Anterior Abdominal Wall Anatomy PDF

Anterior Abdominal Wall & Inguinal Canal Intended learning outcomes At the end of this lecture student should be able to describe o Layers of the anterior abdominal wall o Blood and nerve supply of the anterior abdominal wall o Rectus sheath o Inguinal canal o Clinical correlations Abdominal...

Anterior Abdominal Wall & Inguinal Canal Intended learning outcomes At the end of this lecture student should be able to describe o Layers of the anterior abdominal wall o Blood and nerve supply of the anterior abdominal wall o Rectus sheath o Inguinal canal o Clinical correlations Abdominal regions oDivided into 9 regions by two pairs of planes: Vertical Planes: Left and right lateral planes midclavicular planes Horizontal Planes: Transpyloric plane: Midway between jugular notch and pubic symphysis (between xiphoid and umbilicus). Intertubercular plane: Through tubercles of iliac crests.  Layers of the anterior Abdominal Wall oSkin oSuperficial fascia oMuscles oTransversalis fascia oExtra-peritoneal fat oParietal peritoneum Superficial Fascia o Superficial fatty layer Camper’s fascia contains superficial vessels-mainly veins- and cutaneous ? ? nerves) o Deep membranous layer Scarpa’s fascia deep to Camper’s f. o It is continuation in the perineum referred to as colles fascia  Muscle of the anterior abdominal wall o General Characteristics: Three large flat sheets connecting rib cage to hip bone. o Muscular posteriorly and laterally. o Aponeurotic anteriorly and medially. Muscle of the ant abd wall oInclude: oExternal oblique. oInternal oblique. oTransversus abdominus. oRectus abdominus. oPyramidalis. External oblique. External Abdominal Oblique (EAO) Rectus Sheath [RS] (Lateral margin=semilunar line of Douglas Midline= linea alba & at the vertebral level R of L4 the umbilicus) S Spermatic cord or Round ligament of the Uterus (exiting superficial inguinal ring) Susensory ligament of the penis or clitoris Inguinal Ligament o Inguinal ligament: Thickened lower border of external oblique aponeurosis. o Extend From anterior superior iliac spine to pubic tubercle. o Medial end extend backward and upward to the pectineal line to form lacunar ligament  Inferior Lumbar or Petit’s Triangle o Inferior border-iliac crest o Lateral border-external abdominal oblique m o Medial border-latissimus dorsi m o Site of rare lumber hernia  Internal abdominal oblique AND rectus sheath EAO removed removed exposing (cut edge of EAO) rectus abdominis internal abdominal oblique m  Superior Lumbar or Grynfeltt’s Triangle (Most common site of a lumbar hernia) o Superior border- 12th rib o Medial border-iliocostalis m o Lateral border- internal abdominal oblique m Transversus abdominus. Transversus abdominus rectus abdominis Pyramidalis Linea Alba Median raphe Extends from xiphoid to pubic symphysis. Lies between paired rectus abdominus muscles. fusion of aponeurosis of Transversus abdominus, internal oblique, and external oblique. Rectus sheath Superior epigastric vessels Rectus abdominus Arcuate line Inferior epigastric vessels EAO IAO RA TA Above Arcuate Line TF EPT EAO PP IAO TA RA TF EPT Below Arcuate Line PP Contents of the rectus sheath o Rectus m o Superior epigastric vessels o Inferior epigastric vessels o Terminal parts of the lower thoracic nerves Action od abdominal muscles o Move the trunk o Depress the ribs during expiration o Compress abdomen (abdominal straining and lifting weights) o Support abdominal viscera Blood supply of Abdominal Wall o Superior epigastric A o Inferior epigastric A o Deep circumflex iliac A o Superficial circumflex iliac A o Superficial external Pudendal A internal thoracic a. musculophrenic a. superior epigastric a. inferior epigastric a. superficial circumflex iliac a.  ? superior epigastric v. thoracoepigastric v. ? inferior epigastric v. superficial epigastric v. Nerve supply of the anterior abdominal wall o Ventral rami of T7 to T12 o Ili-hypogastric nerve L1 o Ilio-inguinal nerve L1 Inguinal region Inguinal canal o Oblique intramuscular canal lies just above the inguinal ligament o 4 cm long o Extend between superficial and deep inguinal rings o Has anterior, posterior wall, roof and floor  Superficial ring Medial Crus Lateral Crus Intercrural fibers Superficial Inguinal Ring Spermatic cord Deep inguinal ring deep inguinal ring testicular vessels vas deferens ? deep inguinal ring testicular vessels subinguinal hiatus vas deferens  spermatic cord spermatic cord round ligament of the uterus attaching to labium majorum (removed)  Indirect inguinal o Traverses deep and superficial inguinal rings and inguinal canal. o Lies within coverings of spermatic cord. May descend into scrotum. More common than a direct inguinal hernia. More common in boys and young men. May be congenital. Direct inguinal o Occurs in older men (rarely women). Due to weakness in abdominal wall o Behind or lateral to superficial inguinal ring (Hesselbach’s Triangle) o Passes directly through abdominal wall to superficial inguinal ring. o Does not extend into scrotum. o Has sac formed by peritoneum.