part of the trunk that lies between the thorax and pelvis located between diaphragm and pelvic brim diaphragm forms the roof no floor, continuous with pelvic cavity • 5 lumbar vertebrae • intervertebral discs • lower ribs • iliac bone • muscles organs of digestive system parts of urogenital system spleen suprarenal glands part of autonomic plexuses peritoneum extent from osteocartilagenous thoracic cage to the pelvis form lumbar vertebra to linea alba subdivisions anterio-lateral abdominal wall posterior abdominal wall Posterior abdominal wall: - Composed of 5 lumbar vertebrae & IV discs, muscles, fascia, lumbar plexus, fat, nerves, LN & lymphatic vessels - lumbar vertebrae is central prominence in posterior wall, creating paravertebral gutters (narrow groove) - Most posterior (kidney & surrounding fat) vertebral column (lumbar) lower abdominal aorta anterior structure (superior mesenteric artery, duodenum, pancreas & left renal vein) anterior abdominal wall Fascia: 2 layers of endoabdominal fascias (lie between parietal peritoneum & muscle) cover post. abdominal wall; these fascia are continuous with transversalis fascia that lines transverse abdominal muscle 1) psoas fascia - covers psoas major, attached medially to lumbar vertebrae & pelvic brim -thickens superiorly to form MEDIAL arcuate ligament -fuses laterally with quadratus lumborum(QL) & thoracolumbar fascia -continous with iliac fascia covering iliacus and fascia covering QL 2) thoracolumbar fascia - extensive fascia attached to vertebral column medially( thin ) -have anterior , middle & posterior layers with muscles enclosed between them - not attached to external oblique; but atteched to latissimus dorsi, internal oblique and transverse abdominis -posterior, middle layers( thicker becoz in the lumbar region) enclose deep back muscles (erector spinae) and have bony support than rectus sheath -anterior layer( thin bcoz not in lumbar region) quadratus lumborum fascia that continues laterally with aponeurotic origin of transverse abdominal muscle, thickens superiorly to form LATERAL arcuate ligaments sand adherent inferiorly to iliolumbar ligament muscles: major muscles are psoas major (inf + lat); iliacus (lying along lateral sides of inferior part of psoas major); quadratus lumborum (lying adjacent to transverse processes of lumbar vertebrae & lateral to superior part of psoas major) clinical application: iliopsoas are related to kidney, ureter, cecum, appendix, sigmoid colon, pancreas, lumbar LN and nerves of POST abdominal wall. Thus, when these structure are disease (adenocarcinoma of pancreas, appendicitis), movement of iliopsoas causes pain. Do iliopsoas test :1)lie on unaffected part & extend thigh on affected side against examiner’s hand positive sign when pain is elicited( right psoas sign indicates inflamed appendix) nerves: subcostal( ext oblique, skin of anterolateral wall); lumbar plexus, L1-L4( femoral, obturator, lumboacral trunk, ilioinguinal & iliohypogastric, genitofemoral nerve, lateral cut n of thigh, accessory obturator nerve-10%) Branches of ABD aorta: Vascular class Distribution plane Anterior Unpaired Alimentary tract 1 midline visceral (branch to SMA- L1, IMA- L3, Vessels of POST celiac artery-T12) abd wall abdominal aorta 2 lateral Paired Urogenital & visceral endocrine organ (begins in aortic (branch to hiatus in suprarenal- L1, diaphragm at T12 renal- L1, and ends at L4 testicular/ovarian by divide into rt artery-L2) & lt common POST + Paired Diaphragm ( iliac artey) 3 lateral parietal subcostal-L2, (segmental) inferior phrenic- T12, lumbar-L1 to L4) boundaries Rt.& Lt.costal margin, xiphoid process iliac crest, ASIS, symphysis pubis vertical line through ASIS surface anatomy median vertical fibrous line joining curved line, xiphoid process to symphysis pubis ( wider above the umbilicus ) convex laterally extending from 9th costal cartilage to pubic tubercle, indicating lateral boarder of rectus abdominis muscle xiphoid process Umbilicus • site of attachment of umbilical cord linea alba • location variable, between L 3 – L4 • mid way between xiphoid process and symphysis pubis • dermatone distribution – T 10 linea semilunaris symphysis pubis surface anatomy To describe location of the viscera (in general) location of pain, swelling, incisions etc divide the abdomen into 9 regions by pairs of vertical and horizontal planes vertical planes connecting midclavicular and midinguinal points *** horizontal planes transpyloric plane / subcostal plane transtubercular plane *** midway between suprasternal notch & symphysis pubis midway between umbilicus & xyphoid process Generally passes through • the tip of 9thcostal cartilage • fundus of the gall bladder • pylorus of the stomach • portal vein • neck of the pancreas • DJ junction • 1st lumbar vertebra • SMA • hila of the kidneys • at this point linea semilunaris crosses the costal margin others alternate method of dividing abdomen two lines / four regions other planes in the abdomen intercristal plane regions of abdomen RHC liver , gall bladder epigastrium stomach, pancreas, left lobe of liver LHC spleen, tail of pancreas, fundus of stomach Rt. lumbar right kidney, ascending colon umbilical coils of small intestine Lt. lumbar left kidney, descending colon SPA Bladder RIF caecum, appendix LIF sigmoid colon LIVER 5th rib 5th ICS • most of the bulk lies on right side • under cover of lower ribs • RHC, epigastrium, LHC • dome 5th. rib Rt. / 5th. ICS Lt. • not palpable GALL BLADDER fundus tip of the 9th. right costal cartilage on trans-pyloric plane SPLEEN LHC • related to 9, 10, 11 ribs ( long axis - 10 th rib ) • characteristic notch ( anterior border ) PANCREAS related to transpyloric plane • Head - to the right and below • Neck - on the plane • Body and tail - to the Lt. and above * KIDNEYS • right kidney lies lower than left • trans-pyloric plane passes through both hila STOMACH • epigastrium, LHC, umbilical region • fixed at 2 points • OG junction left to the XS joint ( T- 11 ) • pyloroduodenal junction right to the midline (L- 1) CAECUM & APPENDIX ( in RIF ) McBurney’s point base of the appendix umbilicus ASIS surface anatomy layers of abdominal wall Skin Fascia Muscles of the anterior abdominal wall the rectus sheath Fascia transversalis Extraperitoneal fat Peritoneum thinner skin compared to the back natural lines of cleavage run almost horizontally around the trunk incision along the cleavage line will heal with a narrow scar cutaneous nerve supply derived from anterior rami of the 7th through the 12th thoracic nerve and first lumbar nerve Dermatone “area of skin supplied by a single spinal nerve” epigastrium T 7 umbilicus T 10 symphysis pubic L1 ASIS DERMATONE DISTRIBUTION OF ANTERIOR ABDOMINAL WALL superficial fascia deep fascia ( very thin ) superficial fascia - divided into two layers fatty layer ( Camper’s fascia ) merge with subcutaneous tissue of the body membranous layer ( fascia Scarpa ) continuous with perineal fascia ( Colle’s fascia) Superficial veins superficial network of venous plexus radiate out from the umbilicus above umbilicus, - drain into axillary vein via lateral thoracic vein below umbilicus, - drain into femoral vein via superficial epigastric vein membranous layer ( fascia Scarpa ) - more prominent in lower half of abdomen - fuse with fascia Lata of thigh below the inguinal ligament - continuous with superficial fascia of perineum ( Colle’s fascia ), fascia investing penis, scrotum and labia majora - in the perineum, attached to the perineal body, posterior margin of perineal membrane and laterally to the rami of pubis and ischium Scarpa’s fascia P bulbous urethra clinical application - rupture of the bulbous urethra - extravasated urine is collected deep to Scarpa’s fascia external oblique muscle internal oblique muscle transversus abdominis muscle rectus abdominis muscle muscle origin insertion external lower 8 ribs xiphoid process, linea alba, oblique pubic crest, pubic tubercle, iliac crest internal lumbar fascia, iliac crest, lower 3 ribs and costal cartilages, oblique lateral xiphoid process, linea alba, two third of inguinal ligament symphysis pubis transversus lower 6 costal cartilages, xiphoid process, linea alba, abdominis lumbar fascia, iliac crest, symphysis pubis lateral third of inguinal ligament rectus symphysis pubis, iliac crest 5th, 6th, 7th costal cartilages, xiphoid abdominis process pyramidalis anterior part of pubis linea alba External oblique muscle ( free posterior boarder ) * inguinal ligament * external inguinal ring ( superficial inguinal ring ) * external spermatic fascia Internal oblique muscle free boarder – arch over spermatic cord form conjoint tendon together with similar fibres of transversus abdominis muscle. Transversus abdominis muscle • free boarder – arch over spermatic cord • form conjoint tendon • together with similar fibres of internal oblique muscle • cremasteric muscle Neurovascular plane the plane between internal oblique and transverse abdominis muscle lower 5 intercostal nerves, subcostal nerve and first lumbar nerve and vessels run in neurovascular plane lateral and anterior cutaneous branches pierce through the muscle enter the rectus sheath by piercing its posterior wall rectus abdominis muscle long strap muscle extending from xiphoid process to symphysis pubis broader above linea alba separates the two rectus muscles muscle is enclosed in rectus sheath adherent to rectus sheath anteriorly, 3 constant tendinous intersections are formed at the tip of the xiphoid process at umbilicus and mid -way between 1 & 2 completely free behind ( not adherent to rectus sheath posteriorly) rectus sheath tendonous sheath ( in which rectus muscle lies ) formed by aponeurosis of lateral abdominal muscles fused in mid line ( linea alba ) posterior rectus sheath & its relations • xiphoid process and • costal cartilages • posterior layer of internal oblique aponeurosis • aponeurosis of transversus abdominis muscle • fascia transversalis • extra peritoneal pad of fat • parietal peritoneum no posterior rectus sheath free curved lower boarder of posterior wall of the rectus sheath “ arcuate line of Douglas ” where inferior epigastric vessels enter the rectus sheath to support the viscera to compress the abdomen to assist respiration ( expiration ) to move the trunk combination of muscles and aponeurosis in anterior abdominal wall give protection to the abdominal viscera muscles cross each other in such a way that it strengthen the abdominal wall Superior epigastric artery Inferior epigastric artery Deep circumflex iliac artery Superficial circumflex iliac artery Posteior intercostal artery Lumbar arteries Superior epigastric vein - internal thoracic Inferior epigatric vein & Deep circumflex vein - external iliac Posterior intercostal veins - azygos Lumbar veins - IVC anterior rami of lower 6 thoracic and first lumbar nerves passes forward in plane between internal oblique and transversus abdominis muscle ( neurovascular plane ) supply skin, muscles and parietal peritoneum first lumbar nerve supply skin over inguinal ligament & symphysis pubis Neurovascular plane segmental nerve supply referred pain * intercostal nerve blocks collection of pus superficial veins dilatation of superficial veins in anterior abdominal wall site ( abdomen / thorax ) direction of blood flow clinical conditions portal venous obstruction -dilated veins radiating out from the umbilicus vena cava obstruction “caput Medusae ” In portal venous obstruction, superficial veins of the abdominal wall around the umbilicus are dilated and tortuous as blood from the portal vein flow back through paraumbilical veins into superficial veins of the anterior abdominal wall. Vena caval obstruction SVC obstruction Vena caval obstruction IVC obstruction incisions aim at leaving abdominal wall as strong as possible after the operation, otherwise there exist a very real danger of bad weak scar and ventral hernia Principles Good access, direct access to the area of operation Allow extension if required No nerves must be divided Split the muscle in the direction of the fibres, rather than cut across Rectus abdominis muscle may be cut transversely without serious weakening Close the wound with no tension Incisions Mid line incisions Paramedian incisions Transverse incisions Kocher’s incision Incision through linea semilunaris * structures under your knife ? inguinal region Surface markings Iliac crest ASIS Symphysis pubis & pubic tubercle Note mid-inguinal point mid point of inguinal ligament mid inguinal point mid point of a line drawn between ASIS and symphysis pubis femoral artery lie deep to this point arterial puncture mid point of inguinal ligament mid point of a line drawn between ASIS and pubic tubercle deep inguinal ring lies 1.5 cm above this point ( important landmark to identify the deep inguinal ring ) inguinal ligament • formed by free edge of aponeurosis of external oblique muscle • extending from ASIS to pubic tubercle • edge is rolled inwards and form a gutter • provide origin for internal oblique & transversus abdominis muscles • fascia lata is attached to inguinal ligament mid point of inguinal ligament midinguinal point linea semilunaris IEA ASIS IR inguinal ligament F Lata pubic tubercle SyP parts of inguinal ligament Lacunar ligament triangular in shape, apex lies at the pubic tubercle, base is concave, free and laterally related to femoral canal Pectinate part oblique canal ( intermuscular slit ) in the inguinal region formed as a result of descent of testis through the abdominal wall 1.5 - 2 inches / 4 - 6 cm long lying downward and medially extending from internal to external inguinal ring above and parallel to medial half of inguinal ligament ASIS IEA IR inguinal ligament ER PT SyP External inguinal ring triangular opening in external oblique aponeurosis above and medial to the pubic tubercle as the cord traverses the opening, it carries “external spermatic fascia ” from the ring margin Internal inguinal ring opening in the transversalis fascia transversalis fascia forms “ internal spermatic fascia ” and is attached to the margins of internal ring the ring lies lateral to inferior epigastric vessels anterior relation skin, sup fascia, external oblique, internal oblique posterior relation IEV, fascia transversalis, conjoint tendon medially foor inguinal ligament roof arching fibres of internal oblique & transversus abdominis muscle spermatic cord ( round ligament of uterus ) ilio-inguinal nerve genital branch of genito-femoral nerve spermatic cord 3 layers of fascia external spermatic fascia ( from ext. oblique m ) cremasteric muscle ( from internal oblique m ) internal spermatic fascia ( from fascia transversalis ) 3 arteries testicular A – from abdominal aorta cremasteric A – from inferior epigastric artery artery to the vas – from inferior vesical artery 3 nerves nerve to cremaster – from genitofemoral N sympathetic fibres ilio-inguinal nerve 3 other structures vas deferens pampiniform plexus of veins lymphatics Clinical application Hernia , the most commonly seen problem in daily clinical practice Hydrocoele Torsion of the testis disposition of deep and superficial rings inguinal canal is oblique shutter mechanism of internal oblique and transversus abdominis muscles intra-abdominal pressure guy-rope action of inferior epigastric artery cremasteric muscle anterior abdominal wall hernias inguinal swelling / inguino-scrotal swelling Inguinal hernia hernia passing through the inguinal canal direct indirect Femoral hernia hernia passing through the femoral canal indirect direct in a preformed sac no preformed sac through internal ring, not through deep inguinal canal, external inguinal ring – but ring through Hesselbach’s neck of hernia is lateral triangle to IEV neck of hernia is medial to IEV inguinal hernia femoral hernia inguinal canal above and medial to femoral canal pubic tubercle below and lateral to into the scrotum pubic tubercle groin swelling growing downward then upwards clinical tests Revisit femoral triangle !!! Hydrocoele Accumulation of fluid in tunica albugenia No inguinal swelling. Varicocoele ! Torsion of the testis predisposing factors ???
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