GA Flashcards
what is the anterior portion of the abdominal wall made up of?
aponeuroses and muscles
layers of the anterior and antero-lateral abdominal walls:
skin, superficial fascia, deep fascia/epimysium, muscles, fascia transversalis, extraperitoneal fat, peritoneum
roles of the abdominal wall:
- protects viscera of the abdomen
- flexes and laterally rotates the spine
- depresses the ribs
- increases intra-abdominal P by contracting muscles
- assists in forced expiration, coughing, sneezing, peeing, pooping
tension lines
direction of collagen fibers on the skin which result in a practically invisible scar if an incision is made in the direction in which they run
4 abdomen shapes and what could cause it:
shapes: flat, rounded, scaphoid, protrubent
causes: feces, fetus, food, flatus, fluid, fat
superficial fascia
divided into two layers separated by the neurovascular bundle: Camper’s fatty layer (superficial fatty layer) and Scarpa’s membranous layer (superficial vessels) which becomes continuous with the fascia of the back and thorax
deep fascia/epimysium
thin connective tissue sheath that covers individual abdominal muscles anteriorly and posteriorly
muscles of the abdomen
3 lateral: external oblique (most superficial), internal oblique (perpendicular to external) and transversus abdominis
2 medial: rectus abdominis and pyramidalis (strengthens linea alba but may not be present or paired in some people)
fascia transversalis
thin layer of fascia lining transversus abdominis muscle continuous with another layer lining the diaphragm and iliacus muscle
rectus sheath
formed from aponeuroses of the three anter-lateral muscles to encapsulate the rectus abdominis muscles
*internal oblique aponeurosis will split and half follows the external oblique muscle anteriorly and the other half follows the tranversus aponeurosis posteriorly (wraps n the rectus muscle)
extraperitoneal fat
thin layer of CT with fat that lies between fascia transversalis and peritoneum
peritoneum
large serous membrane containing a single layer of epithelial cells lying on a layer of loose CT serving to minimize friction, resist infection and store fat
*parietal when lining the abdominal wall and then reflexed to become visceral when surrounding organs–> peritoneal fluid exists in the peritoneal cavity formed between the parietal and visceral peritoneum
foramen epiplocium/of Winslow
the way by which the greater and lesser sac communicate with one another
intraperitoneal vs. retroperitoneal organs
intraperitoneal: surrounded by peritoneal cavity (ex: liver, spleen)
retroperitoneal: only one part is dressed (ex: kidneys)
greater omentum vs. lesser omentum
greater: hangs from transverse colon and has 4 layers of peritoneum (2 anterior and 2 posterior)–> usually perforated (from the dorsal mesentery)
lesser: from the inferior part of the liver to other organs and consists of the hepatogastric ligament (liver to stomach) and the hepatoduodenal (porta hepatis to duodenum containing portal triad) ligament (from the ventral mesentery)
what connects the liver to the diaphragm?
visceral ligaments made of double layers of peritoneum and the lesser omentum:
1 falciform
2 coronary
2 triangular
what makes up the portal triad?
bile duct, hepatic vein and hepatic artery
mesentery
folds of peritoneum connecting intestines to posterior abdominal wall and contains vessels and nerves
(if organ presents it, it will be intraperitoneal)
9 regions of the abdomen
left to right:
R hypochondriac, epigastric, L hypochondriac
R lumbar, umbilical, L lumbar
R iliac, hypogastrin, L iliac
what exists in each quadrant?
upper right: liver, gallbladder, stomach antrum, duodenum, right kidney, right adrenal (suprarenal), pancreas (head), colon (hepatic flexure), IVC
upper left: abdominal esophagus, stomach fundus, spleen, left kidney, left adrenal, abdominal aorta, pancreas (body, tail), part of jejunum, colon (spenic flexure)
lower right: ileum, ascending colon, cecum, appendix, right ureter
lower left: part of jejunum, part of ileum, descending colon, sigmoid colon, left ureter
where does the esophagus pierce the diaphragm and then where does it enter the stomach?
pierces diaphragm at: esophageal hiatus
enters stomach at: cardia
what determines sites of organ formation?
interactions between the endoderm and visceral mesoderm
divisions of the primitive gut tube
foregut (head to liver), midgut (liver to right 2/3 and left 1/3 of transverse colon) and hindgut (left 1/3 of transverse colon to cloacal membrane)
development of the esophagus and clinical significance
development: develops from the foregut then at 4 weeks, lung buds evaginate and the tracheoesophageal septum separates the foregut into the primordium of the respiratory tract from the esophagus
clinical significance: defects leads to esophageal atresia or tracheoesophageal fistula preventing normal swallowing leading to excess fluid in the amniotic sac (polyhydramnios)
development and rotation of the stomach
5th week- stomach rotates 90 degrees to the right around the craniocaudal axis–> dorsal aspect grows more rapidly forming greater curvature and ventral portion becomes lesser curvature
further growth- stomach rotates around its anteroposterior axis so caudal/pyloric end moves to right and cephalic/cardiac end moves to left ballooning out and forming the omental bursa (space behind stomach)
development of duodenum and clinical significance
development: retroperitoneal and forms a C-shaped loop that rotates right whose lumen is obliterated by proliferation of cells from walls but is soon recanalized
clinical significance: duodenal stenosis or atresia if canalization is incomplete (leads to polyhydramnios)
what causes the mesoduodenum to fuse with the peritoneum?
the duodenum and head of the pancreas pressing against the dorsal body wall