The Abdomen Surface Anatomy, Vessels, Muscles, and Peritoneum
Surface Anatomy Anterior abdominal wall extends from costal margin to inferior boundaries: Iliac crest Anterior superior iliac spine Inguinal ligament Pubic crest Superior boundary Diaphragm Central landmark Umbilicus Linea alba (white line) Tendinous line Extends from xiphoid process to pubic symphysis
Abdominal Quadrants 9 regions 4 quadrants Draw line through navel Right upper quadrant Left upper quadrant Left lower quadrant Right lower quadrant
Muscles Function: Help contain abdominal organs Move trunk Forced breathing Increase intraabdominal pressure Abdominal wall Anterior (4) Innervated by intercostal nerves Continuous with layers of intercostal muscles Fibers of layers run in different directions for strength Ends in aponeurosis which contains rectus abdominis muscle Posterior (3)
Anterior Abdominal Wall Muscles Rectus Abdominis Origin Pubic crest, symphysis Insertion Xiphoid process, costal cartilages of ribs 5-7 Function Flex, rotate trunk, fix and depress ribs, stabilize pelvis, compress abdomen
Anterior Abdominal Wall External oblique ( hands-in-pocket ) Origin Lower 8 ribs Insertion Aponeurosis to linea alba, pubic and iliac crest Function Flex trunk, compress abdominal wall (together), rotate trunk (separate sides) Internal oblique Origin Lumbar fascia, iliac crest, inguinal ligament Insertion Linea alba, pubic crest, last 3-4 ribs, costal margin Function Same for external obliques
Transversus abdominis Origin Inguinal ligament, lumbar fascia, cartilage of last 6 ribs, iliac crest Insertion Linea alba, pubic crest Function Compress abdominal contents
Levels of Rectus Abdominis Muscle Sheath Structures
ANTERIOR ABDOMINAL WALL Cord of connective tissue LINEA ALBA Extend sternum (xyphoid process) symphysis, pubic bones Aponeurotic parts of oblique muscles attache to the linea alba at the midline One of the surgical approaches to the peritoneal cavity (midline incision)
Weak Places of the Anterior Abdominal Wall
Layer Structure of the Anterior Abdominal Wall
Abdominal Incisions Must locate nearest to the organ. Must have sufficient length for surgeon activities. Must be atraumatic.
Skin Incisions of the Ventral Abdominal Wall
Male Inguinal Canal
Female Inguinal Canal
Superficial Inguinal Ring
Internal Inguinal Ring
Anterior Abdominal Wall (lower internal view)
Posterior Abdominal Wall Iliopsoas Psoas major Origin Lumbar vertebrae, T 12 Insertion Lesser trochanter of femur via iliopsoas tendon Function Thigh flexion, trunk flexion, lateral flexion Innervation Ventral rami L1-L3 Iliacus Origin Iliac fossa, ala of sacrum Insertion Lesser trochanter of femur via iliopsoas tendon Function Thigh flexion, trunk flexion Innervation Femoral nerve (L2 and L3) Psoas minor variable (40-60% do not have)
Posterior Abdominal Wall Quadratus lumborum Origin Iliac crest and lumbar fascia Insertion Transverse process of upper lumbar vertebrae, lower margin of rib 12 Function Flex vertebral column, maintains upright posture, assists in inspiration Innervation: T12 and upper lumbar spinal nerves (ventral rami)
Abdominopelvic Cavity Ventral body cavity Thoracic Abdominopelvic Abdominopelvic Abdominal Liver Stomach Kidneys Pelvic cavity Bladder Some reproductive organs Rectum
Abdominal cavity The space bounded by: Anterolateral abdominal wall Posterior abdominal wall Diaphragm Pelvic walls and pelvic floor. Subdivided into: True abdominal cavity (from diaphragm to linea terminalis) Pelvic cavity (below linea terminalis).
Peritoneum and peritoneal compartment Peritoneum is a continuous serous membrane, composed of two layers: Parietal peritoneum, lines abdominal and pelvic wall Visceral peritoneum, lines abdominal and pelvic organs. Peritoneal compartment is part of the abdominal cavity enclosed within the parietal peritoneum. Contains organs covered with peritoneum and peritoneal structures. Outside the parietal peritoneum is the extraperitoneal compartment of the abdominal cavity.
Peritoneal cavity Peritoneal cavity (PC) - the space between the two peritoneal layers, is a potential space, into which the organs are tightly packed against each other. PC contains thin layer of fluid, which lubricates the peritoneal surfaces and allows movement of the organs without friction. PC is closed in males, but communicates with the external environment in females through the uterine tubes, uterus and vagina. Peritoneum, peritoneal cavity and all the organs are situated in the abdominal cavity.
Development of the peritoneum
Relationship between the organs and peritoneum Due to intraembryonal processes the organs have different relationship with the peritoneum. 1. Intraperitoneal organs are entirely covered with peritoneum. They are connected to the abdominal wall with ligaments or meso, which ensures greater mobility. 2. Extraperitoneal organs are partially or entirely devoid of peritoneum. They are slightly movable or immovable. According to their position these are: а) retroperitoneal on the posterior abdominal wall b) subperitoneal in the lesser pelvis c) preperitoneal at the anterior abdominal wall.
Vertical layout of the peritoneum
Horizontal layout of the peritoneum
Passage of the parietal into visceral peritoneum
Peritoneal structures 1. Mesentery double peritoneal layer, representing elongation of the visceral peritoneum. М. connects the corresponding organ with the abdominal wall (e.g., mesentery of the small intestine). М. contains connective tissue in which are embedded blood vessels, nerves and lymph nodes. М. ensures mobility of the organs.
2. Omentum double layered structure of visceral peritoneal, extending from the stomach to neighbouring organs. Lesser omentum (оmentum minus) connects the lesser curvature of the stomach and intitial portion of pars superior duodeni with liver. Greater omentum (оmentum majus) descends from the greater curvature of the stomach and intitial portion of pars superior duodeni, covers the intestines, and then ascends back to attache to the transverse colon. Contains great amount of fat tissue.
3. Peritoneal ligaments double layered structures of visceral peritoneum, between neighbouring organs or between organ and abdominal wall (e.g., lig. falciforme, lig. gastrophrenicum, lig. gastrolienale, lig. gastrocolicum). 4. Peritoneal folds (plicae) formed over underlying structures (e.g., plica iliocecalis superior, plica umbilicalis mediana). 5. Peritoneal recessuses spaces in the peritoneal cavity заградени between peritoneal structures and abdominal organs or abdominal wall (e.g., bursa omentalis, recessus subphrenicus, fossa retrocecalis).
Divisions of the peritoneal cavity By mesocolon transversum the peritoneal compartment divites into: 1. Supracolic compartment between diaphragm and mesocolon transversum with its mesentery. 2. Infracolic compartment - between mesocolon transversum and linea terminalis. 3. Pelvic compartment - below linea terminalis in the pelvi cavity.
Supracolic compartment Organs: 1. Esophagus, pars abdominalis - intraperitoneal 2. Stomach - intraperitoneal 3. Liver - intraperitoneal 4. Gall bladder - intraperitoneal 5. Spleen - intraperitoneal
Supracolic compartment. Projections of organs
Supracolic compartment Peritoneal structures: 1. Lig. falciforme hepatis lig. teres hepatis 2. Lig. coronarium hepatis (dextum et sinistrum) area nuda 3. Lig. triangulare (dextum et sinistrum)
Supracolic compartment 4. Omentum minus lig. hepatogastricum lig. hepatoduodenale 5. Omentum majus lig. gastrocolicum lig. gastrolienale lig. gastrophrenicum 6. Lig. phrenicolienale
Supracolic compartment Peritoneal spaces: 1. Recessus subphrenicus dexter - bursa hepatica 2. Recessus subphrenicus sinister - bursa pregastrica 3. Perilienal space 4. Recessus subhepaticus а) anterior part b) posterior part - recessus hepatorenalis 5. Bursa omentalis
Supracolic compartment Bursa omentalis. Opened thru lig. hepatogastricum Bursa omentalis. Opened thru lig. gastrocolicum
Infracolic compartment Organs: 1. Small intestine duodenum (pars superior, descendens, horizontalis, ascendens) - retroperitoneal, pars superior intraperitoneal Jejunum and ileum - intraperitoneal 2. Large intestine cecum - intraperitoneal appendix vermiformis - intraperitoneal colon (ascendens, transversum, descendens, sigmoideum) - intraperitoneal /mesoperitoneal rectum most extraperitoneal
Organs and projections
Peritoneal structures 1. Omentum majus - pars libera 2. Mesenterium 3. Mesocolon transversum 4. Mesocolon sigmoideum 5. Mesoappendix
Peritoneal structures 1. Plicae duodenalis superior/inferior - recessus duodenalis superior/inferior 2. Plicae ileocecalis superior/inferior - recessus ileocecalis superior/inferior
Peritoneal spaces 1. Canalis lateralis dexter 2. Sinus mesentericus dexter 3. Sinus mesentericus sinister 4. Canalis lateralis sinister 5. Recessus intersigmoideus 6. Recessus retrocecalis
Appendix vermiformis
Supracolic compartment. Blood supply Truncus celiacus 1. A. gastrica sisnistra - r. esophageus 2. A. hepatica communis - a. hepatica propria - a. hepatica dextra/sinistra - a. gastroduodenalis - a. gastroepiploica dextra - aa. pancreaticoduodenales superiores (anterior/posterior) - a. gastrica dextra 3. A. lienalis - aa. gastricae breves - a. gastroepiploica sinistra
Supracolic compartment. Blood supply
Arteriogram of truncus celiacus
Infracolic compartment. Blood supply A. mesenterica superior 1. A. pancreaticoduodenalis inferior 2. Aa. intestinales (15-18) 3. A. iliocolica 4. A. colica dextra 5. A. colica media
Infracolic compartment. Blood supply A. mesenterica inferior 1. A. colica sinistra 2. Aa. sigmoideae (3-4) 3. A. rectalis superior