7-13, TG7-15, TG7-25) medulla: dorsal motor nucleus (GVE preganglionic parasympathetic); inferior ganglion (GVA); nucleus ambiguus (SVE); superior ganglion (GSA); inferior ganglion(SVA) auricular br., pharyngeal br., superior laryngeal, superior and inferior cervical cardiac brs., recurrent laryngeal n., thoracic cardiac brs., brs. to the pulmonary plexus, brs. to the esophageal plexus, anterior and posterior vagal trunks SVE: intrinsic muscles of the larynx, pharynx (except stylopharyngeus), and palate (except tensor veli palatini); GVE: smooth muscle of the respiratory tree & gut (proximal to the left colic flexure), heart; secretomotor: mucous glands of the larynx, respiratory tree, pharynx and gut; secretomotor to digestive glands GSA: skin of the external auditory meatus; GVA: viscera of head, neck, thorax & abdomen proximal to the left colic flexure; SVA: taste from the epiglottis also known as: CN X, 10th cranial nerve; the vagus n. passes through the jugular foramen to exit the posterior cranial fossa; (Latin, vagus = wanderer, so called due to its wide distribution to the body cavities)
esophageal plexus (TG5-40) right and left vagus (X) nn.; thoracic visceral brs. of the sympathetic trunk anterior and posterior vagal trunks preganglionic parasympathetic axons from the vagus n. supply smooth muscle and glands of the thoracic esophagus and abdominal gut and its derivatives proximal to the left colic flexure; postganglionic sympathetic axons from the thoracic visceral brs. supply vascular smooth muscle in the esophageal vessels vagus: GVA from the esophagus and abdominal gut proximal to the left colic flexure; thoracic visceral brs.carry pain from the esophagus during development of the gut, the stomach and esophagus rotate 90° to the right with the result that the left and right vagus nerves mix in the esophageal plexus and emerge as anterior and posterior vagal trunks (Latin, plexus = a braid)
phrenic n. (TG4-20, TG4-29) ventral primary rami of spinal nerves C3-C5 (cervical plexus) no named branches skeletal muscle of the respiratory diaphragm diaphragmatic pleura; some fibers contributed to the pericardium and to the adjacent mediastinal and costal pleurae phrenic n. crosses the anterior surface of the anterior scalene m. (Greek, phrenic = diaphragm)
femoral n. (TG3-19, TG3-20, TG3-21) lumbar plexus (ventral primary rami of spinal nerves L2-L4) anterior femoral cutaneous brs., nn. to: sartorius m., rectus femoris m., vastus lateralis m., vastus intermedius m., vastus medialis m., pectineus m. sartorius, rectus femoris, vastus lateralis, vastus intermedius, vastus medialis, pectineus skin of anterior thigh passes under inguinal ligament lateral to femoral a.
femoral cutaneous, lateral (TG3-02, TG3-03, TG3-14) lumbar plexus (ventral primary rami of spinal nerves L2-L3) anterior & posterior brs. sympathetic motor innervation to skin skin of the lateral thigh cutaneous nn. carry postganglionic sympathetic axons to skin (Latin, cutis = skin)
genitofemoral n. (TG3-02, TG3-14, TG3-68) lumbar plexus (ventral primary rami of spinal nerves L1-L2) genital br., femoral br. cremaster m. skin of the anterior scrotum/labia majora & upper medial thigh genitofemoral n. lies on the anterior surface of the psoas major in the abdomen; the genital br. passes through the deep inguinal ring and inguinal canal; brushing the thigh elicits an elevation of the testis via the cremasteric reflex
gray ramus communicans (TG1-17B) cell bodies located in the sympathetic chain ganglia none carries postganglionic sympathetic axons to the spinal nerve; spinal nerve will carry those axons peripherally to the skin, blood vessels, etc. none gray rami communicantes connect the sympathetic chain to spinal nerves at all vertebral levels (Latin, ramus = a branch)
iliohypogastric n. (TG3-03, TG3-14) lumbar plexus (ventral primary ramus of spinal nerve L1) lateral and anterior cutaneous brs. muscles of the lower abdominal wall skin of the lower abdominal wall, upper hip and upper thigh iliohypogastric n. receives a contribution from T12 in approximately 50% of cases
ilioinguinal n. (TG3-03, TG3-19) lumbar plexus (ventral primary ramus of spinal nerve L1) anterior cutaneous br. (also known as: anterior labial/scrotal n.) muscles of the lower abdominal wall skin of the lower abdominal wall and anterior scrotum/labium majus ilioinguinal n. courses through the inguinal canal and superficial inguinal ring
lumbar n. ventral primary rami of spinal nerves L1-L5 contributes to the formation of the lumbar and sacral plexuses numerous: see lumbar and sacral plexuses numerous: see lumbar and sacral plexuses lumbar nn. enter into the formation of the lumbar and sacral plexuses and do not give branches directly to muscles or skin
lumbar plexus (TG8-13) ventral primary rami of spinal nerves L1-L4 branches of the lumbar plexus: iliohypogastric n., ilioinguinal n., genitofemoral n., lateral femoral cutaneous n., femoral n., obturator n., lumbosacral trunk (considered to be part of sacral plexus), brs. to the psoas major and minor mm., branches to the quadratus lumborum m. muscles of the lower abdominal wall; cremaster m., psoas major and minor mm., quadratus lumborum m., iliacus m.; muscles of the anterior and medial thigh and hip skin of the lower abdominal wall, skin of the anterior scrotum/labium majus, skin of the anterior and medial thigh and lateral hip lumbar plexus is noted for its variable branching pattern of nerves that supply the abdominal wall (Latin, plexus = to braid, a network of nerves, blood vessels, or lymphatic vessels)
lumbosacral trunk part of the ventral primary ramus of L4 united with the ventral primary ramus of L5 no named branches; it contributes to the formation of the sacral plexus muscles of the hip and posterior thigh see sacral plexus the lumbosacral trunk is not considered to be part of the lumbar plexus (Latin, plexus = a braid, a network of nerves, blood vessels, or lymphatic vessels)
obturator n. (TG5-08, TG5-09) lumbar plexus (ventral primary rami of spinal nerves L2-L4) anterior and posterior brs. muscles of the medial thigh: adductor longus m., adductor brevis m. and adductor magnus m., gracilis m., obturator externus m. skin of the lower medial thigh obturator n. passes through the obturator canal (Latin, obturare = close, obscure)
subcostal n. (TG5-02, TG5-38) ventral primary ramus of T12 lateral cutaneous br., anterior cutaneous br. muscles of the abdominal wall skin of the anterolateral abdominal wall the subcostal n. is equivalent to a posterior intercostal n. found at higher thoracic levels (Latin, costa = rib)
white ramus communicans (TG1-17B) cell bodies located in the lateral horn gray matter of spinal cord levels T1-L2; none axons contained within white rami communicantes will synapse on postganglionic cell bodies that will ultimately innervate the skin, viscera, glands, blood vessels, etc. pain from viscera is carried back to the spinal cord through the white ramus communicans white rami communicantes connect the sympathetic chain to spinal nerves at vertebral levels T1-L2; carries preganglionic sympathetic axons (Latin, ramus = a branch)

Viscera

Organ/Part of Organ Location/Description Notes
appendix, vermiform (N273, TG5-15A, N274, TG5-15B, TG5-15C, N276) terminal portion of the cecum which has a small dead-end lumen vermiform appendix is attached to the posteroinferior surface of the cecum; it is usually located behind the cecum in the right iliac fossa; pain from the appendix projects to McBurney's point on anterior abdominal wall (1/3rd distance along and imaginary line from the anterior superior iliac spine to the umbilicus); it has a complete peritoneal covering and a small mesentery (mesoappendix) (Latin, vermiform = worm-shaped)
appendix epiploica(N273, TG5-15A, N274, TG5-15B, TG5-15C, N276) fat-filled pendants of peritoneum projecting from the visceral peritoneum on the surface of the large intestine there are many appendices epiploices on the large intestine (except the rectum) and none on the small intestine; also known as: omental appendage
ascending colon (N276, TG5-12B) part of the large intestine that is continuous with the cecum proximally and the transverse colon at the right colic (hepatic) flexure ascending colon is retroperitoneal
cecum (TG5-15A, TG5-15B) first part of the large intestine which is located in the right lower quadrant cecum is continuous with the ileum (small intestine) at the ileocecal valve; it is continuous with the ascending colon distally; it is intraperitoneal but lacks a mesentery; the vermiform appendix is attached to its posteroinferior surface (Latin, cecum = blind)
descending colon (N276, TG5-12B) part of the large intestine that is continuous with the transverse colon at the left colic (splenic) flexure and the sigmoid colon at the pelvic brim descending colon is retroperitoneal
duodenojejunal junction (N262, TG5-14, TG5-26) part of the small intestine where the duodenum is continuous with the jejunum duodenojejunal junction is located in the left upper quadrant; it is suspended by the suspensory muscle (ligament) of the duodenum; the inferior mesenteric v. passes to left side of the duodenojejunal junction
haustra (N276, TG5-12B) multiple pouches in the wall of the large intestine haustra form where the longitudinal muscle layer of the wall of the large intestine is deficient; also known as: sacculations (Latin, haustra = a machine for drawing up water)
hepatic flexure (N276, TG5-12B) junction of the ascending colon and the transverse colon hepatic flexure lies anterior to the lower part of the right kidney and inferior to the right lobe of the liver; also known as: right colic flexure
ileocecal junction(N273, TG5-15A, TG5-15B) point at which the ileum joins the cecum ileocecal valve moderates the flow of intestinal contents from the ileum into the cecum
ileocecal valve (N274, TG5-15B, N276) a valve that marks the ileocecal junction ileocecal valve is incompetent, not a sphincter; it has superior and inferior lips
ileum (N261, TG5-12B, N272, TG5-16) most distal part of the small intestine ileum is continuous with the jejunum proximally and terminates at ileocecal junction distally; it is approximately 12 feet in length; it has a thinner wall than the jejunum, lower plicae circulares than the jejunum, more fat in its mesentery than does the jejunum, more complex arterial arcades than the jejunum, shorter arteriae recta than the jejunum
intestine, large (N276, TG5-12B) part of the intestinal tract distal to the small intestine large intestine is approximately 5 feet long; parts of the large intestine are: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum; also known as: colon or large bowel
intestine, small (N261, TG5-16, TG5-12B) part of the intestinal tract between the stomach proximally and the large intestine distally small intestine is approximately 21 feet long; parts of the small intestine are: duodenum (1 foot long, mostly retroperitoneal); jejunum (8 feet long); ileum (12 feet long)
jejunum (N261, TG5-12, N272, TG5-16) part of the small intestine that is continuous with the duodenum proximally (at the duodenojejunal junction) and the ileum distally (no obvious landmark for its termination) jejunum is approximately 8 feet in length; wall of the jejunum is thicker than the wall of the ileum; plicae circulares (circular folds) are more pronounced in the jejunum than in the ileum; mesentery of the jejunum has less fat than that of the ileum; arterial arcades of the jejunum are simpler than those of the ileum; arteriae recta are longer in the jejunum than they are in the ileum
left colic flexure (N276, TG5-12B) junction of the transverse colon and descending colon left colic flexure lies anterior to the left kidney and inferior to the spleen; also known as: splenic flexure
omental appendage (N263, N276, TG5-12B) fat-filled pendants of peritoneum projecting from the visceral peritoneum on the surface of the large intestine there are many omental appendages on the large intestine (except the rectum) and none on the small intestine; also known as: appendix epiploica (Latin, omentum = the membrane which encloses the bowels)
right colic flexure (N276, TG5-12B) junction of the ascending colon and the transverse colon right colic flexure lies anterior to the lower part of the right kidney and inferior to the right lobe of the liver; also known as: hepatic flexure
sigmoid colon (N276, TG5-12B) part of the distal large intestine located within the lower left quadrant sigmoid colon is continuous proximally with the descending colon at the left pelvic brim; it is continuous distally with the rectum at the level of the 3rd sacral vertebra; it is suspended from posterior abdominal wall by the sigmoid mesocolon (Greek, sigmoid = resembles the greek letter sigma)
stomach (N261, TG5-12, TG5-18) dilated portion of the digestive system located primarily in the upper left quadrant stomach rotates during embryonic development so that the lesser curvature (originally the anterior surface) faces superiorly and to the right, the greater curvature (originally the posterior surface) faces inferiorly and to the left
teniae coli (N276, TG5-12B) band of longitudinal smooth muscle on the surface of the large intestine there are three teniae coli, named according to their position on the transverse colon: tenia omentalis (located at the line of attachment of the omental apron), tenia mesocolica (located at the line of attachment of the transverse mesocolon), tenia libera ("free" tenia - it has no mesenteric attachment obscuring it) (Latin, tenia = band or tape)
transverse colon (N276, TG5-12B) part of the large intestine located between the left and right colic flexures transverse colon is continuous proximally with the ascending colon at the right colic (hepatic) flexure; it is continuous distally with the descending colon at the left colic (splenic) flexure; it is suspended from the posterior abdominal wall by the transverse mesocolon

Peritoneal Specializations and Associated Structures

Specialization Location/Description Notes
gastrocolic ligament (N261, TG5-18) peritoneum connecting the greater curvature of the stomach with the transverse colon part of the greater omentum; derived from the dorsal mesogastrium in the embryo
gastrolienal ligament peritoneum connecting the greater curvature of stomach with the hilum of the spleen part of the greater omentum; derived from the dorsal mesogastrium in the embryo; also known as: gastrosplenic ligament
gastrophrenic ligament peritoneum connecting the fundus of the stomach to the left side of the diaphragm above the spleen part of the greater omentum; derived from the dorsal mesogastrium in the embryo
gastrosplenic ligament (N261, TG5-18) peritoneum connecting the greater curvature of stomach with the hilum of the spleen part of the greater omentum; derived from the dorsal mesogastrium in the embryo; also known as: gastrolienal ligament
greater omentum (adult dorsal mesogastrium) (TG5-12), TG5-18) apron-like specialization of peritoneum attaching along the greater curvature of the stomach subdivisions: gastrophrenic ligament, gastrosplenic ligament, gastrocolic ligament, omental apron (Latin, omentum = the membrane which encloses the bowels)
greater peritoneal sac the portion of the peritoneal cavity that is not located posterior to the stomach the lesser peritoneal sac is the only part of the peritoneal cavity that is not part of the greater peritoneal sac
hepatoduodenal ligament (TG5-18) part of the lesser omentum connecting the liver to the 1st part of duodenum hepatoduodenal ligament contains the common bile duct, proper hepatic a. and portal v.; it forms the anterior wall of the omental (epiploic) foramen
hepatogastric ligament (TG5-18) part of the lesser omentum connecting the liver to the lesser curvature of the stomach hepatogastric ligament forms the anterior wall of the lesser peritoneal sac
omental apron (N261, TG5-12) part of the greater omentum that hangs inferiorly from the transverse colon omental apron is derived from the dorsal mesogastrium during development (Latin, omentum = the membrane which encloses the bowels)
omental bursa (TG5-18) part of the peritoneal cavity located posterior to the stomach and lesser omentum omental bursa is continuous with the greater peritoneal sac at the omental (epiploic) foramen; also known as: lesser peritoneal sac
omental foramen (TG5-18) passageway between the greater peritoneal sac and the lesser peritoneal sac located posterior to the hepatoduodenal ligament; also known as: epiploic foramen
lesser omentum (adult ventral mesogastrium) (TG5-18) peritoneum stretching between the lesser curvature of the stomach and the visceral surface of the liver subdivisions of the lesser omentum are the heptogastric and hepatoduodenal ligaments; lesser peritoneal sac (omental bursa) lies posterior to the lesser omentum and stomach (Latin, omentum = the membrane which encloses the bowels)
lesser peritoneal sac (TG5-18) part of the peritoneal cavity located posterior to the stomach and lesser omentum lesser peritoneal sac is continuous with the greater peritoneal sac at the omental (epiploic) foramen; also known as: omental bursa
lienorenal ligament peritoneum that attaches the spleen to the posterior abdominal wall over the left kidney lienorenal ligament develops from the dorsal mesogastrium of the embryo; also known as: splenorenal ligament
mesentery (N295, TG5-13,N335) peritoneum connecting jejunum & ileum to posterior abdominal wall also known as: mesentery of small intestine (Greek, meso = in the middle of + enteron = intestine)
mesoappendix (N273, TG5-15) peritoneum connecting the vermiform appendix to the mesentery of the small intestine the appendix has its own mesentery which contains its blood supply - a clinically relevant detail during appendectomy
anterior cecal fold (N273, TG5-15) peritoneal fold passing from the mesentery to the anterior surface of the cecum contains the anterior cecal artery
ileocecal fold (N273, TG5-15) peritoneal fold passing from the ileum to the cecum, inferior to the ileocecal junction avascular; contains no major artery
peritoneum serous membrane lining the peritoneal cavity visceral peritoneum lies on the surfaces of the abdominal and pelvic organs; parietal peritoneum lines the inner surfaces of the walls of the abdominopelvic cavity
peritoneum, parietal (N335,N336, TG5-42, N337, TG5-43) serous membrane lining the inner surfaces of the walls of the abdominopelvic cavity peritoneum, pleura and pericardium are all serous membranes that formed from the same layer of tissue (splanchnic mesoderm) in the embryo (Greek, peritonaion = stretch around)
peritoneum, visceral (N335, N336, TG5-42, N337, TG5-43) serous membrane lying on the surfaces of the abdominal and pelvic organs visceral peritoneum is formed from the splanchnic mesoderm in the embryo (Greek, peritonaion = stretch around)
sigmoid mesocolon (N276, N296, TG5-14) peritoneum connecting the sigmoid colon to posterior abdominal wall branches of the inferior mesenteric a. approach the sigmoid colon within the sigmoid mesocolon; ascending preganglionic parasympathetic axons course through the sigmoid mesocolon in their route from the pelvis (S2,3,4) to the descending colon (Greek, sigmoid = resembles the greek letter sigma)
splenorenal ligament (N261, TG5-20) peritoneum that attaches the spleen to the posterior abdominal wall over the left kidney splenorenal ligament develops from the dorsal mesogastrium of the embryo; also known as: lienorenal ligament
transverse mesocolon (N276, N296, TG5-14) peritoneum connecting the transverse colon to the posterior abdominal wall transverse mesocolon represents the fusion of the transverse mesocolon with one layer of the greater omentum in the embryo; it forms the floor of the lesser peritoneal sac
falciform ligament (N261, TG5-12) sickle-shaped fold of peritoneum connecting liver to umbilicus contains round ligament of liver (ligament teres hepatis) (Latin and English combo, falciform = shaped like a scythe or sickle)

Joints and Ligaments

Joint Description Significance
pubic symphysis (N240, TG5-03, TG6-04) symphysis midline joint uniting the pubic bodies (Greek, symphysis = a growing togther)

Lymphatics

Structure Location Afferents from Efferents to Regions drained Notes
cisterna chyli (N266, N546, TG5-37) between the abdominal aorta and the inferior vena cava anterior to the body of the L1 or L2 vertebra right and & left lumbar trunks; possibly the intestinal trunk thoracic duct all of the body below the respiratory diaphragm; all of the abdominal and pelvic viscera cisterna chyli is an enlargement of the lower end of the thoracic duct; it occurs in about 25% of individuals
common iliac nodes (N266, N546, TG5-37) along the common iliac vessels; over the sacral promontory external iliac nodes, internal iliac nodes lumbar (lateral aortic) chain of nodes lower limb; pelvic organs, perineum, lower part of the anterior abdominal wall common iliac nodes are approximately 6 in number
external iliac nodes (N266, N546, TG5-37) along the external iliac vessels superficial inguinal nodes; deep inguinal nodes; inferior epigastric nodes common iliac nodes lower limb; external genitalia; lower part of the anterior abdominal wall external iliac nodes are 8 to 10 in number
internal iliac nodes (N266, N546, TG5-37) along the internal iliac vessels lymphatic vessels from the pelvic viscera common iliac nodes, external iliac nodes pelvis, perineum and gluteal region internal iliac nodes are 4 to 8 in number
intestinal lymphatic trunk (N266, N546, TG5-37) left side of the abdominal aorta or between the abdominal aorta and the inferior vena cava near the level of the superior mesenteric artery union of efferent lymphatic vessels from the celiac nodes and superior mesenteric nodes left lumbar trunk or the cisterna chyli/thoracic duct large and small intestines intestinal lymph trunk carries lymph that is rich in fat; drains into the left lumbar trunk (70%), cisterna chyli (25%) or right lumbar trunk (5%)
lateral aortic nodes (N266, N546, TG5-37) along the inferior vena cava and abdominal aorta from the aortic bifurcation to the aortic hiatus of the diaphragm common iliac nodes; lymphatic vessels from the posterior abdominal wall and viscera efferents form one lumbar trunk on each side lower limb; pelvic organs; perineum; anterior and posterior abdominal wall; kidney; suprarenal gland; respiratory diaphragm also known as: lumbar nodes; the intestinal trunk drains into to the left lumbar trunk; the lumbar trunks unite to form the thoracic duct/cisterna chyli
lumbar nodes (N266, N546, TG5-37) also known as: lateral aortic nodes
lumbar trunk (N266, N546, TG5-37) between the lumbar vertebral bodies and inferior vena cava (right) or aorta (left) at the upper end of the lumbar chain of nodes lumbar (lateral aortic) nodes; the intestinal trunk joins the left lumbar trunk thoracic duct/cisterna chyli left lumbar trunk - left side of the body below the respiratory diaphragm, gut; right lumbar trunk - right side of body below the diaphragm lumbar trunks unite to form the lower end of the thoracic duct; an enlargement of the lower end of the thoracic duct (called the cisterna chyli) occurs in about 25% of individuals, and when it is present, the lumbar trunks drain into it
thoracic duct (TG4-10) between the esophagus anteriorly and the thoracic vertebral bodies posteriorly formed by the union of the lumbar lymph trunks, sometimes dilated to form a cisterna chyli junction of the left subclavian v. and the left internal jugular v. all of the body and limbs below the respiratory diaphragm; the left side of the chest, left upper limb and the left side of the head and neck above the diaphragm thoracic duct is the largest lymphatic vessel; it passes through the aortic hiatus on the right side of aorta; it swings to the left side of the esophagus at the T4-T5 intervertebral disc (at the level of the sternal angle)

Clinical Terms

Term Definition
ileus an obstruction of the intestines. (Greek, eileos = intestinal colic)
Meckel's diverticulum an out-pouching of the small bowel (ileum). Present in about 2% of people and usually occurs about 2 feet before the junction with the cecum. Can be lined by stomach-type mucosa and ulcerate, perforate, or cause small bowel obstruction. This is caused by failure of the vitelline duct to obliterate during embryologic development. They are true diverticula, meaning that they affect all three muscle layers of the intestinal wall.
omphalocele herniation of abdominal viscera through umbilical and supraumbilical abdominal wall into a sac covered by peritoneum and amniotic membrane. This sac is thin and can easily rupture. Seen in neonatology. (Greek, omphal- = navel + -cele = hernia)
gastroschisis herniation of abdominal viscera through the abdominal wall 2cm lateral to the umbilicus. Unlike an omphalocele, this herniation is NOT covered by a sac. Seen in neonatology.
intestinal obstruction a blockage of the bowel lumen prohibiting the passage of material. Common symptoms include constipation and obstipation, abdominal swelling and abdominal pain. Treatment includes intravenous fluids, rest, nasogastric suction and surgery in select cases when the obstruction does not resolve with conservative management.
peritonitis inflammation of the peritoneum, a condition marked by exudations in the peritoneum of serum, fibrin, cells and pus. It is attended by abdominal pain and tenderness, constipation, nausea and vomiting, and moderate fever.
malrotation of gut abnormal or incomplete rotation of bowel that may be associated with a narrow attachment of small bowel mesentery. This permits rotation, presenting as midgut volvulus, which is a surgical emergency due to the twisting on the vascular pedicle. It is often an isolated finding, but 20% are associated with: duodenal atresia, annular pancreas, duodenal diaphragm. It typically is diagnosed in children under one month of age.
volvulus the twisting of the intestines which causes obstruction and colic. (Latin, volvo = to roll)
intussusception a telescoping of one portion of the intestine into another. This results in reduced blood supply to the affected portion of the intestine. Intussusception is seen almost exclusively in children between the ages of 5 months and 1 year. It is three times more common in boys and the exact cause is unknown. In older children, tumors and polyps can cause intussusception. The classic finding is "currant jelly stools", and is sometimes accompanied with pain, emesis, lethargy, and a tubular mass which is palpable.
colectomy surgical resection of part or all of the large intestine. This may be performed as an "open" procedure or laparoscopically. It is routinely performed for conditions such as colon cancer, diverticular disease, inflammatory bowel disease, and intestinal blockage. A total colectomy refers to removal of the entire large intestine. Hemicolectomy refers to removal of only a portion of the large intestine.
rebound tenderness when pressure is applied to the abdominal wall and then suddenly removed, extreme localized pain is felt.
bezoars concretions formed in the alimentary canal of swallowed hair, fruit, or vegetable fibers.
hypovolemia a deficiency in the amount of circulating plasma in the body
femoral nerve iatrogenic injury During open abdominal surgeries (i.e., hysterectomy), rectractor blades are used to keep the cavity open. The blade may come to rest on the femoral nerve, crushing it as it lies in the groove between the iliacus and psoas major muscles.
hiatal hernia A type of hernia that occurs when a portion of the stomach protrudes through the diaphragm (where the esophagus normally passes through). Obesity and smoking are considered risk factors. Hiatal hernia is often associated with reflux esophagitis. Symptoms include heartburn, difficulty swallowing, chest pain and belching. Treatment includes H2 antagonists, proton pump inhibitors, and antacids. (Latin, hernia = to rupture)
congenital diaphragmatic hernia A condition present at birth in which there is abnormal protrusion of abdominal contents upward through a defect in the diaphragm. This condition is treated as a surgical emergency due to interference with the infant's breathing. This compromises development of the lungs. It most commonly occurs on the left side (due to the liver's position on the right). Smaller, less serious diaphragmatic hernias may also be seen in adults. (Latin, hernia = to rupture)
abdominal aortic aneurysm (AAA) A distended and weakened area in the wall of the abdominal aorta, more common in those who suffer from atherosclerosis. The aneurysm is usually located below the renal arteries and above the aortic bifurcation. Symptoms include sudden, severe abdominal pain with radiation to the back. (Greek, aneurysm = a dilation)

The material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest & Jaye Schlesinger
Published by ILOC, Inc., New York
Copyright © 1995, unauthorized use prohibited.
The excellent editorial assistance of
Dr. Pat Tank, UAMS
is gratefully acknowledged.