Intro to the Abdomen: Regions of the Abdomen Abdominal Wall Layers Abdominal Circulation Abdominal Nerve Supply Abdominopelvic Embryology The Abdomen - Located between the thorax and pelvis - Abdominal cavity o Separated from the thoracic cavity by thoracic diaphragm o Continuous inferiorly with pelvic cavity o Receives some protection by thoracic cage and greater pelvis o Location of most digestive organs, the spleen, kidneys and most of the ureters o Surrounded by multi-layered abdominal wall Abdominal Surface anatomy - Abdomen divided into regions for digestive purposes - Providing specific organ locations - May assist in identifying sources of pain - Quadrants vs. regions - Quadrants: o Formed by two planes o Horizontal plane: transumbilical plane . runs through the umbilicus at L3/4 IVD o Vertical plane: median plane - 9 regions o Subcostal plane . Passes through inferior borders of the 10th costal cartilages o Transtubercular plane . Passes through iliac tubercles – L5 post ASIS o Midclavicular plane . Pass from mid-point of clavicles to midinguinal points Abdominal Wall - Anterolateral wall made up of o Skin o Subcutaneous tissue – superficial fascia and fat o Mm o Deep fascia o Extraperitoneal fat o Parietal peritoneum o The mm: . Flat MM External oblique (superficial) o O: ext. surface of ribs 5-12, ant. ½ iliac crest o I: linea alda, pubic tubercle o N: thoracoabdominal nn (ventral rami inf. 6 thoracic nn) o MA: flexion and rotation of trunk, compression and support abdominal viscera o Fibres run inferiomedially Internal oblique (intermediate) o O: Thoracolumbar fascia, ant. 2/3rd iliac crest, lat. ½ inguinal lig. o I: Inf. Borders 10-12th ribs, linea alba, pectineal line via the conjoint tendon o NS: Thoracoabdominal and first lumbar nn o MA: F&R trunk and C&S Transverse abdominal (innermost) o O: Thoracolumbar fascia, ant. 2/3rd iliac crest, lat. ½ inguinal lig. o I: Inf. Borders ribs 10-12, linear alba, pectineal line via conjoint tendon o NS: Thoracoabdominal nn and first lumber nn o MA: F&R trunk and C&S . Vertical MM Rectus abdominis o O: Inf. Surfaces costal cartilages 7-12, thoracolumbar fascia, iliac crest, lat. 1/3rd inguinal lig. o I: Linea alba with aponeurosis of internal oblique, pubic crest, pectineal line via conjoint tendon o NS: Thoracoabdominal nn and first lumbar nn o MA: C&S Pyramidalis - Linea Alba and Rectus sheath: o All flat mm end anteriorly in a strong, flat, sheet-like aponeurosis o Aponeurosis interlace at linea alba (white line) and form the tough, tendinous rectus sheath - Inguinal Canal o Anatomical pathway o Runs in oblique, inferiomedially direction across anterolateral abdominal wall o Open at both ends: . Lateral end: deep inguinal ring - opening in the transversalis fascia . Medial end: superficial inguinal ring – opening in external oblique aponeurosis o Walls: . Anterior wall: aponeurosis of external oblique . Posterior wall: transversalis fascia/conjoint tendon of internal oblique and transverse abdominal mm . Floor: inguinal ligament . Roof: fibres of internal oblique and transverse abdominal mm o Contents: . Male: spermatic cord . Females: round ligament of the uterus/nerves/vessels/lymphatics - Peritoneum: o Consists of: . Parietal peritoneum: Lies in internal surfaces of abdominal and pelvic walls Sensitive to pain, temp, touch, pressure Blood and n supply same as region of wall it lies on . Visceral peritoneum: Covers abdominal viscera .