Abdomen Anatomy 1 تفريغ PDF

Block 1.2 lectures 2024-2025 lecture Highlighter key Writer Reviewer Doctor explanati...

Block 1.2 lectures 2024-2025 lecture Highlighter key Writer Reviewer Doctor explanation Abbreviation Key information Book >> >> Alaa Alessa Ali Aljazeeri 221-222-223 notes References Student explaintion Deleted  Abdomen 1 Dr. Omer Musa Mohamed Musa MBBS, MSc. PHD Assistant Professor Department of biomedical science Anatomy division  Theme 6 Intended learning outcomes: By the end of this session every student should be able to : Describe the anterior abdominal wall surface anatomy and land marks. Describe topography and function of anterolateral wall muscles. Topography ‫دراسة أشكال وأسطح‬ Discuss the rectus sheath anatomy. Know the neurovascular supply of the anterolateral abdominal wall 24/10/2024 2 CONTENTS: Line and land marks of the abdominal surface. Quadrant of the abdomen. Abdominal regions. Skin and fascia. Muscles of the anterolateral abdominal wall. Structure and contents of the Rectus sheath. Neurovascular supply of abdominal wall  The thoracic wall is, mostly, made up of bone (ribcage). While the abdomen is, mostly, made up of muscle (abdominal wall) The Thorax and the abdomen are separated by a barrier, the “Diaphragm.” However, the Abdomen and the pelvis don’t have a structural separating barrier. Therefore, in some textbooks, the abdomen and pelvis are combined, “Abdominopelvic cavity”  There are not many boney landmarks for the abdomen  If we draw both a: Median plane Transumbilical plane the two lines cross each other at the umbilicus, which makes four quadrants of the abdomen This system is simple and has easy to use names. However, it is not very specific and precise  The abdomen is divided into 9 regions by the following planes: Midclavicular planes: Left and right. They end in the middle of the inguinal ligament Subcostal line: the lowest point of costal margin (L3). Intertubercular plane: through tubercles of iliac crests (L5). 1 2 3 4 6 7 8 9 Intertubercular: crosses Two Vertical lines (Midclavicular right and left) Midclavicular: through the Subcoastal: below the through the middle of the Two horizontal lines (Intertubercular and subcostal) middle of the clavicle cartilage of the ribs (costal) hip bones’ iliac tubercules So we have nine regions OTHER IMPORTANT LINE: Transpyloric Planes (L1) : midway between the jugular notch and pubic symphysis (between xiphoid and umbilicus). The transpyloric plans has many organs cross through it Transpyloric: at the first lumbar vertebrae Pylorus: the sphincter after the stomach, before the duodenum We will study it later  Hypo: Below, Chondr: Cartilage Epigastric or epigastrium Famous because of McBurney’s point Hypogastric or Hypogasterium  In comparison to the Quadrant system, it is: More specific (less organs in each region), and Leads to less differential diagnoses (more accurate) Linea alba: Raphe groove / seam Median raphe extends from xiphoid to pubic symphysis. Lies between paired rectus abdominus muscles (fusion of aponeuroses of Aponeuroses flat tendons transversus abdominus, internal oblique, and external oblique). Linea = Line Alba = White During pregnancy, Nigra = Black the Linea Alba turns black, Pubic symphysis is so it is called the the suture at the tip of Linea Nigra the pubis.  Semi: Like/Almost Lunaris: moon / crescent Linea semilunaris: along each lateral border of rectus abdominis. The umbilicus is a scar situated in the linea alba (representing the site of attachment of the umbilical cord in the fetus) Although the umbilicus is not at a fixed position, Arcuate line: Lies midway between umbilicus and pubis. it still is used as a gross anatomical landmark ignore the Arcuate line  The Linea Alba is without any muscle, so surgical incisions of the linea alba (Midline laparotomy) heals much faster than if it were excised through muscle tissue Site of incision: no muscle is affected Linea Semilunaris After surgery, properly stitching will prevent hernias (organs pushing through the abdominal wall). Because, the fascia in Linea Alba is very strong. If done in muscles instead, hernias would be more likely Some surgeries may need to be done not on the linea alba (e.g., appendectomy) Oblique = slanted (neither There is no Deep fascia underneath the Superficial fascia parallel nor perpendicular) (only having superficial allows the abdomen more extension) Fascia = cover of connective Parietal = peritoneum that the three layers of muscle are extensions of the lines muscle ribcage / chest muscles, therefore they are similar 1. Skin. 2. Superficial fascia. 3. Muscles: a. External oblique. b. Internal oblique. c. Transversus abdominis. 4. Extra-peritoneal fascia 5. Parietal peritoneum The gross anatomy is important for knowing where to open the skin during surgeries If we cut through Linea alba we’ll find 4 layers: Skin, Superficial fascia, Extra-peritoneal fascia, Parietal peritoneum (there are no muscles) Therefore, we prefer to do surgery Medially at Linea alba also called (Best line for incision) However, when we reach the umbilicus we do the surgery Laterally (Skirting to the right or left) Parietal Peritoneum  Skin Incision against Langer’s: worse looking healing Incision along Langer’s: better looking healing The two most pinchable areas of skin are: abdominal skin Dorsum (back) of hands Loose attachment to underline structures except Umbulicus ________ Langer’s lines are almost horizontal. Langer’s lines are arrangements of the bundles if possible, cutting along Langer’s lines is better for they are more prominant in females in skin’s connective tissue plastic healing (some cases may need to go against) The superficial fascia It is continuous with, the superficial fascia throughout other regions of the body, it forms two layers: 1- The superficial fatty (Camper's fascia). 2- The deeper membranous layer (Scarpa's fascia). The superficial fascia (Camper's fascia): Contains fat and varies in thickness. It is continuous over the inguinal ligament with the superficial fascia of the thigh and with a similar layer in the perineum. Superficial fascia fat Extraperitoneal fat (Camper fascia) Varied amount of fat Quantity Similar in most people (more in obese people) In some urgent laparotomies, the fat in Function Acts as cutioning Camper’s fascia will need to be drained rapidly for the needed surgery to be done. Histologically Identical Draining isn’t very dangerous. The superficial fascia (Scarpa's fascia): Thin and membranous, and contains little or no fat. Inferiorly, it continues into the thigh, but just below the inguinal ligament, it fuses with the fascia lata. In the midline, it is firmly attached to the linea alba and the symphysis pubis. It is continuous in perineum as Colles' fascia. Later (years from now): we will learn the importance of this continuity  IMPOSRTANT: the things to know relating to muscles are: - Function - Origin - Insertion - Innervation Muscles of the anterior abdominal wall Viscera = peritoneum that Functions: lines organs Protection and stabilization of the viscera Contraction of these muscles assists in both quiet and forced expiration and in coughing and vomiting. Involved in any action that increases intra-abdominal pressure, including parturition, micturition, and defecation. Parturition = giving birth Micturition = urination These functions are constant for all abdominal muscles The white tissue surrounding / covering the muscle is connective tissue called aponeurosis (flattened tendons) The muscles of the anterior abdominal wall Rectus = erect ‫قائم‬ These are of considerable practical importance because their anatomy forms the basis of abdominal incisions. The rectus abdominis arises on a 3 in (7.5 cm) horizontal line from the 5th, 6th and 7th costal cartilages and is inserted for a length of 1in (2.5cm) into the crest of the pubis. The rectus abdominis muscles are not part of the The two rectus abdominal muscles lateral muscles (external, internal, transverse) are parallel to each other but are still important for gross anatomy  5ᵗʰ 6ᵗʰ 7ᵗʰ Vertical Fibers Pubic crest  The rectus abdominis tendinous intersections At the tip of the xiphoid, at the umbilicus and half-way Side note: between them, are three constant transverse tendinous The tendinous intersections are what intersections; below the umbilicus there is sometimes a cause 6-packs to form. For 6-packs to be visible, the fat in fourth. front of the abdomen needs to be These intersections are seen only on the anterior aspect shrank, and the muscles need to be exercised of the muscle and here they adhere to the anterior rectus sheath. Posteriorly they are not in evidence and, in consequence, level of Xiphoid the rectus muscle is completely free behind. Rectus Abdominus Tendinous Because of the intersections being anterior and not posterior, Intersections blood vessels will mostly be being posterior and not anterior. Rectus Abdominus level of umbilicus Possible 4ᵗʰ Tendinous intersection  Very necessary information: the aponeuroses from the three lateral abdominal muscles (external, internal, transverse) go either anterior to or posterior to the rectus abdominis muscles. The aponeuroses (both the anterior and posterior) form the rectus sheath The rectus sheath The rectus sheath is pivotal Because organs are located in to abdominal surgeries relation to it The sheath in which the rectus lies is formed, to a large extent, by the aponeurotic expansions of the lateral abdominal muscles. (A) Above the costal margin, the anterior sheath comprises the external oblique aponeurosis only; posteriorly lie the costal cartilages. (A)All of the sheath is anterior to the rectus muscles Division: Anterior: 1 layer (External oblique only) Posterior: 0 layers  The rectus sheath (B) From the costal margin to a point half-way between umbilicus and pubis, the external oblique and the anterior part of the internal oblique aponeurosis form the anterior sheath. Posteriorly lie the posterior part of this split internal oblique aponeurosis and the aponeurosis of transversus abdominis. Division: Anterior: 1.5 layers Posterior: 1.5 layers Most of the rectus sheath, follow this(B): External oblique: runs anterior to rectus muscles Internal oblique: divides into two parts (half runs anterior other half posterior) Transverse oblique: runs posterior to rectus muscles The internal oblique’s aponeurosis is split in half. one part goes anteriorly to the rectus abdominis muscles, and the other goes posterior. The rectus sheath (C) Below a point half-way between umbilicus and pubis, all the aponeuroses pass in front of the rectus so that the anterior sheath here comprises the tendinous expansions of all three oblique muscles blended together. The posterior wall at this level is made up of the only other structures available, the transversalis fascia and peritoneum.  Division: Anterior: 3 layers Posterior: 0 layers The rectus sheath Arcuate = bow shaped The posterior junction between (b) and (c) is marked by the arcuate line of Douglas, which is the lower border of the posterior aponeurotic part of the rectus sheath. At this point the inferior epigastric artery and vein (from the external iliac vessels) enter the sheath, pass upwards and anastomose with the superior epigastric vessels which are terminal branches of the internal thoracic artery and vein Anastomose = fuse what is written in light gray isn’t important  After the Arcuate line of Douglas, the rectus sheath stops having a posterior wall. the remaining fascia is referred to as ‘transversalis fascia’ The rectus sheath The rectus sheaths fuse in the midline to form the linea alba stretching from the xiphoid to the pubic symphysis. The lateral muscles of the abdominal wall comprise the external and internal oblique and the transverse muscles. They are clinically important in making up the rectus sheath and the inguinal canal, and also because they must be divided in making lateral abdominal incisions. Content of the rectus sheath: The rectus abdominis muscle and pyramidalis muscle (if present) also contains: Ramus = branch the anterior rami of the lower six thoracic nerves. from 7ᵗʰ to 12ᵗʰ rib the superior and inferior epigastric vessels and lymph vessels. IMPORTANT: All abdominal Inside the rectus sheath is: Smooth muscle muscles gain Pyramidalis muscles innervation from (tiny muscles that may be present in some people) Nerve supply the lower 5 Blood supply intercostal nerves (plus the first lumbar, go to slide 60) Lymph drainage  The superior epigastric artery, is branch from internal thoracic artery The inferior epigastric artery, is branch from external iliac artery epigastric Superior The superior and inferior epigastric arteries (and veins also) anastomose (fuse) together epigastric in the rectus sheath. Inferior External oblique The obliquus externus abdominis Xiphoid (external oblique) arises from the Fiber direction in outer surfaces of the lower eight ribs. external oblique: It fans out into insetion the xiphoid, Downwards towards linea alba, the pubic crest, pubic midline tubercle and the anterior half of the iliac crest. From the pubic tubercle to the anterior superior iliac spine its lower border forms the aponeurotic inguinal ligament of Poupart. Inguinal ligament  The external oblique aponeurosis forms: 1. The inguinal ligament Inguinallacunar = in the groin ‫في الحوض‬ = gap ‫تجويف‬ 2. The lacunar ligament 3. The pectineal (Cooper's) ligament Internal oblique The obliquus internus abdominis Fiber direction in (internal oblique) arises from the internal oblique: Upwards towards lumbar fascia, the anterior two- midline thirds of the iliac crest and the lateral two-thirds of the inguinal ligament. It is inserted into the lowest six costal cartilages, linea alba and the pubic crest. The transversus abdominis The transversus abdominis arises Fiber direction in from the lowest six costal Transvers abdominis: transverse cartilages (interdigitating with the diaphragm), the lumbar fascia, the anterior two-thirds of the iliac crest and the lateral one-third of the inguinal ligament; it is inserted into the linea alba and the pubic crest. The external oblique passes downwards and forwards, the internal oblique upwards and forwards and the transversus transversely. Note also that the external oblique has its posterior border free but the deeper two muscles both arise posteriorly from the lumbar fascia. The extraperitoneal fascia It is a connective tissue lies between the transversalis fascia and parietal peritoneum. Containing varying amounts of fat, it is also continuous with a similar layer in the pelvic cavity. It is abundant on the posterior abdominal wall, especially around the kidneys, continues over organs covered by peritoneal reflections. Arteries 1- The superior epigastric artery, one of the terminal branches of the internal thoracic artery supplying the upper central part of the anterior abdominal wall. 2- The inferior epigastric artery is a branch of the external iliac artery just supplying the lower central part of the anterior abdominal wall. 3- The deep circumflex iliac artery is a branch of the external iliac artery supplying the lower lateral part of the abdominal wall. 4-The lower two posterior intercostal arteries, branches of the descending thoracic aorta, and 5-The four lumbar arteries, branches of the abdominal aorta supply the lateral part of the abdominal wall. The arteries correspond to the nine regions (epigastric, hypogastric, lumbar...etc.). abdomen ‫ التي تغذي أعلى الـ‬intercoastal ‫يتبقى فقط الـ‬ Veins: The deep veins correspond to the arteries. Deep Veins The deep veins are: the superior epigastric, inferior epigastric, and deep circumflex iliac veins, follow the arteries of the same name and drain into the internal thoracic and external iliac veins. The lumbar veins drain into the inferior vena cava. Veins: Superficial Veins They form a network that radiates out from the umbilicus. Above, the network is drained into the axillary vein via the lateral thoracic vein and, below, into the femoral vein via the superficial epigastric and great saphenous veins. A few small vein (Paraumbilical veins), connect the network through the umbilicus and along the ligamentum teres to the portal vein. This forms an important portal systemic venous anastomosis.  Caput medusae: engorgement (extreme dilation) of superficial abdominal veins commonly due to portal hypertension Lymph Drainage: Superficial Lymph Vessels Above the level of the umbilicus is upward to the anterior axillary (pectoral) group of nodes. Below the level of the umbilicus, it drains to the superficial inguinal nodes. Deep Lymph Vessels Drain into the internal thoracic, external iliac, posterior mediastinal, and para-aortic (lumbar) nodes. two main lymph vessels: Superficial and Deep Innervation of anterior abdominal wall The anterior rami of the lower six thoracic and the first lumbar nerves. They pass forward in the interval between the internal oblique and the transversus muscles. The thoracic nerves are the lower five intercostal nerves and the subcostal nerves, and the first lumbar nerve is represented by the iliohypogastric and ilioinguinal nerves (branches of the lumbar plexus). There are six nerves (five intercostal, one lumber)  Important dermatome, will come on the test: T7: In the epigastrium, just over the xiphoid process. T10: Around the umbilicus T12: Just above the hypogastric region. L1: At level of symphysis pubis Dermatome = area of skin connected to spinal nerves Innervation of anterior abdominal wall The dermatome of T7 is located in the epigastrium over the xiphoid process, that of T10 includes the umbilicus, and that of L1 lies just above the inguinal ligament and the symphysis pubis.  team Wishes you the best