-2 ة يمجع وبأ اه م - - Dr Muhtaseb Al - 1

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1 -2 م ها أبو عجمي ة - - Dr Al - Muhtaseb 1

2 Refer to Snell for clinical notes (as the doctor said in his first lecture O_O) and to the slides for illustrations. This sheet is about abdomen, there are anterior and posterior abdominal walls The posterior abdominal wall is formed by the lower five lumbar vertebrae, bones and muscles originating from the back, but today we will talk about the anterior abdominal wall. Let s have some definitions (you can skip) Let s start - Aponeurosis (many aponeuroses): flattened tendon serves as attachment to flat muscles -either origin or insertion-. - Viscera: the internal organs in a body cavity - the difference between the visceral peritoneum and the parietal peritoneum? the parietal peritoneum: covering the abdominal cavity. we can t reach any organ in the abdomen without incising the parietal peritoneum. the visceral peritoneum: adherent to the viscera (the organs), the viscera cover the abdominal cavity (parietal peritoneum is then the membrane which covers the abdominal viscera While the visceral peritoneum is adherent to the viscera. Abdomen: is the region of the trunk that lies between the diaphragm above and the inlet of the pelvis below - ABOVE, it is formed by the diaphragm which separates the abdominal cavity and the thoracic cavity, The diaphragm has right and left domes (also known as cupolae). We should know what is found above the right cupola and what is below it Below the right cupola, we find the liver, usually pushes the right cupola upward until it reaches the 5 th intercoastal space Above in the chest, the base of right pleura Above the left cupola, we find the left pleura of lung Below the left cupola, we find the spleen 2

3 - BELOW, no separation here, the abdominal cavity is continuous with the pelvic cavity through the pelvic inlet, until reaching the iliac crest, the line between the left and right iliac tubercles separates abdomen and pelvis There are some structures that are found in both the abdomen and pelvis (such as descending colon, rectum and anal canal, they all start at abdomen and ends at pelvis) We conclude that the abdomen is not separated from pelvis, but then, a boundary between them is formed by the iliac crest Borders - Superiorly (Anterior Border): lower Costal cartilages (7-12 ribs, remember that both 11 and 12 have no coastal cartilages) Xiphoid process (at the end of sternum) - Inferiorly (Anterior Border): Pubic bone -symphysis pubis- iliac crest (at the Level of L4.) - Umbilicus: an important landmark, (Level of intervertebral disc L3-L4) Areas of the abdomen There are many organs (viscera) in the abdomen, like those of the digestive system, in order to locate each organ; the abdominal area is divided into four quadrants, formed by two intersecting lines (Vertical & Horizontal Intersect at umbilicus): 1) Upper left 2) Upper right 3) Lower left 4) Lower right This has a great clinical importance, (doctors usually use these anatomical terms) let s have some examples, 3

4 1) if a patient complains of severe pain in his lower right quadrant, one of the most common, possible diagnoses is acute appendicitis, because appendix is found there (the right iliac fossa) and when doctors make sure by blood tests, surgeons will hence perform appendectomy to relieve pain. (differential diagnoses: ascending colon and cecum too) 2) If a 40-year old woman feels pain in the right upper quadrant, her doctor will think of cholecystitis because the upper right quadrant is where the gall bladder exists (liver too) But the four quadrants method is outdated, and there is a new, more accurate method which is known as the nine areas. The abdomen is divided into 9 regions by four imaginary planes/ lines Two Vertical Planes: (left and right Midclavicular planes) They extend from the midpoint of each clavicle, to the midpoint between pubic symphysis and anterior superior iliac spine (midinguinal point) Two Horizontal Planes: Upper Subcostal plane: - this plane lies at the level of L3 - Joins the lower end of costal cartilage on each side, (Below the costal cartilage, more precisely, below the costal cartilage number 9.) Lower Intertubercular plane: At the level of L5 vertebra, between the two right and left iliac tubercles of the hip bone. The names of the regions: i. First row: o Right hypochondriac region (below ribs/ the costal cartilage) you find: the right lobe of the liver the gall bladder. o Left hypochondriac region (below ribs/ the costal cartilage), you find: 4

5 the spleen. (the spleen is a reservoir of blood, any trauma can cause bleeding). o Epigastric region (above the stomach), you find: the stomach the left lobe of the liver. ii. Second row: o Umbilical region (in the middle, around the umbilicus), the small intestines are deep to it o Right lumbar region (ascending colon). o Left lumbar region (descending colon). (The kidneys lie in the posterior part of the right and left lateral lumbers) iii. Third row: o The suprapubic/ the hypogastric region (below the stomach) : it is where we find the urinary bladder and urethra. o Right iliac (inguinal) region (where you find the cecum and the appendix) o Left iliac (inguinal) region - Related to the inguinal canal (the spermatic cord in males and ovaries in females) NOTES: you have to be able to differentiate between appendicitis and menstrual pain in females The appendicitis` pain starts around the umbilicus, because there is a dermatome around it, then the pain moves to the lower right of the abdomen. Another clinical application: inguinal hernia might take place here Anterior abdominal wall What are the Layers of Anterior Abdominal Wall? (skin/ superficial fascia -subdermal- / (deep fascia) /transversalis fascia/ extraperitoneal/ parietal peritoneum -simple squamous epithelial layer- 5

6 These layers are very important, surgeons! 1. Skin 2. Superficial Fascia : o Above the umbilicus (one fatty layer). Scarp's fascia. o Below the umbilicus two layers (fatty and membranous layers) I. Camper's fascia - fatty superficial layer. In males scrotum, the continuation of this camper s layer is a muscle that is called dartos muscle under the skin meaning that the abdominal wall descends to the perineum. II. Scarpa's fascia - deep membranous layer, it attaches to the fascia lata below the inguinal ligament in the lower limb. It is continuous into the perineum, it attaches to the pubic arch at both sides, and posteriorly to the perineal body. Attachment of scarpa s fascia= Inf: Fascia lata Sides: Pubic arch Post: Perineal body (The membranous fascial layer in the scrotum, has an extension called COLLE`S FASCIA.) What is the perineal body? o It is a fibrous structure anterior to anus (between the anal orifice and the symphysis pubis anteriorly??). Clinical point on the scarp`s fascia: rupture of penile urethra leads to extravasations of urine: - Around scrotum and penis - Around perineum - lower abdomen (below the umbilicus, where membranous layer is found) - above the fascia lata. LUCKILY, this happens because of the continuous scarp s fascia attachment, if not attached, the urine would possibly reach the lower limb 6

7 3. Deep fascia: - a layer of connective tissue covering the muscles, - it is very thin, and may be absent in some people, especially in women, because deep fascia resists the abdomen enlargement, thus it is absent in women to allow the enlargment of the uterus forward and upward during pregnancy Before talking about the muscular layer, let s talk about linea alba because it serves as an insertion point to all these abdominal muscles or linea alba: a fibrous connective tissue, it extends along الخط األبيض the midline, from the xiphoid process to symphysis pubis, it is formed by the fusion of aponeuroses of three abdominal wall (Ex. In, Tran. Abd. muscles) it has little supply of blood, it is important surgically, because midline incisions are usually performed there, and this has some advantages and disadvantages, - Advantages: o Good access to both sides of the abdomen, In case of tumors in the abdomen for example, or any other purpose that requires wide opening of the abdomen, a midline incision in the linea alba could be a good option. o less bleeding, because it is fibrous. - Disadvantages: o Postsurgical healing process is poor and takes long time, because of poor blood supply. In addition to midline incision, there are other types of abdominal incisions: Rectus sheath/ pararectal (Battle s incision)/ Transverse and many others 4. Muscular layer, we have four muscles, All the abdominal muscles insert themselves in the linea alba, by their aponeuroses, (from the most superficial to the deepest, 1) external abdominal oblique 2) Internal abdominal oblique 3) transversus A) External oblique muscle (external abdominis muscle) It is a thin, broad muscle that comes from the back and extends in an oblique fashion -> the fibers run obliquely downward forward 7

8 and medially (analogous to someone s hands in the pockets of their pants) a. Origin: outer surface of lower 8 ribs b. Insertion: - Xiphoid process, Linea alba - Pubic crest and Pubic tubercle, and it reaches Iliac crest (anterior half) c. Nerve Supply: -T7 -T12 (Lower 6 thoracic/intercostal nerves) -L1 ( iliohypogastric nerve, ilioinguinal nerve). d. Muscle s Contributions The muscular part of External oblique becomes aponeurotic (aponeurosis) before reaching linea Alba, the aponeurosis of this muscle contributes to: i. Inguinal ligament: folding of the lower border of aponeurosis of the external oblique muscle on itself, extends between anterior superior iliac spine and pubic tubercle. ii. Lacunar ligament: reflection of inguinal ligament, it forms the medial boundary to the femoral canal. Slides: extension of aponeurosis of external muscle backward and upward to the pectineal line, on the superior ramus of the pubis, its sharp, free crecentric edge forms the medial margin of the femoral ring iii. Pectineal ligament: (aka, Cooper ligament) reflection of inguinal ligament and it is the continuation of lacunar ligament at pectineal line and continues with a thickening of the periosteum iv. Superficial inguinal ring, - it is a defect in external oblique aponeurosis, - it lies above and medial to the pubic tubercule - this ring is triangular in shape and it has medial crus/ lateral crus.. - it transmits structures of the female and male inguinal canal such as the round ligament of uterus (females) and spermatic cord (males) w its associated nerves, blood vessels, vas deferens.. - it contributes in the spermatic cord coverings (external spermatic fascia) 8

9 v. the anterior layer of rectus sheath vi. it also contributes to the boundaries of the inguinal canal, which is found between deep and superficial inguinal rings ExtraNote: (you can skip) lat er al crus of the su per fi cial in gui nal ring (portion of the external oblique aponeurosis that passes lateral to the superficial inguinal ring blending into the inguinal ligament and forming the lateral boundary of the ring. me di al crus of the su per fi cial in gui nal ring : portion of the external oblique aponeurosis that passes medial to the superficial inguinal ring forming the medial boundary of the ring. B) Internal oblique muscle (deep to external oblique muscle, its fibers run upward forward and medially) a. Origin Lumbar Fascia, Anterior 2/3 of iliac crest, lateral 2 /3 of inguinal ligament. b. Insertion: Lower three ribs and costal cartilage, Xiphoid process, Symphysis pubis (Linea alba) c. Nerve Supply: (like external oblique) Lower 6 thoracic nerves, and iliohypogastric nerve &ilioinguinal nerve (L1). d. Muscle s Contributions, i. Cremasteric muscle and fascia, Internal oblique has free lower border arches over the spermatic cord or ligament of uterus The spermatic cord and testes (in males) are covered by cremasteric fascia. This Cremasteric Fascia is Related to the Inguinal Canal ii. this muscle assists in the formation of the roof of the inguinal canal iii. Conjoint tendon, o combined fibers of internal oblique and transversus abdominis muscles. o The conjoint tendon is -inserted on- the pubis. o Attached medially to linea alba supporting the inguinal canal 9

10 o Has lateral free border (فتق It is important to take stitches in herniorrhaphy (in inguinal hernia because it is very strong tendon iv. It contributes to layers of the rectus sheath. C) Transversus abdominis muscle, as the name implies, its fibers run transversely (horizontally). i. Origin: (from back) lumbar fascia, lower 6 costal cartilage, anterior 2 thirds of the iliac crest, the lateral one third of the inguinal ligament. ii. Insertion: linea alba (the xiphoid process to symphasis pubis.) iii. Nerve supply : Lower 6 thoracic nerves, L1 (illiohypogastric and illioinguinal nerves) iv. Muscle s contributions, (with the internal oblique muscle s fibers, it forms the conjoint tendon. which attaches to pubic crest and pectineal line) and (contributes to the layers of rectus sheath) - NoTE: The collection of the abdominal muscle fibers (downward, upward, transverse) make a very strong network, thus the abdominal muscles are very strong muscles. (protection of the abdominal viscera). let s talk about the muscular contents of rectus sheath in detail.. D) Rectus abdominis muscle Rectus abdominis is a long strap muscle, it extends along the whole length of the anterior abdominal wall and it differs from the previously mentioned muscles in many aspects: 10

11 It is found inside the rectus sheath (between the linea alba and the semilunaris.) It has tendinous intersections (they are adherent to rectus sheath, anteriorly) No L1 nerve supply the rectus abdominis is colloquially called abs ("six-pack" :P). (it is divided into squares according to the record) This is due to tendinous intersections, which are 3 transverse fibrous bands (can be palpated as a transverse depressions) these tendinous intersections divide the rectus abdominis muscle into distinct segments, 1- at level of xiphoid process 2- at level of umbilicus 3- one half way between these two In embryos, these tendinous intersections come from myotome, then continue as a separated myotome because of the tendons. v. Origin: (lower part) symphysis pubis and pubic crest vi. Insertion: upwards in the 5th,6th,7th costal cartilage and the xiphoid process. (linea alba) vii. Nerve supply: lower 6 thoracic nerves. (but NOT L1) E) Pyramidalis muscle: - It lies in front of the lower part of the rectus abdominis muscle - May be absent - Inside the rectus sheath in the lower part ( if present). - Used surgically as reconstructive muscle (in addition to assisting abdominal muscles in their actions) o Origin: from the anterior surface of the pubis. o Insertion: linea alba. o Action: pulls linea alba. o Nerve supply: 12th subcoastal nerve ( the last intercostal N.) 5. Transversalis fascia: 11

12 thin layer of fibrous connective tissue covering the muscles, continues to diaphragm, iliac muscle and pelvis, Found in the posterior wall of the rectus sheath, below the anterior superior aliac spine we ve talked about this fascia (in the MSS System) we said it forms the anterior wall of femoral sheath - remember: posterior wall of femoral sheath is formed by the fascia iliaca Transversalis fascia contributions: - femoral sheath - the posterior layer of rectus sheath - deep inguinal ring and thus a fascia that covers the spermatic cord (internal spermatic fascia) 6. Extraperitoneal fascia - usually it is in the form of adipose tissue(fat). - Located above the parietal peritoneum, and below the transversalis fascia. 7. Parietal peritoneum: It is a thin serous membrane, Continuous below with the parietal peritoneum lining the pelvis. It covers the abdominal cavity, we incise it to reach abdominal viscera (it is then a lining for the abdomino-pelvic cavity) So when a doctor wants to make a surgery in the stomach, the layers that he/she d face are : skin, superficial fascia, (deep fascia if present), the muscles, transversalis facia, extraperitoneal, parietal peritoneum, then the visceral peritoneum (which is adherent to viscera, e.g: stomach). Blood supply of the Anterior Abdominal Wall (from slides) - Arterial Supply Sup. Epigastric artery Inf. Epigastric artery Intercostal arteries Lumbar arteries Deep circumflex artery 12

13 Note: superior epigastric (a branch of internal thoracic artery) Inferior epigastric and deep circumflex iliac artery (branches of external iliac artery) - Venous Supply Below the umbilicus Inferior (superficial) Epigastric - <Femoral vein Superficial, meaning that the superficial epigastric empties into femoral vein Above the umbilicus - Lat. Thoracic. vein. <Axillary vein Paraumbilica veins - Ligamentum teres < portal vein(portosystemic anastomosis - Lymphatic drainage of ant. Abdominal wall (from slides) Above the umbilicus: Ant.axillary L.N Below the umbilicus: Sup. Inguinal L.N Above the iliac crest: Post.axillary.L.N Below the iliac crest: Sup.inguinal L.N Innervation of the Anterior Abdominal Wall - Thoracoabdominal nerve: Lower 6th thoracic nerves & 12th subcostal nerve - Dermatomes (Anterior, lateral cutaneous nerve terminal branches of Thoracoabdominal nerve T7 to skin superior to umbilicus below xiphoid process T10 to skin surrounding umbilicus L1 to skin inferior to umbilicus above sym.pubis - LI nerve - Iliohypogastric nerve+ ilioinguinal nerve Note: The lumbar triangle in not required. Fasciae of the anterior Abdominal wall: - Rectus sheath - Transversalis fascia: - extraparietal fascia: - Parietal peritoneum 13

14 The Rectus Sheath The rectus sheath is a long fibrous sheath Formed mainly by the aponeuroses of the three lateral abdominal muscles. The rectus sheath starts from linea semilunaris and fuses (ends) in the linea alba Semilunaris: the lateral border of rectus abdominis muscle This muscle has tendinous intersections attached to the anterior wall of the rectus sheath (not the posterior, it is separated from the wall posteriorly). It can be palpated and it extends from 9th c.c to the pubic tubercle Extra note: it is a bilateral feature (right&left) The rectus sheath is formed by the aponeuroses of the transverse abdominal and the external and internal oblique muscles. but It contains the rectus abdominis (and pyramidalis muscle if not absent) It has anterior and posterior wall Formed by the aponeurosis of the abdominal muscles (external and internal oblique muscles and transversus abdominis muscle) Anteriorly, tendinous intersections of the rectus abdominis muscle, these intersections are adherent (firmly attached) to rectus sheath but posteriorly, the posterior wall of the rectus sheath is not attached to the rectus abdominis muscle, meaning that you can put your hand between the muscle and this wall of the sheath Its Contents a. Lower six thoracic nerves (The anterior rami of the lower six thoracic nerves b. Lymphatic vessels c. Two muscles: rectus abdominis and pyramidalis. d. two arteries: inferior epigastric (a branch from external iliac) superior epigastric (a branch from internal thoracic artery which is branch from a subclavian artery which comes from the brachiocephalic artery ). There is an anastomosis between these two arteries inside the rectus sheath around the umbilicus, and 14

15 they separate the rectus abdominis muscle from the posterior layer. e. Rectus sheaths, We have one at left and one at right, separated by linea alba. In other words, linea alba separates the right and left rectus abdominis muscles. f. Description the rectus sheath is considered at three levels but, always the same contents: (refer to slides ) A) Above costal margin (5th,6th and 7th) and xiphoid process: (look at figure A) - The anterior wall: skin, superficial fascia, aponeurosis of external oblique muscle. - Posterior Wall : costal cartilage number 5,6 and 7, then intercostal muscle, and xiphoid process in the front (Content: rectus abdominis muscle.) B) Below costal margin, (between the costal margin and anterior Superior iliac spine ASIS): (important) Midway between umbilicus&xiphoid and Midway between umbilicus&symphysis pubis: As you can see from figure B in the slides, the internal oblique muscle splits to enclose the rectus abdominis muscle, part of it contributes to the anterior wall and the other part contributes to the posterior wall - Anterior Wall: the aponeurosis of external oblique and one layer of internal oblique. - Posterior Wall: one layer of internal oblique aponeurosis and transversus abdominis aponeurosis. (Contents: rectus abdominis muscle (it is enclosed by the 2 layers of internal oblique)). C) Below ASIS anterior superior Iliac spine (below Midway between umbilicus and symphysis pubis): (look at figure c) The inferior epigastric artery enters the rectus sheath below the arcuate line, and the arcuate line is a very important landmark, because all the muscles of the rectus sheath below at 15

16 this level, are at the anterior wall, and the posterior wall is only formed by fascia transversalis, - Anterior Wall: aponeuroses of all muscles (external oblique, internal oblique and transversus). - Posterior Wall: transversalis fascia and lies below it extraperitoneal fat and peritoneum. (Content: rectus abdominis muscle.) Arcuate line (linea semicircularis): Is a crescent-shaped line marking the inferior limit of the posterior layer of the rectus sheath just below the level of the iliac crest. Below it, we can find the transversalis fascia. All muscles are anterior at level of this line - The general action of the anterior abdominal muscles: a. Increase the intra-abdominal pressure when it is needed in the following processes: Vomiting, Coughing, Defecation, Labor, Micturition (urination) and Bending of the trunk forward - These muscles protect the viscera when contracted (when you are playing boxing, the muscles of the abdomen take the role of the protection when contacted. If contraction didn t take place the viscera will be affected and bleeding may occur) - They help in lifting heavy objects (people who lift heavy objects usually tie a strap on the abdomen to help the muscles doing their action, and to avoid hernia). - These muscles keep viscera in position Clinical Notes (SLIDES) - Abdominal stab wounds Lateral to rectus sheath Ant. To rectus sheath 16

17 In the midline= Linea alba - Structures in the various layers through which an abdominal stab wound depends on the anatomical location - Surgical incision - The length and direction of surgical incision through the ant. Abdominal wall to expose the underlying viscera are largely controlled by 1- position & direction of nerves 2- direction of muscle fibers 3- arrangement of the aponeurosis forming the rectus sheath - The incision should be made in the direction of the line of cleavage in the skin so that the scare is produced Meaning that surgical incision should be parallel to skin cleavage so that it won t leave a scar. doctors should also be aware of the pathway of the nerves. So they pull rectus sheath laterally to protect the nerves which pass from medial to lateral. And the direction of the muscle fibers is also important. - Incision through the rectus sheath Widely used The rectus abdominis muscle and its nerve supply are kept intact On closure the ant & post wall of the sheath are sutured separately and the rectus muscle back into position between the suture lines Common types of incisions Paramedian incision Pararectus incision Midline incision Transrectus incision Transverse incision Muscle splitting Abdominothoracic incision A note I could not place: L1 nerve passes above inguinal ligament and divides into 2 branches: iliohypogastric and ilio-inguinal (Ilioinguinal enters from deep to superficial ring supplying scrotum and it also serves as sensory innervation to lower abdomen) I ve heard record4+ used slide2 to write this sheet, Sorry if I missed anything, GOOD LUCK!! Telos is not only about your Ultimate steps, But also your first ones -MahaAbuAja100 17