Anatomy of the Abdomen I PDF

ANATOMY OF THE ABDOMEN DANNY STREIN THE ABDOMEN • Body space between the thorax and the pelvis bounded by the diaphragm superiorly and the inguinal ligament and pelvic bones inferiorly • The largest cavity in the human body • Organs include: • • • • • • • • • Stomach Small Intestine Large Intesti...

ANATOMY OF THE ABDOMEN DANNY STREIN THE ABDOMEN • Body space between the thorax and the pelvis bounded by the diaphragm superiorly and the inguinal ligament and pelvic bones inferiorly • The largest cavity in the human body • Organs include: • • • • • • • • • Stomach Small Intestine Large Intestine Liver Gallbladder Spleen Pancreas Kidneys Adrenal Glands DEFINITIONS • Aponeurosis – flat broad tendon-like layers that serve as attachments for muscles • Fascia – A thin sheath of fibrous tissue enclosing a muscle or other organ • Peritoneum – serous membrane that lines the abdominal cavity and its organs • Parietal and visceral • (Peritoneal) Ligament – a double layer of peritoneum that connects one organ to another organ or to the abdominal wall • Mesentery – a fold of the peritoneum that attaches the stomach, small intestine, pancreas, spleen, and other organs to the posterior wall of the abdomen • Omentum – a double-layered fatty sheath that supports and protects abdominal organs SUBDIVISIONS When we describe the Abdomen we break it down into 4 quadrants or 9 regions: • 4 Quadrants are defined by two planes: • Median Plane • Transumbilical Plane Median Plane • 4 Quadrants: RUQ LUQ RLQ LLQ • 9 Regions: • Right and Left hypochondriac – under the ribs • Right and Left lumbar – flanks • Right and Left inguinal – groin • Epigastric – over the stomach • Umbilical • Pubic/Hypogastric – under the stomach Transumbilical Plane SUBDIVISIONS Median Plane Transumbilical Plane SUBDIVISIONS Right Hypochondriac: Epigastric: Left Hypochondriac: Liver Gallbladder Small Intestine Ascending/Transverse Colon Right Kidney Right Adrenal Gland Right Ureter Esophagus Stomach Liver Pancreas Small Intestine Transverse Colon R/L Kidneys R/L Adrenal Glands R/L Ureters Stomach Liver (tip) Pancreas (tail) Small Intestine Transverse/Descending Colon Spleen Left Kidney Left Adrenal Gland Left Ureter Right Lumbar: Umbilical: Left Lumbar: Liver Gallbladder Small Intestine Ascending Colon Right Kidney/Ureter Stomach Pancreas Small Intestine Transverse Colon R/L Kidneys/Ureters Small Intestine Descending Colon Left Kidney/Ureter Right Iliac: Hypogastric: Left Iliac: Small Intestine Appendix Cecum/Ascending Colon Right Ovary/Fallopian Tube Small Intestine Sigmoid Colon/Rectum R/L Ovaries/Fallopian Tubes Urinary Bladder Uterus Vas Deferens/Seminal Vesicles Spermatic Cord Prostate Small Intestine Descending/Sigmoid Colon Left Ovary/Fallopian Tube SURFACE ANATOMY Xiphoid process Linea Alba Costal Margin Linea Semilunaris* Umbilicus ASIS/Iliac Crest Inguinal Groove http://thevoicenotes.com/wp-content/uploads/2013/07/Fig._9.1_B.jpg *Spigelian Hernias  spontaneous lateral ventral hernias XIPHOID PROCESS • Thin cartilaginous extension off of the sternum • Easily palpated in the depression where the costal margins meet in the upper part of the anterior abdominal wall Xiphisternal Junction – where the xiphoid joins the sternum • Lies opposite the 9th thoracic vertebra Epigastric Fossa • A small depression located in the upper-most midline abdomen in the infraxiphoid area http://www.hxbenefit.com/wpcontent/uploads/2013/07/XiphoidProcess-Picture.jpg COSTAL MARGIN • The curved lower margin of the thoracic wall formed anteriorly by the cartilage of the 7th, 8th, 9th and 10th ribs and posteriorly by the cartilage of the 11th and 12th ribs Why is this important? LINEA ALBA • Fibrous band that extends from the symphysis pubis (inferiorly) to the xiphoid process (superiorly) and lies in the midline • Fusion of the aponeuroses of the muscles of the anterior abdominal wall and is represented on the surface by a slight median groove – “rhaphe” = suture/seam • -rrhaphy  tenorrhaphy LINEA ALBA http://cdn-maf0.heartyhosting.com/sites/muscleandfitness.com/files/media/abs8-pack_2.jpg https://happitraining.files.wordpress.com/2013/04/linea-alba.jpg UMBILICUS • Lies in the linea alba and is inconstant in position • Puckered scar at the site of attachment of the umbilical cord in the fetus • Located at L4 • Aorta bifurcates at vertebral level L4 LINEA SEMILUNARIS • Lateral edge of the rectus abdominis muscles • Crosses costal margin at the tip of the 9th costal cartilage ILIAC CREST • May be felt along its entire length and ends anteriorly at the Anterior Superior Iliac Spine (ASIS) • ASIS = highest point  lies opposite L5 http://www.jouefct.com/wp-content/uploads/2015/12/howto-check-your-pelvis-asis-anatomy-posterior-superior-iliacspine-pain-anterior-iliac-crest-pain.png DIAPHRAGM • Dome-shaped, musculotendinous partition separating the thoracic and abdominal cavities • Made up of central tendon with muscular attachments to the xiphoid process, inferior thoracic cage and superior lumbar vertebrae • Right dome is typically higher than left http://antranik.org/muscles-of-the-thorax-for-breathing-and-the-pelvic-floor-the-diaphragm/ DIAPHRAGMATIC APERTURES • Caval Opening • Aperture in the central tendon for IVC • IVC is adherent to opening  as diaphragm contracts during inhalation, IVC dilates facilitating blood flow to the heart • Right phrenic nerve, some lymphatics also pass through • Esophageal Hiatus • Oval aperture through which the esophagus passes • Anterior/posterior vagal trunks, esophageal branches of the left gastric vessels, lymphatics • Hiatal hernia* • Aortic Hiatus • Opening posterior to the diaphragm • DOES NOT PIERCE diaphragm  not affected by movements during respiration • Aorta, azygos vein, thoracic duct http://www.clevelandclinic.org/healthinfo/ShowImage. ashx?PIC=4036 VASCULATURE OF THE DIAPHRAGM Arterial Supply: • Superior Surface – superior phrenic arteries from thoracic aorta; musculophrenic and pericardiacophrenic from the internal thoracic arteries • Inferior Surface – inferior phrenic arteries from abdominal aorta Phrenic = Diaphragm Venous Drainage: • Superior Surface – Musculophrenic and pericardiacophrenic veins drain into internal thoracic vein; superior phrenic vein (right side) drains into IVC • Inferior Surface – Inferior phrenic veins; right vein drains into IVC; left vein is doubled and drains into IVC and left suprarenal vein INNERVATION OF THE DIAPHRAGM Motor Supply: • Phrenic nerves (C3-C5) Sensory Supply: • Centrally by phrenic nerves (C3-C5) • Peripherally by intercostal nerves (T5-T11) and subcostal nerves (T12) *C3, 4, 5 keep the diaphragm alive!* ANTEROLATERAL ABDOMINAL WALL Made up of: Skin (epidermis/dermis) Subcutaneous tissue Fascias • Camper’s fascia – fatty superficial layer • Continuous with the superficial fat of the rest of the body • May be extremely thick in obese patients • Scarpa’s fascia – deep membranous layer • Fades out over the thoracic wall above and along the midaxillary line laterally; inferiorly it passes onto the front of the thigh where it fuses with the deep fascia • Extends over the penis where it helps form Dartos fascia • Colle’s fascia – extension of Scarpa’s into the perineum • Investing fascia (epimysium) – lines muscle Muscles Endoabdominal fascia – lines organs  named for organ it lines (transversalis) Parietal peritoneum* – lines abdominal cavity MUSCLES OF THE ABDOMINAL WALL • Abdominal Wall consists of 5 muscles • 3 flat muscles, 2 vertical • All three flat muscles end anteriorly in a strong, sheet-like aponeurosis • Fibers of each aponeurosis interweave at the linea alba with the corresponding muscle of the opposite side forming the rectus sheath MUSCLES OF THE ABDOMINAL WALL 3 Flat Muscles: • External Oblique • Most superficial • Largest • Runs inferomedially (“down and in”) • Internal Oblique • Intermediate • Runs superomedially (“up and in”) • Transversus Abdominis • Deepest • Runs horizontally and in – fans out *All 3 muscles terminate in an anterior aponeurosis forming the rectus sheath* MUSCLES OF THE ABDOMINAL WALL External Oblique • Origin: Lower 8 ribs • Insertion: Xiphoid process, linea alba, pubic crest, pubic tubercle, iliac crest • Nerve Supply: Lower 6 thoracic nerves • Action: Supports abdominal contents; assists in forced expiration, micturition, defecation, parturition, vomiting; flexion and rotation of trunk The lower border of the aponeurosis is folded back on itself forming the inguinal ligament INGUINAL LIGAMENT https://vignette2.wikia.nocookie.net/ranzcrpart1/images/c/cc/Card-11072237-back.jpg/revision/latest?cb=20150503015259 MUSCLES OF THE ABDOMINAL WALL Internal Oblique • Origin: Lumbar fascia, iliac crest, lateral 2/3rds of the inguinal ligament • Insertion: Lower three ribs and costal cartilages, xiphoid process, linea alba, symphysis pubis • Nerve Supply: Lower 6 thoracic nerves • Action: Same as External Oblique MUSCLES OF THE ABDOMINAL WALL https://yeditepeanatomylab.files.wordpress.com/2014/04/cadaver-2-anterolateral-abdominal-wall.jpg MUSCLES OF THE ABDOMINAL WALL MUSCLES OF THE ABDOMINAL WALL Transversus Abdominis • Origin: Lower 6 costal cartilages, lumbar fascia, iliac crest, lateral 3rd of the inguinal ligament • Insertion: Xiphoid process, linea alba, symphysis pubis • Nerve Supply: Lower 6 thoracic nerves • Action: Compresses abdominal contents http://newbridgespine.com/wpcontent/uploads/2015/07/transversus_abdominis-637x631.jpg MUSCLES OF THE ABDOMINAL WALL 2 Vertical Muscles • Rectus Abdominis • Long, broad, strap-like • Mostly enclosed in the rectus sheath • Muscle fibers run between 3 or more tendinous intersections  “six pack” • Pyramidalis • Small, triangular • Lies in the rectus sheath anterior to the inferior rectus abdominis • Ends in linea alba and tenses it • Absent in 20% of population MUSCLES OF THE ABDOMINAL WALL Rectus Abdominis • Origin: Symphysis pubis and pubic crest • Insertion: 5th, 6th, and 7th costal cartilages and xiphoid process • Nerve Supply: Lower 6 thoracic nerves • Action: Compresses abdominal contents; flexes vertebral column http://cloud2.golfloopy.com/wpcontent/uploads/2012/04/Rectus-Abdominis-Muscle.jpg It is enclosed between the aponeuroses of the external oblique, internal oblique and transversus abdominis, which forms the rectus sheath MUSCLES OF THE ABDOMINAL WALL Pyramidalis • Origin: Anterior surface of pubis • Insertion: Linea alba • Nerve Supply: 12th thoracic nerve • Action: Tenses the linea alba (May be absent) MUSCLES OF THE ABDOMINAL WALL Rectus Sheath • Formed by the interweaving aponeuroses of the flat muscles • Contains: • Rectus abdominis • Pyramidalis • Superior/Inferior epigastric arteries (run along linea alba) • Lymphatic vessels – lower abdomen  drainto horizontal inguinal nodes • Portions of spinal nerves T7-T12 MUSCLES OF THE ABDOMINAL WALL Rectus Sheath • Arcuate line AKA linea semicircularis – horizontal line demarcating the lower limits of the posterior layer of the rectus sheath • Arcuate line occurs halfway between umbilicus and pubis http://www.instantanatomy.net/abdomen/areas/abdominalwallanterio r/rectussheath.html http://web.duke.edu/anatomy/Lab05/images/lab5-step2k.jpg https://www.pinterest.com/pin/801148221195570920/?lp=true THE ABDOMINAL WALL Functions: • Strong, yet flexible support • Contain viscera and protect from injury • Oppose or assist diaphragm in maintaining or increasing intraabdominal pressure • Helps to eliminate gas • Expiration, sneezing, coughing • Helps to eliminate liquid, solid • Urination, defecation, vomiting • Move the trunk and help maintain posture THE ABDOMINAL WALL Sherren’s Triangle: • A triangle formed by an imaginary line from the anterior superior iliac spine (ASIS), to the umbilicus, down to the pubic symphysis and back to the ASIS Hyperaesthesia of the skin in this triangle may indicate acute appendicitis INNERVATION OF THE ABDOMINAL WALL Dermatomes • C4 = Clavicle • C7 = &%#! • T4 = Nipple • T10 = Umbilicus • L1 = Groin • L5 = Top of feet DERMATOMES https://med.libretexts.org/Bookshelves/Anatomy_and_Physiology/B ook%3A_Anatomy_and_Physiology_(Boundless)/12%3A_Peripheral_ Nervous_System/12.6%3A_Spinal_Nerves/12.6E%3A_Dermatomes INNERVATION OF THE ABDOMINAL WALL Innervation: • T7-T12/L1 supply the muscles and skin of the abdominal wall • Thoracoabdominal (T7 – T11) – muscles of anterolateral abdominal wall and overlying skin • Subcostal nerves (T12) – muscles of anterolateral abdominal wall and overlying skin superior to iliac crest and inferior umbilicus • Iliohypogastric (L1) – skin overlying iliac crest, upper inguinal and hypogastric regions; internal oblique and transversus abdominis • *Inferior branch ilioinguinal nerves (L1) – skin of scrotum or labium majus, mons pubis, and adjacent medial aspect of thigh; most inferior internal oblique and transversus abdominis *Think hernia repair VASCULATURE OF THE ABDOMINAL WALL Arteries: • Musculophrenic – internal thoracic artery; abdominal wall of hypochondriac region, anterolateral wall, diaphragm • Superior Epigastric – terminal branch of the internal thoracic artery; supplies the rectus abdominis and upper central part of the anterior abdominal wall • Inferior Epigastric – branch of the external iliac artery just above the inguinal ligament; supplies the lower central part of the anterior abdominal wall • Superficial Epigastric – branches off femoral artery; supplies subcutaneous tissue and skin over pubic and inferior umbilical region • Superficial Circumflex Iliac – branches off femoral artery; supplies superficial abdominal wall of inguinal region and adjacent anterior thigh • Deep Circumflex Iliac – branch of the external iliac artery; supplies lower lateral part of the abdominal wall • Posterior Intercostal Arteries (10th/11th)/Subcostal – branches of the descending thoracic aorta; supply the lateral part of the abdominal wall VASCULATURE OF THE ABDOMINAL WALL VASCULATURE OF THE ABDOMINAL WALL https://image.slidesharecdn.com/anatomyofaaw-121028075853-phpapp02/95/anatomy-of-aaw-62-638.jpg?cb=1351411549 ANATOMY OF THE GROIN Inguinal Ligament: • Formed by the external abdominal oblique aponeurosis and is continuous with the fascia lata of the thigh • Rolled under inferior margin of the external oblique muscle • Runs from the ASIS curving downward to the pubic tubercle of the pubic bone Symphysis Pubis: • Cartilaginous joint that lies in the midline between the bodies of the pubic bones • Felt as a solid structure beneath the skin in the midline of the anterior abdominal wall • Pubic Crest: ridge of the superior surface of the pubic bones medial to the pubic tubercle http://clinicalgate.com/wpcontent/uploads/2015/06/B9781455710782000055_f00 5-011-9781455710782.jpg ANATOMY OF THE GROIN Inguinal Canal: • Inguinal canal lies parallel to inguinal ligament • Tubular structure that runs inferomedially and contains the spermatic cord in males and the round ligament in females • Formed during development as the gonads relocate Superficial (External) Inguinal Ring: • Triangular aperture in the aponeurosis of the external oblique muscle situated above and medial to the pubic tubercle • In males – the margins can be felt by invaginating the skin of the upper part of the scrotum with the tip of the finger • In females – smaller and difficult to palpate Deep (Internal) Inguinal ring: • Internal opening canal • 1 cm above midpoint of inguinal ligament ANATOMY OF THE GROIN https://teachmeanatomy.info/abdomen/areas/inguinal-canal/ ANATOMY OF THE GROIN Hasselbach’s Triangle: • Triangular area of the inferior aspect of the anterior abdominal wall within the groin Boundaries: • Inferior: inguinal ligament • Superior: inferior epigastric vessels • Medial: rectus sheath • The site of DIRECT inguinal hernias HERNIAS Direct Inguinal Hernias: • Usually men over 40 • Rare in women http://clinicalgate.com/wpcontent/uploads/2015/04/B9781455706068000446_f044-0039781455706068.jpg • 55% bilateral • Above the inguinal ligament • Directly behind and through the external inguinal ring • Rarely enters the scrotum • Hernia pushes the side of the examiner’s finger in inguinal canal HERNIAS Indirect Inguinal Hernias: • • • • • Most common type All ages 30% bilateral Swelling ABOVE inguinal ligament Abdominal contents through the internal inguinal ring often into the scrotum • Hernia comes down the inguinal canal and touches the examiner’s fingertip • Failure of obliteration of processes vaginalis  deep inguinal ring doesn’t close http://clinicalgate.com/wp-content/uploads/2015/04/B978145570606 8000446_f044-002-9781455706068.jpg HERNIAS https://i.pinimg.com/736x/56/ed/d1/56edd195212e09b18c80497923f142a6--hernia-inguinal-visual-aids.jpg HERNIAS Femoral Hernias: • • • • • Least common of all the groin hernias More common in women Passes below the inguinal ligament Never enters scrotum Inguinal canal is empty http://www.medicalrealm.net/uploads/1/2/7/3/12737542/1402532281.jpg HERNIAS http://www.clinicalexams.co.uk/wpcontent/uploads/2016/02/Inguinal-hernia-exam-BE-600x600.jpg HERNIAS Spigelian Hernias: • A hernia through the Spigelian fascia, which is the aponeurotic layer between the rectus abdominis muscle medially, and the semilunar line laterally. http://blog.gtsmeditour.com/spigelian-hernias-causes-symptoms-treatments/ HERNIAS Spigelian Hernias: https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-018-0449-5 https://www.thesurgeonscollective.com.au/conditions/types-of-herniahiatal-incisional-ventral-femoral-hernia-perth SURGICAL INCISIONS • Median/Midline • Paramedian • Gridiron • Pfannenstiel • Transverse • Subcostal PERITONEUM • The abdominal cavity is lined with a protective membrane termed the peritoneum • The abdominal wall is covered by the parietal peritoneum • The viscera are covered by the visceral peritoneum • The kidneys are located in the abdominal cavity behind the peritoneum, in the retroperitoneum PERITONEUM • Two continuous layers of serous membrane • Parietal – lines surface of the abdominopelvic wall • Visceral – invests organs • Intraperitoneal organs almost completely covered with visceral peritoneum • Every organ must have an area that is not covered with visceral peritoneum to allow entrance/exit of neurovascular structures  bare area • Extraperitoneal, retroperitoneal, and subperitoneal are only partially covered PERITONEUM Retroperitoneal http://www.macmillan.org.uk/_images/MACD049_Side-view-of-female-organs_labelled_20151215_large_tcm9-244765.jpg PERITONEUM • Between the visceral and parietal peritoneum is the peritoneal cavity, which is a potential space • No viscera in the peritoneal cavity • Peritoneal fluid lubricates surfaces of viscera, allowing for movements of digestion • Also contains leukocytes and antibodies that resist infection • The peritoneum divides the cavity into numerous compartments PERITONEUM Peritoneal Cavity: • Completely closed in males • In females there is a communicating pathway with the exterior world through the uterine (fallopian) tubes, uterine cavity and vagina that is a potential pathway for infection • ie: PID PERITONEUM • Peritonitis – inflammation of peritoneum • Person with acute abdomen has guarding – board like muscular rigidity that cannot be willfully suppressed • Peritoneal adhesions – if peritoneum is damaged by a stab wound or from abdominal surgery, part of the parietal and visceral peritoneum can become inflamed and may adhere to each other during healing  can interfere with movement of the viscera/digestion PERITONEUM Descriptive Terms: • Mesentery • Peritoneal Ligament • Omentum MESENTERY • Double layer of peritoneum reflecting away from abdominal wall to enclose part or all of one of the viscera • Example: transverse mesocolon • Provides means for neurovascular communication between the organ and body wall • Viscera with mesentery are mobile • Degree of mobility depends on length of mesentery MESENTERY http://www.apsubiology.org/anatomy/2020/2020_Exam_Reviews/Exam_3/mesenteries.jpg PERITONEAL LIGAMENT • Double layer of peritoneum that connects an organ with another organ or to the abdominal wall • Liver is connected to anterior abdominal wall by falciform ligament • Broad ligament of the uterus  peritoneal fold that attaches the uterus, fallopian tubes, and ovaries to the pelvis http://www.studydroid.com/imageCards/0q/hv/card-27852205-front.jpg OMENTUM • A large apron-like fold of visceral peritoneum that hangs down from the greater curvature of the stomach • Passes in front of the small intestines and reflects on itself to ascend to transverse colon • First structure observed when the abdominal cavity is opened anteriorly Functions of the Greater Omentum: • Fat deposition • Immune contribution • Macrophage collections • Infection and wound isolation • “policeman of the abdomen” – walls off infection GREATER OMENTUM • Broad, double layered sheet of peritoneum passing from stomach to another abdominal organ Greater Omentum • Connects greater curvature of stomach to another viscus • 3 Parts: • Gastrocolic ligament – stomach to transverse colon • Descends anteriorly past the transverse colon then returns to colon • Descending and ascending portions usually fuse together forming a four-layered fatty “omental apron” • Gastrosplenic ligament – stomach to spleen • Gastrophrenic ligament – stomach to diaphragm GREATER AND LESSER OMENTUMS http://images.slideplayer.us/1/273759/slides/slide_10.jpg LESSER OMENTUM Lesser Omentum • Located behind the stomach • Connects lesser curvature of stomach to another viscus • 2 Parts: • Hepatogastric ligament – stomach to liver • Hepatoduodenal ligament - connects the lesser curvature of the stomach and the proximal part of the duodenum to the liver • Conducts the portal triad* SUBDIVISIONS OF THE PERITONEAL CAVITY The peritoneal cavity is divided into a greater sac and an omental bursa: Greater Sac • Main/larger part of the peritoneal cavity Omental Bursa – AKA “lesser sac” • Smaller part of peritoneal cavity • Posterior to stomach • Permits free movement of the stomach on adjacent structures • 2 Recesses: • Superior and Inferior • Greater and Lesser Sac communicate through the Omental Foramen (AKA Epiploic Foramen/Foramen of Winslow)* SUBDIVISIONS OF THE PERITONEAL CAVITY * Superior Recess Inferior Recess http://teachmeanatomy.info/wp-content/uploads/Greater-and-Lesser-Sacs-Greater-and-LesserOmenta-and-the-Stomach.jpg POSTERIOR ABDOMINAL WALL From deep to superficial: • 5 Lumbar vertebrae • Posterior abdominal wall muscles • Psoas, quadratus lumborum, iliacus, transversus abdominis, obliques • Lumbar Plexus • Fascias • Diaphragm • Fat, nerves, vessels, and lymph nodes POSTERIOR ABDOMINAL WALL Retroperitoneum: • The retroperitoneal space (retroperitoneum) is the anatomical space behind (“retro”) the peritoneum • Has no delineating anatomic structures • Organs are retroperitoneal if they have peritoneum on their anterior side only • Structures that are not suspended by mesentery in the abdominal cavity and that lie between the parietal peritoneum and abdominal wall are classified as retroperitoneal POSTERIOR ABDOMINAL WALL Retroperitoneal Structures A BAD PUCKER: • A = Aorta • B = Bladder • A = Adrenal glands • D = Duodenum • P = Pancreas • U = Ureters/Uterus* • C = Colon • K = Kidneys • E = Esophagus • R = Rectum * Ovaries http://droualb.faculty.mjc.edu/Lecture%20Notes/Unit%206/Spring%2006%20Digestive%20system%20with%20figures.htm POSTERIOR ABDOMINAL WALL Retroperitoneal Structures https://i.pinimg.com/736x/02/41/1b/02411bed5817c774ab34b93457696c8f --retroperitoneal-space-body-painting.jpg http://accessmedicine.mhmedical.com/data/books/980/bru_ch35_f016.png POSTERIOR ABDOMINAL WALL Retroperitoneal Structures http://ueu.co/wp-content/uploads/2014/09/loadBinaryCAKFJUUG.jpg POSTERIOR ABDOMINAL WALL Retroperitoneal Muscles: • Psoas Major: • Long fusiform muscle located to the side of the lumbar vertebral column and brim of the lesser pelvis • Joins the iliacus muscle to form the iliopsoas MUSCLES OF THE POSTERIOR ABDOMINAL WALL https://clinicalgate.com/wpcontent/uploads/2015/03/B9780443066849500706_gr4.jpg http://accessmedicine.mhmedical.com/data/books/mort/mort_c011f001.gif MUSCLES OF THE POSTERIOR ABDOMINAL WALL Retroperitoneal Muscles: • Psoas Major: • Long fusiform muscle located to the side of the lumbar vertebral column and brim of the lesser pelvis • • • • • Joins the iliacus muscle to form the iliopsoas Superior Attachments: Transverse processes of lumbar vertebrae; sides of bodies of T12-S1 vertebra and intervening IV discs Inferior Attachments: Lesser trochanter of the femur Nerve Supply: Lumbar plexus via anterior branches of nerves L2-L4 Action: Acting inferiorly with iliacus, flexes thigh; acting superiorly, flexes vertebral column laterally to balance the tunk; when sitting, acts inferiorly with iliacus to flex the trunk MUSCLES OF THE POSTERIOR ABDOMINAL WALL http://img.tfd.com/MosbyMD/thumb/psoas-major-and-minor.jpg MUSCLES OF THE POSTERIOR ABDOMINAL WALL Retroperitoneal Muscles: • Psoas Minor: • Long, slender skeletal muscle located anterior to psoas major • Iliacus: • Usually described in conjunction with the Psoas muscle as the iliopsoas muscle • Superior Attachments: Superior 2/3rds of the iliac fossa, ala of sacrum and anterior sacro-iliac ligaments • Inferior Attachments: Lesser trochanter of the femur and shaft inferior to it, and psoas major tendon • Nerve Supply: Femoral nerve (L2-L4) • Action: Flexes thigh and stabilizes hip joint MUSCLES OF THE POSTERIOR ABDOMINAL WALL Retroperitoneal Muscles: • Quadratus Lumborum: • Muscle of the lower back • • • • • Inserts into the lower border of the 12th rib and by four small tendons into the transverse processes of the upper four lumbar vertebrae Superior Attachments: Medial half of inferior border of 12th rib and tips of lumbar transverse processes Inferior Attachments: Iliolumbar ligament and internal lip of iliac crest Nerve Supply: Anterior branches of T12 and L1-L4 nerves Action: Extends and laterally flexes vertebral column; fixes 12th rib during inspiration* MUSCLES OF THE POSTERIOR ABDOMINAL WALL https://www.epainassist.com/images/quadratus-lumborum-strain.jpg MUSCLES OF THE POSTERIOR ABDOMINAL WALL • The iliopsoas has extensive and clinically important relations to the kidneys, ureters, cecum, appendix, sigmoid colon, pancreas, lumbar lymph nodes, and nerves of the posterior abdominal wall • When any of these structures is diseased, movement causes pain • Raise Leg against resistance • +Psoas sign  acute appendicitis FASCIA OF THE POSTERIOR ABDOMINAL WALL • Posterior abdominal wall is covered with a continuous layer of endoabdominal fascia that lies between the parietal peritoneum and the muscles • Continuous with transversalis fascia that lines transverse abdominal muscle • Structure is named according to the structure it covers • ex: psoas fascia INNERVATION OF THE POSTERIOR ABDOMINAL WALL Somatic: • Subcostal nerves (T12) – supply external oblique and skin • Lumbar nerves – supply deep back muscles and skin of back • Lumbar plexus (L1-L4) – and its branches: • Obturator (L2-L4) – supplies adductor muscles • Femoral (L2-L4) – supplies iliacus, flexors of hip, extensors of knee • Lumbosacral trunk (L4, L5) • *Ilioinguinal and iliohypogastric (L1) – supply abdominal muscles and skin of the pubic and inguinal regions • Must be accounted for in hernia repair* • *Genitofemoral (pubococcygeal) (L1, L2) – within spermatic cord • Lateral cutaneous (L2, L3) – supplies skin of anterolateral thigh INNERVATION OF THE POSTERIOR ABDOMINAL WALL http://accessanesthesiology.mhmedical.com/data/books/atch1/atch1 _c151f004.png http://accessmedicine.mhmedical.com/data/books/mort/mort_c011f 003.gif INNERVATION OF THE POSTERIOR ABDOMINAL WALL Autonomic: • Consists of one cranial nerve (vagus) and several different splanchnic nerve plexuses INNERVATION OF THE POSTERIOR ABDOMINAL WALL Autonomic: Vagus Nerve: • Cranial Nerve X – interfaces with the autonomic parasympathetic control of the heart and digestive tract • Right and Left vagus nerves descend from the cranial vault and travel between the internal and external carotids • Pass down the neck to the chest and into the abdomen • Contributes to the innervation of the viscera to the splenic flexure of the colon • Vagus nerve conveys sensory information about the state of the body’s organs to the CNS INNERVATION OF THE POSTERIOR ABDOMINAL WALL VASCULATURE OF THE POSTERIOR ABDOMINAL WALL Aterial Supply: Abdominal Aorta: • Most of the arteries supplying the posterior wall arise from the abdominal aorta • Four or five pairs of lumbar arteries rise from abdominal aorta and supply lumbar vertebrae, back muscles and posterior abdominal wall VASCULATURE OF THE POSTERIOR ABDOMINAL WALL http://accessmedicine.mhmedical.com/data/books/mort/mort_c011f002.gif VASCULATURE OF THE POSTERIOR ABDOMINAL WALL Venous Return: Inferior Vena Cava: • Veins of the posterior abdominal wall are tributaries of the IVC except for the LEFT testicular or ovarian vein (gonadal vein), which enter the LEFT renal vein instead of the IVC SPECIAL THANKS TO ALL THOSE THAT CAME BEFORE ME: • Mary Flanagan • Edgar Borero • Phil Lowenstein with help from Mike Lace