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Abdominal Wall: Clinical Relevance Christopher Archer carcher08@qub.ac.uk • Abdominal incisions • Anterolateral Abdominal Wall • Musculature & Rectus Sheath • Posterior Abdominal Wall • Neurovasculature supply • Inguinal Canal Overview • Herniation • Caput Medusa • MCQsCommon Abdominal Incisions Layers of Anterolateral Abdominal Wall Musculature • External Oblique – lower 8 ribs to xiphoid process, linea alba, pubic crest, pubic tubercle & iliac crest.“Rolled-up” lower portion forms the inguinal ligament. • Internal Oblique – lumbar fascia, iliac crest & lateral 2/3 of inguinal ligament to lower 3ribs & costal cartilages, xiphoid process, linea alba & symphysis pubis. • TransversusAbdominus – lower 6 costal cartilages, lumbar fascia, iliac crest & lateral 1/3 of inguinal ligament to xiphoid process, linea alba & symphysis pubis. th • RethusAthominus – symphysis pubis & pubic crest to 5 , 6 & 7 costal cartilages & xiphoid process.Actions: • External & internal oblique muscles – compresses abdominal contents, assists in flexion & rotation of trunk, assistsin forced expiration, micturition, defecation etc. • Transversus abdominis – compresses abdominal contents. • Rectus abdominis – compresses abdominal contents,flexes vertebral column & accessory muscle of expiration. Rectus Sheath Formed by aponeuroses of the external & internal obliques& transversus abdominus, with anterior & posterior walls. Contents: - Rectus abdominis & pyramidalis muscles - Anterior rami of lower 6thoracic nerves - Superior & inferior epigastric vessels - Lymph vesselsThe walls of the sheath vary at 3 levels: Above the costal margin – anterior wall is the aponeurosis of external oblique only; posterior wall is 5-7 costal cartilages & intercostal spaces. Costalmargin to arcuate line – internal oblique splitsinto anterior & posterior laminae,enclosingthe rectus abdominis. Arcuateline to symphysispubis – aponeuroses of all 3muscles form anterior wall, no posterior wall – rectus abdominis is in contact with transversalis fascia.Posterior Abdominal Wall th • Iliopsoas - flexes • Quadratus lumborum – fixes12 rib during thigh on trunk. inspiration, depresses during forced expiration & laterally flexes vertebral column. Neurovascular Supply • Somatic innervation – sharp, intense,well localized • Anterior wall innervated by lower 6 thoracic nerves and first lumbar nerve – iliohypogastric & ilio- inguinal nerves • Posterior wall innervated by anterior rami of lumbar nerves L1- L3 (psoas major),anterior rami of subcostal & L1-L4 nerves (Q.L) & the femoral nerve (iliacus) • Arterial Supply: Above the Umbilicus Branches of Thoracic aorta– posterior intercostal arteries 10-11& subcostal artery Branches of Abdominal Aorta – lumbar arteries 1-4 & inferior phrenic arteries Branches of Internal Thoracic Artery – superior epigastric & musculophrenic arteries Branches of External Iliac Artery - inferior epigastric and deep circumflexiliac arteries • Below theUmbilicus: Branches of Femoral Artery - superficial epigastric, superficial circumflex iliac, & superficial external pudendal arteriesVenous Drainage • Network of veins radiating from umbilicus • Drained above into axillary vein via lateral thoracic vein • Drained below into femoral vein via the superficial epigastric & the great saphenous veins • Paraumbilical veins form a portal- systemic venous anastomosis Inguinal Canal Oblique passage through the anterolateral abdominal wall; parallel and superior to the inguinal ligament. Approx. 4cm long from the deep inguinal ring, an opening in the transversalis fascia just above the midpoint of the inguinal ligament, to the superficial inguinal ring,an openingin external oblique aponeurosis just superior to the pubic tubercle. Boundaries: • Anterior – aponeurosis of external oblique,reinforced by internal oblique laterally • Posterior – transversalis fascia • Roof – transversalis fascia, internal oblique & transversus abdominis • Floor – inguinal ligamentContents: • Spermatic cord in males • Round ligament in females • Ilioinguinal nerve • Genital branch of genitofemoral nerve• Hesselbach’s/Inguinal Triangle: Herniation: Protrusion of abdominal weakness/defectiveness inf the abdominal wall. • Painless lump which may protrude duringcoughing, straining, or any activity which increases intra-abdominal Hernia Presentations: pressure • Patient may describe being able to “push it back in” i.e., reduce it • Investigations = USS/CT scan • Irreducible hernias represent a greater risk for strangulation – restriction of arterial supply • Strangulation considered a medical emergency; patient often presents with sudden,severe pain, & symptoms of bowel obstruction such as nausea,vomiting,constipation etc. • Requires immediate surgery to relieve the herniaInguinal Hernias – 75% of Abdominal Hernias • Passes through the inguinal canal i.e., the deep and superficial inguinal rings • Follows the path of the testes during descent through theprocessus vaginalis • Mass is in the spermatic cord & often found in the scrotum/labia • Mass is lateral to inferior epigastric artery • More prevalent in males (x20)• Passes through area of weakness in posterior wall of the inguinal canal • Mass is adjacent to spermatic cord & rarely protrudes into the scrotum/labia • Mass is medial to inferior epigastric arteryCaput Medusae: • Distension of the superficial veins around the umbilicus & the para-umbilical veins which anastomose with the portal vein due to portal hypertension • Most commonly caused by liver cirrhosis • Other causes include portal vein thrombosis, schistosomiasis & Budd Chiari syndromeMCQs: A patient presents with a • Direct inguinal painless protruding mass in his right inguinal region. • Para-umbilical When you apply pressure to it, the mass reduces however when the deep • Indirect inguinal inguinal ring is covered and the patient told to cough, the mass reappears. What is • Femoral the best description of this hernia? • Incisional • Fascia of external oblique If a surgeon is performing a left • Rectus abdominis paramedian incision below the arcuate line, what is the last • External oblique muscle layer which he will cut through before reaching the • Fascia of internal oblique muscle transversalis fascia? • Transversus abdominis muscle • Subcostal artery, lumbar arteries 1-4, inferior phrenic artery & external iliac artery • Superficial epigastric, superficial external A surgeon is pudendal & deep circumflex iliac arteries performing a laparoscopic repair • Abdominal aorta, external iliac artery & of an inguinal hernia femoral artery and asks you what the arterial supply of • Superficial epigastric, superficial circumflex this region is. iliac, & superficial external pudendal arteries • Superficial epigastric, superficial external iliac, & superficial internal pudendal arteries • Lanz incision, transversely crosses point2/3 way to umbilicus from rightASIS You are asked to perform an abdominal examination on a 50-year-old woman who • Rutherford-Morrison incision, runs obliquely inferiorly from 2cm above ASIS presents with jaundice, RUQ pain and fever. On your inspection, you notice a scar • Transverse incision across McBurney’s point in the right lower quadrant, the patient informs you this was from an appendectomy • McBurney incision, runs obliquely through McBurney’s pointin leftlower quadrant when she was a child. Whatis the name and location of the incision? • Lanz incision, transversely crosses point 2/3 way from umbilicus to right ASISQuestions?