Posterior Abdominal Wall PDF

Course outline Module: Time: 3hrs Outline: 1. Diaphragm 2. Posterior abdominal wall 1. Fascia 2. Muscles 3. Nerves (Somatic; Autonomic) 4. Vessels ( Arteries; veins) 3. Retroperitoneal organs 1. The suprarenal glands 2. The Kidneys 3. The ureters Objectives: At the end of this l...

Course outline Module: Time: 3hrs Outline: 1. Diaphragm 2. Posterior abdominal wall 1. Fascia 2. Muscles 3. Nerves (Somatic; Autonomic) 4. Vessels ( Arteries; veins) 3. Retroperitoneal organs 1. The suprarenal glands 2. The Kidneys 3. The ureters Objectives: At the end of this lecture, the student will be able to: 1. Define anatomy of the diaphragm 2. Describes fascia & muscles of pos. abdominal wall 3. Explains anatomy of suprarenal gland, Kidneys & Ureters 4. Mentions the neurovascular structures of post. abdominal wall 5. Evaluates the clinical considerations of each  The diaphragm; Posterior abdominal wall 1 1. DIAPHRAG is a double-domed, Mmusculotendinous partition separating the thoracic and abdominal cavities its convex superior surface faces the thoracic cavity The level of the domes of the its concave inferior varies according to: diaphragm surface faces the abdominal Phase of cavity respiration curves superiorly into right (inspiration or and expiration). left domes Posture (e.g., normally the right dome is supine or 2 higher than the left owing standing). to the presence of the liver. Size and degree Diaphra gmConsists of two parts: 1. The muscular part is situated peripherally with fibers converge radially on the trifoliate central 2 Theaponeurotic central part, hasthe. tendon: no central tendon bony attachme nts is incompletely divided into three 3 leaves is closer to the Diaphra gm is divided into three muscular part, based on the peripheral attachments: 1.Sternal part: two muscular slips attach to the posterior aspect of the xiphoid process this part is not always present. 2.Costal part: consisting of wide muscular slips attach to the internal surfaces of the inferior six costal cartilages and their adjoining ribs on each side forms the right and left domes 3.Lumbar part arising from: two aponeurotic arches, the medial and lateral arcuate ligaments, the three superior lumbar vertebrae forms right and left muscular crura 5 ascending to the central tendon. 6 The crura of the diaphragm: are musculotendinous bands that arise from: the anterior surfaces of the bodies of the superior three lumbar vertebrae the anterior longitudinal ligament the IV discs. The right crus: larger and longer than the left crus arises from the first three or four lumbar vertebrae The left crus arises from: 7 the first two or three lumbar vertebrae  The diaphragm: is also attached on each side to the medial and lateral arcuate ligaments. The medial arcuate ligament is a thickening of the fascia covering the psoas major, spanning b/n the lumbar vertebral bodies and the tip of the transverse process of L1. The lateral arcuate ligament 9 covers the quadratus Opening in the diaphragm 1 6 1. Caval opening is an aperture in the central tendon part lies at the level of the IV disc between the T8 and T9 vertebrae is located to the right of the median plane at the junction of the central tendon's right and middle leaves. is most superior of the three large diaphragmatic apertures primarily for the IVC also transmits: terminal branches of the right phrenic nerve a few lymphatic vessels on their way from the liver to the middle phrenic and mediastinal lymph nodes. 1 1 2. Esophageal is an oval opening in the muscle of the hiatus right crus of the diaphragm located at the level of the T10 vertebra is superior to and to the left of the aortic hiatus transmits: the anterior and posterior vagal trunks esophageal branches of the left 3. Aortic gastric vessels hiatus is the a few lymphatic opening vessels posterior in the diaphragm the aorta passes between the crura of the diaphragm posterior to the median arcuate ligament lies at the level of the inferior border of the T12 1 2 vertebra SMALL (minor) OPENINGS IN DIAPHRAGM Minor opening in the diaphragm include: 1. the sternocostal triangle (foramen of Morgagni ) between the sternal and costal attachments of the diaphragm. transmits: lymphatic vessels from the diaphragmatic surface of the liver the superior epigastric vessels 2.the two small apertures in each crura: the Lesser aperture of right & left crura- transmits the greater and lesser splanchnic nerve 3.The medial & lateral arcuate ligament Transmits the sympathetic trunks & the least splanchnic nerves. Blood Supply Arterial supply: The arteries of the diaphragm form a branch-like pattern on both its superior (thoracic) and inferior (abdominal) surfaces. The arteries supplying the superior surface: the pericardiacophrenic and musculophrenic arteries - branches of the internal thoracic artery the superior phrenic arteries - arising from the thoracic aorta. The arteries supplying the inferior surface the inferior phrenic arteries - the first branches of the abdominal aorta, they may arise from the celiac trunk. 1 4 1 5 Venous Drainage The veins draining of the superior surface: the pericardiacophrenic and musculophrenic veins, which empty into the internal thoracic veins on the right side, a superior phrenic vein drains into the IVC. some veins from the posterior curvature of the diaphragm drain into the azygos and hemiazygos veins The veins draining the inferior surface are: the inferior and the other,phrenic more veins. posterior branch usually joining The right the inferior phrenic vein usually left suprarenal opens The into right andtheleft IVCphrenic veins may anastomose the left inferior phrenic with each vein is usually other 1 double, open into 1 IVC Lymphatic The lymphatic plexuses drainage: on the superior and inferior surfaces of the diaphragm communicate freely The anterior and posterior diaphragmatic lymph nodes are on the superior surface of the diaphragm. Lymph from these nodes drains into: the parasternal posterior mediastinal and phrenic lymph 1 nodes. 2 Lymphatic vessels Nerve supply: The entire motor supply is from the right and left phrenic nerves each arises from the anterior rami of C3-C5 segments of the spinal cord Sensory is innervation distributed to the ipsilateral (pain and half of the diaphragm from its proprioception): inferior surface is also mostly from the phrenic nerves Peripheral parts of the diaphragm receive their sensory 13 nerve supply from the intercostal nerves ( T5 – T11) Clinical considerations 1.Hiccups: involuntary, spasmodic contractions of the diaphragm, leading to quick inhalations that are interrupted by the involuntary closure of the glottis - which checks the inflow of air and produces a characteristic sound result from irritation of afferent or efferent nerve endings or of medullary centers in the brainstem that control the muscles of respiration, particularly the diaphragm Hiccups have many causes, such as indigestion, diaphragm irritation, alcoholism, cerebral lesions, and thoracic and abdominal lesions, all which disturb the phrenic nerves 1 9 2. Referred pain from the diaphragm Pain from the diaphragm radiates to two different areas. Why? is referred to the shoulder region, the area of skin supplied by the C3 - C5 segments of the spinal cord These segments also contribute anterior rami to the phrenic nerves is more localized, being referred to the skin over the costal margins of the anterolateral abdominal wall From peripheral part 3.Congenital diaphragmatic hernia Posterolateral defect of the diaphragm is the only relatively common congenital anomaly of the diaphragm 2 0 2. POSTERIOR ABDOMINAL WALL is mainly composed of the: Five lumbar vertebrae and associated IV discs (centrally) Fascia, including the thoracolumbar fascia. Muscles 1. the psoas major and minor 2.quadratus lumborum 3.Iliacus 4.transversus abdominis muscles 5.Diaphragm, which contributes to the superior part of the posterior wall Lumbar plexus, composed of the 2 4 anterior rami of lumbar spinal nerves 1. Fascia of posterior abdominal wallabdominal The posterior wall is covered with a continuous layer of endoabdominal fascia the psoas fascia covering the psoas major muscle (psoas sheath) Medially attached to the lumbar vertebrae and is thickened superiorly to form the pelvic brim medial arcuate ligament laterally with the quadratus lumborum and 25 thoracolumbar fascia 2. Iliac Fascia Covers the iliacus muscle Medially: fuses with psoas fascia attached to iliopectineal eminence Inferiorly: passes deep to inguinal ligament & forms posterior layer of femoral sheath 2 9  The thoracolumbar fascia (TLF): diamond shaped is an extensive fascial complex attached to the vertebral column medially TL F is thin and transparent where it covers the thoracic parts of the deep muscles is thick and strong in the lumbar region. Comparable with 2 rectus sheath 7 enclosing rectus Thoracolumbar Made fasciaup of 3 layers 1. anterior layer covering the anterior surface of the quadratus lumborum attaches to the anterior surfaces of the transverse processes of the lumbar vertebrae, the iliac crest, and the 12th rib is continuous laterally with the aponeurotic origin of the transversus abdominis muscle thickens superiorly to form the lateral arcuate ligament 2 8 is adherent inferiorly to the iliolumbar ligaments 2. Posterio Extends from the 12th rib to r: the iliac crest Medially attached to spinous process of lumbar vertebrae Laterally goes to the internal oblique TL and transverse abdominis F muscles Overlies the latissimus dorsi muscle 3.Middle: with the anterior layer, encloses the quadratus lumborum muscle Medially attached to transverse process of lumbar vertebrae 2. Muscles of posterior abdominal Wall The main paired muscles include: 1. Psoas major 2. Psoas minor: Origin: T12 and L1 vertebrae Insertion: attaches to the pectineal line on the superior pubic ramus Function: weak flexor of the trunk Innervation: ventral rami of L1– L3 3 0 3. Iliacus: Absent lying along in 40% the of the lateral sides of the inferior 4. Quadratus lying adjacent to the lumborum: transverse processes of the lumbar vertebrae and lateral to superior parts of the psoas major forms a thick muscular sheet Close to the 12th rib, the lateral arcuate ligament crosses the quadratus lumborum The subcostal nerve passes posterior to this ligament and runs inferolaterally on the quadratus lumborum. 3 Branches of the 1 3 2  Lumbosacral triangle (of Marcille) Surgically most important triangle Boundaries: Medially: body of L5 Laterally: medial border of psoas major Apex: junction of medial & lateral margin Base: Ala of sacrum Floor: transverse process of L5 & iliolumbar ligament 3 6 3. NERVES OF POSTERIOR Consists of: ABDOMINAL WALL a.the somatic nervous systems b.the autonomic nervous systems a. the somatic nervous systems 1.The subcostal nerves (anterior rami of T12): arise in the thorax pass posterior to the lateral arcuate ligaments into the abdomen run inferolaterally on the anterior surface of the quadratus lumborum pass through the transversus abdominis and internal oblique muscles supply the external oblique and skin of the anterolateral abdominal wall. 2.The lumbar spinal nerves (L1-L5): pass from the spinal cord through the IV foramina inferior to the corresponding vertebrae 3 divide The upper into two or three posterior and(L1, L2 or rami anterior L3) give rise 3 to white each ramuscommunicating contains sensory and motor fibers Exist in the form of plexus known as Lumbar the posterior rami pass posteriorly to supply the muscles of 3 2  The lumbar plexus of nerves: is formed anterior to the lumbar transverse processes, within the proximal attachment of the psoas major. composed of the anterior rami of L1 - L4 nerves. 3 3 Branches of the lumbar plexus: 1. The ilioinguinal and iliohypogastric nerves (L1): arise from the anterior ramus of L1 entering the abdomen posterior to the medial arcuate ligament passing inferolaterally, anterior to the quadratus lumborum. piercing the transversus abdominis near the ASIS. the division of the L1 anterior ramus may occur as far distally as the ASIS, so that often only one nerve (L1) crosses the posterior abdominal wall instead of two 2.The genitofemoral nerve (L1, L2): into femoral and genital 3 pierces the psoas major and runs inferiorly on its 6 branches anterior surface deep to the psoas fascia 3. The lateral cutaneous nerve of the thigh (L2, inferolaterally runs L3) on the iliacus enters the thigh deep to the inguinal ligament/iliopubic tract, just medial to the ASIS supplies skin on the anterolateral surface of the thigh 4.The femoral nerve (L2-L4) emerges passes from deep tothe thelateral border of the inguinal psoas major ligament/iliopubic tract to the anterior thigh innervates the iliacus supplies the flexors of the hip and extensors of the knee. 5.The obturator nerve (L2-L4): emerges from the medial border of the psoas major 3 7 passes into the lesser pelvis 6. An accessory obturator nerve (L3, L4):almost 10% is present parallels the medial border of the psoas runs anterior to the obturator nerve crosses superior to the superior pubic ramus in close proximity to the femoral vein. 7.The lumbosacral trunk (L4, L5): passes over the ala 3 (wing) of the sacrum 8 descends into the pelvis to participate in the b. Abdominal part of autonomic nerves system (ANS) Controls the involuntary body part contains three anatomically distinct divisions: 1. Sympathetic division 2. Parasympathetic division Valgus nerve Pelvic splanchnic 1. Sympathetic innervation: several different splanchnic nerves - deliver presynaptic sympathetic to the abdominal aortic plexus and its associated sympathetic ganglia 38  Lumbar part of sympathetic chain: Gives both somatic and visceral branches Somatic branches supply lower abdominal wall & lower limb Visceral branches supply only pelvic organs Thoracic part of sympathetic chain through celiac plexus Celiac plexus gives only 39  Lumbar sympathetic trunk Enters abdomen behind medial arcuate e ligament Descends in front of lumbar vertebra Lie along medial margin of psoas Right trunk is behind IVC Left trunk along left margin of aorta Passes in front of lumbar vessel But, behind common iliac vessels Give rise to 4 ganglia Give off somatic and visceral branches Somatic branches 40 (grey rami  Sympathetic innervations viscera consists: 1. Abdominopelvic splanchnic nerves arise from the thoracic and abdominal sympathetic trunks. 2.Prevertebral sympathetic ganglia. 3.Abdominal aortic plexus and its extensions, the periarterial plexuses 1. abdominopelvic splanchnic nerves convey presynaptic sympathetic fibers to the abdominopelvic cavity arise from cell bodies in the IML (or lateral horn) of the gray matter of spinal cord segments T5 - L2 or L3 pass through the paravertebral ganglia of the trunks without Autonomic nerves of posterior abdominal wall. A. Origin and distribution of presynapatic and postsynapatic sympathetic and parasympathetic fibers, and the ganglia involved in supplying abdominal viscera are shown. B. The fibers supplying the intrinsic plexuses of abdominal viscera are demonstrated  Consists of two parts: 1. Lower thoracic splanchnic nerves arise from the thoracic part of the sympathetic trunks are the main source of presynaptic sympathetic fibers serving abdominal viscera consists of : greater – originates from T5 through T9 or T10; lesser - from T10 & T11; least from the T12 level 2. Lumbar splanchnic nerves: from the lumbar part of the sympathetic trunks Medially, the lumbar sympathetic trunks: give off three to four lumbar splanchnic nerves, which pass to: intermesenteric plexus inferior mesenteric plexus superior hypogastric plexuses conveying presynaptic sympathetic fibers to the associated prevertebral ganglia of those plexuses. 13 5 Parasympathetic Innervation 3. Abdominal (para-aortic) autonomic plexuses and their extensions, the periarterial plexuses are nerve networks consisting of both sympathetic and parasympathetic fibers surround the abdominal aorta and its major branches These includes: 1.The celiac plexus - surround the root of the celiac trunk contains irregular right and left celiac ganglia ≈ 2 cm long unite superior and inferior to the celiac trunk the parasympathetic root is a branch of the posterior vagal trunk sympathetic roots of the plexus are the greater and lesser splanchnic nerves. 2.The superior mesenteric plexus and ganglion or ganglia 3. The inferior mesenteric plexus surrounds the inferior mesenteric artery gives offshoots to its branches receives a medial root from the intermesenteric plexus; lateral roots from the lumbar ganglia of the sympathetic trunks an inferior mesenteric ganglion may also appear just inferior to the root of the IMA 4.The intermesenteric plexus is part of the aortic plexus of 5. The superior hypogastric plexus is continuous with the intermesenteric plexus and the inferior mesenteric plexus lies anterior to the inferior part of the abdominal aorta at its bifurcation supplies ureteric and testicular plexuses and a plexus on each common iliac artery. right and left hypogastric nerves join the superior hypogastric plexus to the inferior hypogastric plexus 6.The inferior Figure: Autonomic nerves of posterior abdominal wall. A. Origin and distribution of presynapatic and postsynapatic sympathetic and parasympathetic fibers, and the ganglia involved in supplying abdominal viscera are shown. B. The fibers supplying the intrinsic plexuses of abdominal viscera are demonstrated Sympathetic innervation is Vasomotor Motor to sphincters Inhibitory to peristalsis Carry sensory fibres for all viscera 50 2. Parasympathetic division Receive fibres from both vagal trunks Both trunks contain fibres from right and left vagus nerves Enter prevertebral ganglia/plexus pass through without synapsy Supply viscera, gut is supplied only upto proximal 2/3 of transverse colon Parasympathetic innervation: Stimulates peristalsis Inhibitory to sphincters Secretomotor to the gut and its glands 51 Vessels o f po sterior abdo minal wall The major neurovascular bundle of the inferior trunk Includes : the abdominal aorta and its branches the inferior vena cava and its tributaries 5 2 Abdominal is ≈ 13 cm in length & 2 cm aorta width begins at the aortic hiatus in the diaphragm≈ 2.5 cm superior to transpyloric plane ends at the level of the L4 by dividing into the right and left common iliac arteries. Relations of abdominal aorta Anterior relations -from superior to inferior: celiac plexus and ganglion body of the pancreas and 5 1 splenic vein  The abdominal aorta Posteriorly: the bodies of the T12-L4 vertebrae the left lumbar veins pass posterior to the aorta to reach the IVC On the right, the aorta is related to the azygos vein cisterna chyi thoracic duct right crus of the diaphragm right celiac ganglion On the left the aorta is related to: the left crus of the diaphragm and the left celiac ganglion 5 4 Branches of the abdominal aorta: as arising may be described and coursing in three “vascular planes” can be classified as being visceral or parietal and paired or unpaired Paired parietal branches of the aorta serve the diaphragm and posterior abdominal wall. The median sacral artery, an unpaired parietal branch, may be said to occupy a fourth (posterior) plane: because it arises from 5 5 the posterior aspect of 5 6 5 7 5 8 Pulsations of aorta and abdominal aortic aneurysm Because the aorta lies posterior to the pancreas and stomach, a tumor of these organs may transmit pulsations of the aorta that could be mistaken for an abdominal aortic aneurysm, a localized enlargement of the aorta Deep palpation of the mid - abdomen can detect an aneurysm, which usually results from a congenital or acquired weakness of the arterial wall Pulsations of a large aneurysm can be detected to the left of the midline the pulsatile mass can be moved easily from side to side 5 9 6 0 Veins of posterior abdominal wall are inferior venacava and its tributaries The inferior venacava the largest vein in the body has no valves except for a variable, non- functional one at its orifice in the right atrium returns poorly oxygenated blood from the lower part of the body Blood from the abdominal viscera passes through the portal venous system and the liver before entering the IVC via the hepatic veins 6 1 The inferior vena cava (IVC) anterior to the L5 vertebra by the begins union of the common iliac veins. The union occurs: ≈2.5 cm to the right of the median plane inferior to the aortic bifurcation posterior to the proximal part of the right common iliac artery ascends on the right side of the bodies of the L3 - L5 vertebrae and on the right psoas major to the right of the aorta. the overall length of the IVC is 7 cm greater than that of 6 the abdominal aorta 2 6 3 The tributaries of the IVC correspond to: the paired visceral and parietal branches of the abdominal aorta. The veins that correspond to the unpaired visceral branches of the aorta are instead tributaries of the hepatic portal vein The branches corresponding to the paired visceral branches of the abdominal aorta include: the right suprarenal vein the right and left renal veins because the right they are tributaries gonadal (testicular of or the left vein. ovarian) renal vein. 6 The left suprarenal and gonadal veins drain indirectly 2 into the IVC 6 5 LYMPHATIC VESSELS AND LYMPH NODES 6 6 Posterior The iliopsoas muscle has Abdominal Pain clinically important extensive, relations to: the kidneys Ureters Cecum Appendix pancreas, lumbar lymph sigmoid colon and nerves of the nodes, abdominal posterior wall.any of these When diseased, structures movement is of iliopsoas usually causes the pain. intra- When inflammation abdominal is iliopsoas suspected, test theis performed. The person is asked to lie unaffected on the side and thigh extend onthe the affected side the resistance of the against han examiner's 6 d 7 Thank You!