Abdominal Wall Level 2 PDF

Please note that your main source of studying is your lecture notes. Study well.  Demonstrated by Rana Nady Mostafa. The Abdominal wall. The anterior wall. Digestive system: Anterior Abdominal wall. Abdomen surface anatomy : The abdomen: is the part of the trunk between the th...

Please note that your main source of studying is your lecture notes. Study well.  Demonstrated by Rana Nady Mostafa. The Abdominal wall. The anterior wall. Digestive system: Anterior Abdominal wall. Abdomen surface anatomy : The abdomen: is the part of the trunk between the thorax and the pelvis. There are two ways of dividing the anterolateral abdominal wall: 1) Four quadrants: which are divided by a horizontal trans- umbilical and a vertical median planes. Digestive system: Anterior Abdominal wall. Abdomen surface anatomy : 2) Nine abdominopelvic regions: which are divided horizontally by the superior subcostal plane, which passes right under the costal margins of the 10th ribs , and the inferior intertubercular plane, which connects the tubercules of the iliac crest. Vertically they are divided by the two midclavicular planes. Digestive system: Anterior Abdominal wall. Abdomen surface anatomy : The umbilicus: at the level of the disc between the L3 and L4 vertebrae. Dermatomes: Xiphisternum → T7 Umbilicus → T10 Suprapubic region →T12 Digestive system: Anterior Abdominal wall. Layers of Anterolateral Abdominal Wall: - Skin - Superficial Fascia - Camper's fascia (fatty superficial layer) - Scarpa's fascia (deep fibrous layer) - Muscles - Flat lateral muscles (Obliques & Transverses). - Vertical muscles ( Rectus & Pyramidalis) - Fascia transversalis - Extraperitoneal connective tissue(fat) - Peritoneum What is missing?? Digestive system: Anterior Abdominal wall. The Superficial Fascia: Above the umbilicus: It’s one layer and continues with the body fascia. Below the umbilicus: it’s of two layers: - Camper's fascia (fatty superficial layer) - Scarpa's fascia (deep fibrous layer) it continues below the inguinal ligament to fuse with the deep fascia of the thigh (fascia lata). The superficial vessels and nerves run between these two layers of fascia. Digestive system: Anterior Abdominal wall. Muscles of Anterolateral Abdominal Wall: -3Flat muscles: (Obliques & Transverses). - 2 Vertical muscles ( Rectus & Pyramidalis) Digestive system: Anterior Abdominal wall. Flat lateral muscles: - The External Oblique. - The Internal Oblique. - The Transversus Abdominus Stacked upon each other formed of a fleshy part and an aponeurotic one. Their aponeuroses become entwined in the midline, forming the Linea Alba (a fibrous structure that extends from the xiphoid process of the sternum to the pubic symphysis). Each have a special feature. Digestive system: Anterior Abdominal wall. External oblique: Origin: Outer surfaces of the lower 8 ribs (ribs V to XII). Insertion: - Linea alba - Pubic crest - Pubic tubercle - Anterior 1/2 of the iliac crest (outer lip). Fiber Direction: Inferomedial direction. Digestive system: Anterior Abdominal wall. External oblique: Special features: - The inguinal ligament: formed by the free lower border of the external oblique aponeurosis. It extends between the anterior superior iliac spine laterally and the pubic tubercle medially. - The superficial inguinal ring: an opening in the aponeurosis of the external oblique 1cm above and lateral to the pubic tubercle. - External spermatic fascia: Derived from the aponeurosis of the external oblique muscle. Digestive system: Anterior Abdominal wall. Internal obliques: Origin: - Thoracolumbar fascia. - The intermediate area of the iliac crest. - Lateral 2/3 of inguinal ligament. Insertion: Uppermost fibers → Inferior border of the lower 3 or 4 ribs. Greater part of the muscle → ends in aponeurosis ending in linea alba, Pubic crest & the Pectineal line. Fiber Direction: Upwards, forwards and medially. Digestive system: Anterior Abdominal wall. Internal oblique: Special features: - The Cremaster muscles: Some fibers descends to covers the testes and spermatic cord. - Conjoint tendon. Digestive system: Anterior Abdominal wall. Transversus abdominis: Origin: - Thoracolumbar fascia. - The inner lip of the iliac crest. - Lateral 1/3 of the inguinal ligament. - Inner surfaces of the lower six costal cartilages. Insertion: - Linea alba. - Pubic crest & Pectineal line. Fiber Direction: Horizontally forwards. Digestive system: Anterior Abdominal wall. Transversus abdominis: Special structure: - conjoint tendon: formed by The fusion of the lowest fibers of the internal oblique & the transversus abdominus. It strengthens the abdominal wall at the site where it is weakened by the superficial inguinal ring by the shutter mechanism. Digestive system: Anterior Abdominal wall. The vertical medline muscles: - The rectus abdominus - The pyramidalis. Digestive system: Anterior Abdominal wall. Rectus abdominus: Origin: Lateral head→ from the lateral part of the pubic crest. Medial head→ from the anterior pubic ligament. Insertion: - Costal cartilages of ribs V to VII - Xiphoid process Fiber Direction: Vertically upwards. Digestive system: Anterior Abdominal wall. Rectus abdominus: Special Structure: -Tendinous intersections which are three transverse fibrous bands which divide the muscle into smaller parts. - One lies opposite the umbilicus. - The second opposite the free end of the xiphoid process. - The third in between the two. - linea semilunaris: a surface marking of the lateral border of the muscle. Digestive system: Anterior Abdominal wall. The Pyramidalis: Small triangular muscle lying anterior to the rectus abdominis and enclosed within the rectus sheath. Origin: - Pubic symphysis - Pubic crest. Insertion: The linea alba. Special features: Absent in 20% of the population. Digestive system: Anterior Abdominal wall. Fascia transversalis: - Fascial layer deep to the transversus abdominis muscle. - Separated from peritoneum by extraperitoneal connective tissue. Special structure: - The Deep Inguinal Ring which is an oval opening, the internal opening of the inguinal canal. - The Internal Spermatic fascia of the spermatic cord. Digestive system: Anterior Abdominal wall. Special structures: - The Rectus sheath. - The inguinal canal. Digestive system: Anterior Abdominal wall. Rectus sheath: Multilayered aponeurosis that encloses the rectus abdominis and pyramidalis muscles. formed by a unique layering of the aponeuroses of the external and internal oblique, and transversus abdominis muscles. Digestive system: Anterior Abdominal wall. Rectus sheath: Above the arcuate line: Anterior wall → aponeurosis of the external & internal oblique. Posterior wall →aponeurosis of internal oblique & transversus abdominus. Below the arcuate line: Anterior wall → aponeurosis of the three muscles. Posterior wall → Absent Digestive system: Anterior Abdominal wall. Rectus sheath: Contents: Muscles → The rectus abdominis and pyramidalis muscle. Vessels → superior & inferior epigastric arteries & veins. Nerves → lower 5 intercostal nerves (T7-T11) & termination of the T12 thoracic nerve. Digestive system: Anterior Abdominal wall. Inguinal canal: The inguinal canal is a short passage (about 4 cm) that extends inferiorly and medially through the inferior part of the abdominal wall. It is superior and parallel to the medial ½ of the inguinal ligament. It forms a passageway for male gonads from the abdomen to the scrotum allowing its descend. It extends between the deep inguinal ring (at the fascia transversalis) to the superficial inguinal ring (at the external oblique aponeurosis). Digestive system: Anterior Abdominal wall. Inguinal canal: Rings: Deep (internal) ring: oval shaped opening at the transversalis fascia above the midpoint of the inguinal ligament (lateral to the epigastric vessels). Superficial (external) ring: Triangle shaped opening at the external oblique just 1 cm above & lateral to the pubic tubercle. It’ bounded by crura to prevent its widening. Digestive system: Anterior Abdominal wall. Inguinal canal: Walls: Anterior wall → aponeurosis of the external oblique, reinforced by the internal oblique muscle laterally. Posterior wall → transversalis fascia reinforced medially by the conjoint tendon. Roof → transversalis fascia, internal oblique, and transversus abdominis. Floor → medial ½ of the inguinal ligament (a ‘rolled up’ portion of the external oblique aponeurosis), thickened medially by the lacunar ligament. Digestive system: Anterior Abdominal wall. Inguinal canal: Contents: - The spermatic cord in males, or the round ligament of the uterus in females. - The ilioinguinal nerve: contributes towards the sensory innervation of the genitalia and only travels through part of the inguinal canal, exiting via the superficial inguinal ring. - Genital branch of the genitofemoral nerve: supplies the cremaster muscle and anterior scrotal skin in males, and the skin of the mons pubis and labia majora in female. Digestive system: Anterior Abdominal wall. Inguinal canal: Spermatic cord notes: Fascial Coverings: The contents of the spermatic cord are mainly bound together by three fascial layers. They are all derived from anterior abdominal wall: External spermatic fascia – derived from the aponeurosis of the external oblique muscle. Cremaster muscle and fascia – derived from the internal oblique muscle. Internal spermatic fascia – derived from the transversalis fascia. The three fascial layers themselves are covered by a layer of superficial fascia, which lies directly below the scrotal skin. Digestive system: Anterior Abdominal wall. The peritoneum: It’s a thin membrane lines the walls of the abdominal cavity (partial layer) and covers much of the viscera ( visceral layer) Peritoneal cavity: Is a potential space between the parietal and visceral layers of peritoneum. It contains a thin film of serous fluid allows free movement of one peritoneal surface over another. Abdominal viscera are either suspended (intraperitoneal) in the peritoneal cavity by folds of peritoneum or are outside (retroperitoneal) the peritoneal cavity.