Anterior Abdominal Wall PDF

Anterior Abdominal Wall DPM PROGRAM 1. Describe the location of the abdominal cavity. 2. Identify palpable landmarks of the abdomen utilized for physical exam or clinical procedures. 3. Describe the regional and quadrant reference systems of the abdomen and the position of abdominal viscera relativ...

Anterior Abdominal Wall DPM PROGRAM 1. Describe the location of the abdominal cavity. 2. Identify palpable landmarks of the abdomen utilized for physical exam or clinical procedures. 3. Describe the regional and quadrant reference systems of the abdomen and the position of abdominal viscera relative to these systems. 4. Describe the organization and function of the abdominal wall, including fascial and muscle layers in terms of attachments, actions, innervation, and blood supply. 5. Describe the layers of the abdominal wall. 6. Describe the conjoint tendon. 7. Describe the nerve supply of the abdominal wall. 8. Describe the dermatomes of the abdominal wall. 9. Describe the arterial supply and venous drainage of the abdominal wall. 10. Describe the lymphatic drainage of the abdominal wall. 1 SMU - Internal Data Describe the location of the abdominal cavity. • Part of the trunk inferior to the thorax • A wall surrounds a large cavity known as the abdominal cavity • Bounded superiorly by the diaphragm • Inferiorly by the pelvic inlet • Arbitrarily separates the abdominal cavity and pelvic cavity 2 SMU - Internal Data Identify palpable landmarks of the abdomen utilized for physical exam or clinical procedures. -will be discussed throughout lecture Landmarks used to delineate the extent of the abdomen on the surface of the body: Costal margin: -separates abdominal wall from thoracic wall Pubic tubercle & anterior superior iliac spine -line between these marks the inguinal ligament(separates anterior abdominal wall from lower limb) Iliac crest -separates posterolateral abdominal wall from the gluteal region 3 SMU - Internal Data Topographical divisions of the abdomen are used to describe the location of abdominal organs and the pain associated with abdominal problems. 2 schemes most often used: 1) Four-quadrant pattern 2) Nine-region pattern 4 SMU - Internal Data Describe the quadrant reference system of the abdomen and the position of abdominal viscera relative to these systems. Median plane Four quadrants: • Right upper • Left upper • Right lower • Left lower Horizontal transumbilical plane Created by: 1) Horizontal transumbilical plane -passes through umbilicus -intervertebral disc between LIII and LIV 2) Median plane -xiphoid process to pubic symphysis 5 SMU - Internal Data Upper right quadrant Lower right quadrant SMU - Internal Data **note not all structures for each quadrant listed will discuss in following lectures Upper left quadrant Lower left quadrant 6 Describe the regional reference systems of the abdomen and the position of abdominal viscera relative to these systems. Nine-region pattern is based on 2 horizontal and 2 vertical planes. 2 vertical: • Midclavicular planes • From midpoint of clavicle to midpoint of inguinal ligament 2 horizontal (transverse): • Subcostal plane • Immediately inferior to costal margins • Lower border of costal cartilage rib 10 • Through vertebrae LIII • Note: sometimes the transpyloric plane is used • Passes through the pylorus of the stomach • Midway between jugular notch and pubic symphysis at the level of LVI/LV2 • Intertubercular plane • Connects tubercles of iliac crest • Passes through upper part of vertebrae L5 7 SMU - Internal Data Describe the organization and function of the abdominal wall, including fascial and muscle layers in terms of attachments, actions, innervation, and blood supply. 8 SMU - Internal Data Describe the layers of the abdominal wall. Anterolateral wall (below the umbilicus) Superficial Skin (epidermis/dermis) Superficial fascia -Camper’s (superficial fatty fascia) -Scarpa’s (membranous fascia) This layers serves to reinforce this portion of the wall that lacks bony support Abdominal Muscles and their deep fascia -Rectus Abdominis m. -External oblique m. -Internal oblique m. -Transversus abdominis m. Transversalis fascia -covers the inner surface of the transversus abdominis m. Extraperitoneal fascia Deep Parietal Peritoneum -serous membrane lining the abdominopelvic cavity 9 SMU - Internal Data 10 SMU - Internal Data Camper’s Fascia (superficial fatty layer of superficial fascia) Continuous over the inguinal ligament with the superficial fascia of the thigh. In men: -continues over the penis -continues into scrotum (forms dartos fascia) In women: -superficial layer retains some fat -component of labia majora 11 SMU - Internal Data Scarpa’s Fascia (deeper membranous layer of superficial fascia) Thin and membranous contains no fat. • Inferiorly, continues into the thigh, just below inguinal ligament it fuses with deep fascia of the thigh (fascia lata) • Midline, attaches to linea alba and pubic symphysis • Firmly attaches to the ischiopubic rami and perineal membrane, referred to as the superficial perineal fascia (Colles’ fascia) • In men: • Contributes to dartos fascia • In women: • Continues into labia majora 12 SMU - Internal Data Anterolateral abdominal wall muscles The muscles of the anterolateral abdominal wall include the: • Rectus abdominis -investing fascia is called rectus sheath -fibers are divided by ¾ bands called tendinous intersections • External abdominal oblique • Internal abdominal oblique • Transversus abdominis -all have insertions in the inguinal region Each abdominal muscle has its own investing fascia. Primary Functions of these Muscles: -Movement & maintenance of posture -Support, protection, compression of abdominal viscera -Regulation of intra-abdominal pressure assists in expulsion of abdominal organ contents in urination (micturition), defecation, vomiting & childbirth by increasing intra-abdominal pressure 13 SMU - Internal Data Rectus Abdominis • Extends length of anterior abdominal wall • Origin: pubic crest • Insertion: Xiphoid process/Costal margin • Innervation: Lower 6 intercostal, subcostal, iliohypogastric & ilioinguinal nerves • Paired and separated by Linea alba (white line) • Intersected by 3-4 transverse fibrous bands or tendinous intersections • Rectus Sheath• is the aponeuroses of the three anterolateral abdominal muscles, and encloses the rectus abdominis m. • It is complete anteriorly, but is incomplete in posteroinferior portion, leaving only transversalis fascia. SMU - Internal Data Linea alba Rectus abdominis Anterior rectus sheath Tendinous intersection Anterior abdominal wall 14 Posterior rectus sheath Arcuate line (where posterior rectus sheath ends) Transversalis fascia Anterior abdominal wall/deep dissection SMU - Internal Data 15 External abdominal, internal abdominal, transversus abdominis oblique External abdominal oblique Origin: lower 8 ribs Internal abdominal oblique Origin: lateral 2/3 of the inguinal ligament, iliac crest, and thoracolumbar fascia Transversus abdominis Origin: Lower ribs, lateral 1/3 of the inguinal ligament, iliac crest, and thoracolumbar fascia Insertion: rectus sheath (linea alba) Innervation: Lower 6 intercostal, subcostal, iliohypogastric & ilioinguinal nerves External abdominal oblique Transverse abdominis oblique Internal abdominal oblique Anterior abdominal wall 16 SMU - Internal Data Muscles of the anterolateral abdominal wall: origin, insertion, action, innervation Muscle Origin Insertion Rectus abdominis Pubic crest Xiphoid process and costal margin External Oblique Lower 8 ribs Rectus sheath (linea alba) Internal Oblique Lateral 2/3 of the inguinal ligament, iliac crest and thoracolumbar fascia Rectus sheath (linea alba) Transversus Abdominis Lower ribs, Lateral 1/3 of the inguinal ligament, iliac crest and thoracolumbar fascia Rectus sheath (linea alba) Actions Innervation These muscles function in trunk movement, breathing, defecation, and support. Lower 6 intercostal, subcostal, iliohypogastric & ilioingional nerves 17 SMU - Internal Data Describe the conjoint tendon. Combined inferior aspect of the aponeuroses of: • Internal oblique • Transverse abdominis Inserts on the pectineal line Muscle fibers form an arch over the • Spermatic cord (male) • Round ligament (female) 18 SMU - Internal Data Extraperitoneal Fascia and Peritoneum Extraperitoneal fascia • Deep to transversalis fascia • Contains varying amounts of adipose tissue • Abundant on posterior abdominal wall (especially in kidneys) Peritoneum • Deep to extraperitoneal fascia • Thin serous membrane lines wall of abdominal cavity (parietal and visceral layers) • Continuous lining of the abdominal walls by parietal peritoneum forms a sac • Sac called: peritoneal cavity • Sac has 2 openings in women where uterine tubes provide a passage to the outside • In men, sac is closed 19 SMU - Internal Data Describe the nerve supply of the abdominal wall. Skin, muscles, and parietal peritoneum of the anterolateral abdominal wall are supplied by: • Thoracoabdominal (T7-T11, T12) • Subcostal (T12) • Iliohypogastric (L1) • Ilioinguinal (L1) Anterior (ventral rami) travel: • Towards the midline • Between internal abdominal oblique and transversus abdominis muscle • Supply the skin 20 SMU - Internal Data Describe the dermatomes of the abdominal wall. T7 to T12 and L1 supply branches to the anterolateral abdominal wall muscles and underlying parietal peritoneum. • T5/T6: skin over xiphoid process • T7-T9: skin from xiphoid process to just above umbilicus • T10: skin around the umbilicus • T12: skin over ASIS and hip • Iliohypogastric (L1): skin of hypogastric region and over pubic crest • Ilioinguinal (L1): skin of scrotum or labium majus, mons pubis, adjacent medial aspect of thigh 21 SMU - Internal Data Describe the arterial supply and venous drainage of the abdominal wall. Superficially: • Musculophrenic artery (branch of internal thoracic) • Superior part of the abdominal wall • Superficial epigastric (branch of internal thoracic)/superficial circumflex iliac artery (branch of femoral artery) • Inferior part of abdominal wall Deeper: • Superficial epigastric (branch of internal thoracic) • Superior third of wall • Enters rectus sheath posteriorly • Will anastomose with inferior epigastric vessels • Inferior epigastric/deep circumflex iliac (both branches of external iliac artery) • Run in transversalis fascia to enter rectus sheath • Anastomose with superior epigastric vessels. Note: Superficial epigastric veins (in the superficial fascia) usually drain into the great saphenous vein. They may become engorged (caput medusae) in cases of portal hypertension. They anastomose with paraumbilical veins that empty into the hepatic portal vein. SMU - Internal Data 22 Describe the lymphatic drainage of the abdominal wall. Lymphatic drainage of the anterolateral abdominal wall follows as: Superficial Drainage: • Superficial lymphatics above the umbilicus pass in a superior direction to: Axillary nodes Parasternal nodes Axillary nodes (above umbilicus) • Superficial drainage below the umbilicus pass in an inferior direction to: Superficial inguinal nodes Deep Drainage: • Follows deep arteries back to: • Parasternal nodes • Along the internal thoracic artery • Lumbar nodes • Along abdominal aorta • External iliac nodes • Along external iliac artery Lumbar nodes External iliac nodes Superficial inguinal nodes (below umbilicus) 23 SMU - Internal Data