Abdomen Anatomy Notes PDF

M.B.Ch.B. M.Sc. Ph.D. Anatomy 24/10/2023 1  Learning Objectives 1. Define the boundaries of the abdomen and the abdominal wall. 2. Describe the Abdominal cavity 3. Define the Groin (Inguinal region) 4. Describe the Anatomy of Abdomina...

M.B.Ch.B. M.Sc. Ph.D. Anatomy 24/10/2023 1  Learning Objectives 1. Define the boundaries of the abdomen and the abdominal wall. 2. Describe the Abdominal cavity 3. Define the Groin (Inguinal region) 4. Describe the Anatomy of Abdominal viscera: (Peritoneum, stomach, small and large intestines, liver, pancreas, spleen, kidneys and ureters) 5. Illustrate the abdominal Blood Vessels, portal system and Innervation 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 2  ABDOMEN The abdomen is a cylindrical chamber extending from the inferior margin of the thorax to the superior margin of the pelvis and the lower limb. The inferior thoracic aperture forms the superior opening to the abdomen, and is closed by the diaphragm. Inferiorly, the deep abdominal wall is continuous with the pelvic wall at the pelvic inlet. Superficially, the inferior limit of the abdominal wall is the superior margin of the lower limb. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 3  Functions 1. Houses and protects major viscera. 2. Breathing 3. Changes in intra-abdominal pressure assist in voiding of abdominal contents, like bladder, rectum and giving birth. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 4  Abdominal Wall It consists mainly of muscles and partly of bones. Bony skeleton consists of: 1. Five lumbar vertebrae 2. Upper parts of the hip (Ilium) 3. Inferior thoracic aperture (Xiphoid process, costal margins and lower two ribs). 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 5  Abdominal Wall Muscles make up the rest of the abdominal wall: 1. Anteriorly: Rectus abdominis 2. Laterally: three layers of muscles; external oblique, internal oblique and transversus abdominis 3. Posteriorly: quadratus lumborum, psoas major and iliacus 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 6  Abdominal Wall The layers of the abdominal wall consist of: a. Skin b. Superficial fascia (subcutaneous tissue) c. Deep fascia d. Muscles e. Extra-peritoneal fascia f. Parietal peritoneum 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 7  Single fatty layer of subcutaneous tissue above umbilicus. Double layers below umbilicus; superficial fatty layer (Camper’s fascia) of variable thickness, continuous over the inguinal ligament with the superficial fascia of the thigh and with a similar layer in the perineum. The deeper membranous layer (Scarpa’s fascia) is thin and contain little or no fat, continues into the thigh, but just below the inguinal ligament, it fuses with the deep fascia of the thigh (the fascia lata). 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 8  There are three flat muscles laterally and one vertical muscle anteriorly. Functions: 1. Form a firm, but flexible, wall that keeps the abdominal viscera within the abdominal cavity 2. Protect the viscera from injury 3. Help maintain the position of the viscera in the erect posture against the action of gravity. 4. Assist in both quiet and forced expiration. 5. Assist in abdominal voiding. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 9  Superficial muscle, has inferomedial direction of fibers. Originates from lower eight ribs. In midline, it has large aponeuroses twisted forming linea alba, which extends from the xiphoid process to the pubic symphysis. The lower border of the external oblique aponeurosis forms the inguinal ligament on each side. It folds under itself forming a channel, which plays an important role in the formation of the inguinal canal. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 10  The second layer of abdominal muscles, it is smaller and thinner than external oblique. Its fibers run in superomedial direction to end in the midline as aponeurosis blend with Linea alba. Originates from iliac crest and inguinal ligament to be inserted in lower 3 or 4 ribs, linea alba and pubic crest. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 11  Deep to the internal oblique muscle. It has horizontal fibers from iliac crest, lower six ribs and inguinal ligament, to linea alba and pubic crest. All these muscles are innervated segmentally by the intercostal nerves T7- T12 and L1. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 12  Long, flat muscle extends along the anterior abdominal wall. It is a paired muscle, separated in the midline by the linea alba, and it widens and thins as it ascends from the pubic symphysis to the costal margin. Along its course, it is intersected by three or four transverse fibrous bands or tendinous intersections. These are easily visible on individuals with a well- developed rectus abdominis. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 13  Second vertical muscle in the anterior abdominal wall. It is small, triangular-shaped muscle, which may be absent, is anterior to the rectus abdominis, has its base on the pubis, and its apex is attached superiorly and medially to the linea alba. It tenses the linea alba. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 14  Aponeurotic tendinous sheath formed by aponeuroses of the three lateral abdominal muscles enclosing completely the upper three quarters of rectus abdominis, and only anteriorly in the lower quarter. The anterior wall consists of the aponeurosis of the external oblique and half of the aponeurosis of the internal oblique, which splits at the lateral margin of the rectus abdominis 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 15  The posterior wall of the rectus sheath consists of the other half of the aponeurosis of the internal oblique and the aponeurosis of the transversus abdominis. As no sheath covers the posterior surface of the lower quarter of the rectus abdominis muscle, the muscle at this point is in direct contact with the transversalis fascia. Marking this point of transition is an arch of fibers (the arcuate line) 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 16  Connective tissue layer deep to transversalis fascia, separates it from the peritoneum. It lines the abdominal cavity as well as the pelvic cavity. It is abundant on the posterior abdominal wall, especially around the kidneys, continues over organs covered by peritoneal reflections. Viscera in the extraperitoneal fascia are referred to as retroperitoneal. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 17  It is thin serous membrane lines the walls of the abdominal cavity and, at various points, reflects onto the abdominal viscera, providing either a complete or a partial covering. The peritoneum lining the walls is the parietal peritoneum; the peritoneum covering the viscera is the visceral peritoneum. The continuous lining of the abdominal walls by the parietal peritoneum forms a sac called the peritoneal cavity. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 18  The skin and muscles of the anterolateral abdominal wall are supplied by T7 to T12 and L1 spinal nerves. Branches of L1 (the iliohypogastric nerve and ilio-inguinal nerve), which originate from the lumbar plexus, follow similar courses initially, but deviate from this pattern near their final destination. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 19  Superficially The superior part of the wall is supplied by branches from the musculophrenic artery, a terminal branch of the internal thoracic artery The inferior part of the wall is supplied by the medially placed superficial epigastric artery and the laterally placed superficial circumflex iliac artery, both branches of the femoral artery 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 20  At a deeper level: The superior part of the wall is supplied by the superior epigastric artery, a terminal branch of the internal thoracic artery. The lateral part of the wall is supplied by branches of the 10th and 11th intercostal arteries and the subcostal artery. The inferior part of the wall is supplied by the inferior epigastric artery and the deep circumflex iliac artery, both branches of the external iliac artery. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 21 ▪ Superficial lymphatics above the umbilicus pass in a superior direction to the axillary nodes, while drainage below the umbilicus passes in an inferior direction to the superficial inguinal nodes. ▪ Deep lymphatic drainage follows the deep arteries back to parasternal nodes along the internal thoracic artery, lumbar nodes along the abdominal aorta, and external iliac nodes along the external iliac artery. 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 22  ▪ Surgical Incisions 24/10/2023 Email :[email protected] Website :http://Alkafeel.edu.iq 23 1. Gray’s Anatomy for Students. 2. Clinical Anatomy by Regions. Richard S. Snell. 3. Clinically Oriented Anatomy. Keith L. Moore. Email :[email protected] Website :http://Alkafeel.edu.iq