Anterior Abdominal Wall and Inguinal Region PDF

Anterior Abdominal Wall and Inguinal Canal Reading Assignment: ECA Page 117-130, 132- 135 Body of sternum 4 Costal cartilages 6 Xiphoid process T11 8 12th rib L1 10 Iliac tuberosity Sacral promontory L5 Iliac crest Anterior superior iliac spine Sacrum Coccyx Pubic tubercle Inferior pubic ligament Pu...

Anterior Abdominal Wall and Inguinal Canal Reading Assignment: ECA Page 117-130, 132- 135 Body of sternum 4 Costal cartilages 6 Xiphoid process T11 8 12th rib L1 10 Iliac tuberosity Sacral promontory L5 Iliac crest Anterior superior iliac spine Sacrum Coccyx Pubic tubercle Inferior pubic ligament Pubic arch Wing (ala) of ilium Arcuate line Greater sciatic notch Ischial spine Lesser sciatic notch Pecten pubis pectineal line Anterior Abdominal Wall: Superficial Dissection Fascia of anterolateral abdominal wall From superficial to deep Subcutaneous tissue containing variable amount of fat ▪Below the umbilicus subcutaneous tissue divides into two layers A superficial fatty layer (Camper’s fascia) A deep membranous layer (Scarpa’s fascia) The investing fascia (epimysium) Muscles The endo-abdominal fascia (transversalis fascia) Extraperitoneal fat Parietal peritoneum Rectus sheath Subcutaneous (Superficial fascia) Camper’s fascia Scarpa’s fascia Peritoneal Folds Lat. Umbilical fold The median umbilical fold: extends from the apex of the urinary bladder to umbilicus. Covers the median umbilical ligament The medial umbilical fold covers the medial umbilical ligament formed by occluded parts of the umbilical arteries The lateral umbilical folds cover the inferior epigastric vessels FIGURE 2.2. Subdivisions of abdomen and reference planes. The contents of the quadrants are as follows: Right Upper Quadrant Right lobe of liver, gallbladder, pylorus, the first three parts of the duodenum, head of the pancreas, right suprarenal (adrenal) gland, right kidney, right colic (hepatic) flexure, superior part of ascending colon, right half of transverse colon Left Upper Quadrant Left lobe of liver, spleen, most of stomach, jejunum and proximal ileum, body and tail of pancreas, left suprarenal (adrenal) gland, left kidney, left colic (splenic) flexure, superior part of descending colon, left half of transverse colon Right Lower Quadrant Cecum, appendix, most of ileum, inferior part of ascending colon, right ovary, right uterine tube, right ureter, right spermatic cord Left Lower Quadrant Sigmoid colon, inferior part of descending colon, jejunum and part of ileum, left ovary, left uterine tube, left ureter, left spermatic cord Anterior Abdominal Wall (Intermediate dissection) Linea alba External abdominal oblique muscle Linea semilunaris Inguinal ligament Superficial inguinal ring External abdominal oblique muscle: Origin: Lower eight ribs Insertion: Linea alba, pubic tubercle, and iliac crest Function: flexes and rotates vertebral column, support abdominal viscera, compress the abdominal cavity to increase intraabdominal pressure Tendinous intersection Rectus abdominis muscle Internal abdominal oblique muscle Internal Abdominal oblique, Transversus Abdominis & Rectus Abominis Muscles Internal Abdominal Oblique Origin: Thoracolumber fascia, iliac crest and inguinal lig. Insertion: 10th – 12th ribs, linea alba and pubis via conjoint tendon Transversus abdominis Origin: Thoracolumber fascia, ribs 7th – 12th; iliac crest and inguinal ligament. Insertion: Linea alba, pubic crest via conjoint tendon. Function: The two muscles compress and support abdominal viscera, flex and rotate vertebral column. Innervation: All anterior abdominal wall muscles are innervated by thoracoabdominal (thoracolumber) nerves (T7-T12 and L1) nerves. Rectus abdominis muscle Origin: Pubic symphysis and crest Insertion: Costal cartilages of ribs 5 to 7 and xiphoid process Function: Stabilizes pelvis, flexes vertebral column (antagonize erector spinae muscle and compresses abdominal vicera Anterior layer of rectus sheath [A] Rectus Sheath: Cross section above arcuate line Skin Subcutaneous tissue A Posterior layer of rectus sheath Ext. abd. oblique Int. abd. oblique Transversus abd. [B] Rectus Sheath: Cross section below arcuate line Anterior layer of rectus sheath Transversalis fascia B Rectus abdominis muscles Rectus sheath is formed by the interlaced aponeurosis of the abdominal obliques and transversus muscles The anterior layer is formed by the exernal oblique aponeurosis and the anterior lamina of internal oblique aponeurosis Posterior layer of rectus sheath which ends at the arcuate line is formed by the posterior lamina of the internal abdominal oblique aponeurosis and the transversus abdominis aponeurosis An arcuate line demarcates the transition between the posterior rectus sheath covering the superior 3 quarters of the rectus abdominis proximally and the transversalis fascia covering the inferior quarter Contents of the rectus sheath: rectus abdominis & pyramidalis muscles, superior & inferior epigastric vessels, lymphatics and distal portions of the thoracoabdominal nerves Arteries of Anterior Abdominal Wall Arterial supply to the anterolateral abdominal wall ▪Superior epigastric ▪Musculophrenic ▪Inferior epigastric ▪Deep circumflex iliac ▪Superficial circumflex iliac ▪Superficial epigastric ▪Posterior intercostal ▪Subcostal Superior epigastric off internal thoracic artery and inferior epigastric off external iliac artery anastomose in the rectus abdominis muscle Subclavian a. Axillary a. Internal thoracic a. Superior epigastric a. Musculophrenic a. Inferior epigastric a. Superficial epigastric a. Superficial veins are paired with arteries. Above the umbilicus: Drain into the azygos venous system. Below the umbilicus: Drain into the femoral system (via great saphenous Lateral thoracic vein Portal vein in porta hepatis Lumbar vein Superior epigastric vein Paraumbilical vein Caput Medusae Caput medusae is the appearance of distended and engorged paraumbilical veins, which are seen radiating from the umbilicus across the abdomen to join systemic veins. It is a sign of severe portal hypertension that has decompressed by portal-systemic shunting through the paraumbilical veins Inferior vena cava obstruction Cutaneous Innervation of the Anterior Abdominal Wall Dermatomes Lateral cutaneous branches of intercostal nerves T2-11 Anterior cutaneous branches of intercostal nerves T1-11 Iliohypogastric and Ilioinguinal nerves L1 Anterior Abdominal Wall Hernias Anterior abdominal wall hernias (ventral hernias), are ▪a leading cause of abdominal surgery in the United States ▪involve the protrusion of part of the peritoneal sac through a defect in the muscle layers of the anterior abdominal wall ▪are classified on the basis of their location or cause ▪the major types include incisional hernias, umbilical hernias, paraumbilical hernias, and spigelian (semilunar) hernias ▪With the increasing frequency of abdominal surgery, incisional hernias have become the most common type of anterior abdominal wall hernia ▪incisional hernias occur at sites of weakening along postoperative incisions, usually at the midline Anterior abdominal wall hernias may contain a variety of intraperitoneal structures, including ▪fat, omentum, ▪and bowel. Bowel-containing hernias are particularly important because of potential complications related to ▪incarceration, ▪obstruction, or strangulation of the bowel, ▪ischemia and infarction A B Hiatal hernia: occurs when part of the stomach protrudes into the chest through the diaphragm. Is aggravated by obesity and or smoking Epigastric hernia Boundaries The Inguinal Canal ▪Anterior wall: External oblique aponeurosis ▪Posterior wall: Transversalis fascia ▪Floor: Inguinal ligament ▪Roof : Arched fibres of internal oblique and transversus muscles Contents of inguinal canal ▪Spermatic cord and ilioinguinal nerve in ♂ ▪Round ligament of uterus and ilioinguinal nerve in ♀ Contents of spermatic cord ▪Vas deferens ▪Arteries: testicular, cremasteric, artery to vas deferens ▪Pampiniform plexus of veins ▪Testicular lymphatics ▪Nerves: genital branch of genitofemoral, sympathetic and parasympathetics ▪Processus vaginalis Scrotum and Testes Scrotum is a pendulous purse like arrangement of skin and fascia for the lodgment of testes. The base of the scrotum becomes covered with curly pubic hairs The superficial fascia is totally devoid of fat. Dartos smooth muscle is enclosed within the superficial fascia. Spermatic cord is covered by three layers of fascia & cremaster muscle. Contents of spemartic cord ▪Arteries: testicular artery, deferential artery, cremasteric artery. ▪Nerves: genital branch of genitofemoral nerve to cremaster muscle, sympathetic and parasympathetic nerves ▪Ductus deferens (vas deferens) ▪Pampiniform plexus of veins ▪Lymphatic vessels ▪Tunica vaginalis (remains of processus vaginalis) Inguinal hernia A hernia occurs when part of an organ sticks through a weak point or tear in the thin muscular wall that holds the abdominal organs in place. There are several types of hernias, based on where they occur: Inguinal hernia appears as a bulge in the groin or scrotum. This type is more common in men than women. Femoral hernia appears as a bulge in the upper thigh. This type is more common in women than in men. Hesselbach’s (Inguinal) triangle Boundaries: Medially – lateral border of the rectus abdominis muscle Laterally – Inferior epigastric vessels Inferiorly (base) – Inguinal ligament Hernia Indirect Inguinal Hernia Direct Inguinal Hernia Umbilical Hernia Huge left and right sided indirect inguinal hernia which have entered the scrotum Femoral Hernia Femoral hernias ▪are much more common in women usually elderly and frail, but can occur in men and children. ▪Typically present as a groin lump ▪A weakness in the lower groin allows an intestinal sac to drop into the femoral canal, ▪They may or may not be associated with pain ▪are more prone to develop incarceration or strangulation as an early complication than are inguinal hernias. ▪ has often been found to be the cause of unexplained small bowel obstruction. Femoral hernia Inguinal Canal and the Descent of the Testes Lateral E.P.F Extraperitoneal fascia Medail Lateral Medial Processus vaginalis (Vaginal process) In males, it precedes the testis in their descent down with the gubernaculum, and closes Failure of closure of processus vaginalis leads to: The formation of hydrocele There is the potential for an inguinal hernia to develop. Indirect inguinal hernia? Normal development Persistent patent processus vaginalis more common on the right than the left Compressible deep seated skin colored swelling Hydroceles can be easily demonstrated by shining a flashlight (transillumination) through the enlarged portion of the scrotum. If the scrotum is full of clear fluid, as in a hydrocele, the scrotum will light up. An ultrasound may be done to confirm the diagnosis. Questions?