Posterior Abdominal Wall

Gross Anatomy


Posterior Abdominal Wall, Diaphragm


Anatomy Tables for Today's Topic

Bones of the Posterior Abdominal Wall
Muscles of the Posterior Abdominal Wall
Nerves of the Posterior Abdominal Wall
Arteries
Veins
Lymphatics

Bones of the Posterior Abdominal Wall

Bone Structure Description Notes
ilium fan-shaped bone that forms the lateral prominence of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis
iliac fossa broad depression on the medial surface of the ilium iliac fossa is part of the false (greater) pelvis
vertebra one of a series of irregular bones that form the spine a vertebra has two parts: the vertebral body and the vertebral arch; there are 33 vertebrae total: 7 cervical, 12 thoracic, 5 lumbar, 5 fused to form the sacrum, 4 coccygeal; features of a typical vertebra include: body, pedicles, transverse processes, laminae, articular processes, spinous process
femur   the bone of the thigh the femur is the longest and strongest bone in the body
lesser trochanter a large process that projects from the posteromedial surface of the femur just distal to neck it is the insertion site of the common tendon of the psoas major and iliacus mm. (iliopsoas m.)

Muscles of the Posterior Abdominal Wall

Muscle Origin Insertion Action Innervation Artery Notes
iliacus 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
iliopsoas iliac fossa; bodies and transverse processes of lumbar vertebrae lesser trochanter of the femur flexes the thigh; flexes and laterally bends the lumbar vertebral column branches of the ventral primary rami of spinal nerves L2-L4; branches of the femoral nerve iliolumbar a. a combination of the iliacus and psoas major mm.
psoas major 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 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 rams of spinal nerves L1-L2 lumbar aa. absent in 40% of cases
quadratus lumborum 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.
diaphragm 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

Nerves of the Posterior Abdominal Wall

Nerve Source Branches Motor Sensory Notes
subcostal n. 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
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 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
lumbosacral plexus ventral primary rami of spinal nerves L4-S4 branches of the lumbosacral 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., superior & inferior gluteal nn., n. to the obturator internus m., n. to the quadratus femoris m., sciatic n., n. to the piriformis m., posterior femoral cutaneous n., pudendal n., n. to the pelvic diaphragm, pelvic splanchnic nn. 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, muscles of the pelvic & urogenital diaphragm, posterior hip, posterior thigh, leg and foot skin of the lower abdominal wall, skin of the anterior scrotum/labium majus, skin of the anterior and medial thigh and lateral hip' skin of the perineum, posterior thigh, leg and foot also known as: lumbar & sacral plexuses
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
femoral n. 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 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
genitofemoral n. 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
obturator n. 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
splanchnic, thoracic neurons in intermediolateral cell column of spinal levels T5-T12; nerves appear to arise by multiple contributions from sympathetic trunk greater thoracic splanchnic (formed by union of brs. emerging from ganglia T5-T9); lesser thoracic splanchnic (formed by union of brs. emerging from ganglia T10-T11); least thoracic splanchnic (formed by union of brs. emerging from ganglion T12) to pre-aortic or prevertebral ganglia in abdomen; postganglionic processes from prevertebral ganglia supply smooth muscles of vessels; preganglionic fibers supply the adrenal medulla which releases epinephrine and norepinephrine pain from abdominal viscera pass through crura of diaphragm; greater thoracic splanchnic synapses in celiac & superior mesenteric ganglia; lesser thoracic splanchnic synapses in aorticorenal ganglion; least thoracic splanchnic synapses in renal plexus
splanchnic, greater thoracic neurons in the intermediolateral cell column of spinal cord levels T5-T9; the greater thoracic splanchnic nerve arises 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 vascular smooth muscle of these vessels and the organs supplied
splanchnic, least thoracic 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. passes through the crus of the diaphragm; it synapses in minute ganglia located in the renal plexus
splanchnic, lesser thoracic neurons in the intermediolateral cell column of spinal cord levels T10-T11; the lesser thoracic splanchnic nerve arises 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
vagus n. 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; vagus means "wanderer" in reference to its extensive distribution to the body cavities
aorticorenal ganglion 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
celiac ganglion 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
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
esophageal plexus 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
preaortic ganglia white rami communicantes of sympathetic trunk to splanchnic nn. plexuses to abdominal & pelvic viscera vascular smooth muscle of vessels to abdominopelvic viscera pain from abdominopelvic viscera also known as: collateral ganglia, which include: celiac, aorticorenal, superior & inferior mesenteric; brs. of vagal trunks pass through but do not synapse
hypogastric plexus, inferior 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
hypogastric plexus, superior 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
intermesenteric plexus 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.
lumbar splanchnic nn. 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)
mesenteric plexus, inferior 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
mesenteric plexus, superior 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
myenteric ganglia 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
myenteric plexus 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 parasympathetic terminal ganglia are located here; also known as: Auerbach's plexus
pelvic splanchnic n. 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
renal plexus intermesenteric plexus, aorticorenal ganglion, least thoracic splanchnic n. unnamed branches course along the renal vessels sympathetic: smooth muscle of the blood vessels supplying the kidney, renal pelvis and upper ureter; parasympathetic: smooth muscle of the renal pelvis and upper ureter pain from the kidney, renal pelvis and upper ureter renal plexus contains postganglionic sympathetic axons and preganglionic parasympathetic axons (parasympathetic axons are of vagal origin)
sacral splanchnic n. sacral sympathetic ganglia unnamed branches contribute to the pelvic plexus (inferior hypogastric) plexus vascular smooth muscle of the pelvic viscera pain from the pelvic viscera sacral splanchnic nn. contain both preganglionic and postganglionic sympathetic nerve fibers with postganglionic fibers predominating in number
submucosal ganglia 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

Arteries

Artery Source Branches Supply to Notes
aorta, abdominal 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
lumbar 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.
subcostal descending thoracic aorta spinal br., collateral br., lateral cutaneous br. vertebrae, spinal cord; muscles, skin & fascia of the upper abdominal wall subcostal a. is equivalent to a posterior intercostal a., but is named subcostal because it courses inferior to the 12th rib

Veins

Vein Tributaries Drains Into Regions Drained Notes
ascending lumbar v. lumbar vv. 1-4 right: azygos v.; left: hemiazygos v. posterior abdominal wall ascending lumbar v. connects adjacent lumbar vv.
azygos v. formed by the union of the ascending lumbar v. and the subcostal v.; tributaries: posterior intercostal vv. 11-2 (right superior intercostal), hemiazygos v., accessory hemiazygos v., esophageal v., right bronchial v. posterior surface of the superior vena cava lateral and posterior walls of the abdomen and chest; esophagus; bronchial tree may connect with the inferior vena cava; arch of azygos passes superior to the root of the lung
hemiazygos v. formed by the joining of the left ascending lumbar v. and the left subcostal v.; tributaries: left posterior intercostal vv. 8 or 9-11; esophageal vv. azygos v. inferior levels of the left posterolateral chest wall the azygos system is variable, and levels drained by the hemiazygos v. may vary
vena cava, inferior 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

Lymphatics

Structure Location Afferents from Efferents to Regions drained Notes
cisterna chyli 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 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 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 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 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 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 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: lateral aortic nodes; the intestinal trunk drains into to the left lumbar trunk; the lumbar trunks unite to form the thoracic duct/cisterna chyli
lumbar trunk 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 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)


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Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of these tables has been edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2005, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.