Anatomy - Abdomen/Oesophagus/Stomach

Question 1

what 2 types of walls are found in the abdomen?

Answer 1

musculofascial anterolateral
musculofascial posterior

Question 2

what skeletal structures do the abdominal walls attach to?

Answer 2

vertebral column
thoracic cage (inferior margin)
bony pelvis (superior margin)

Question 3

what is the roof and floor of the abdominal cavity?

Answer 3

roof - diaphragm
floor - no floor (continuous with pelvic cavity)

Question 4

what lines separate the regional descriptive abdominal layout?

Answer 4

2 midclalvicular planes (vertical)
subcostal plane (upper horizontal)
intertubercular plane (lower horizontal)

Question 5

what lines separate the quadrant descriptive abdominal layout?

Answer 5

median plane (vertical)
transumbilical plane (horizontal)

Question 6

describe the subcutaneous tissues of the abdominal wall

Answer 6

above umbilicus - single sheet of CT
below umbilicus - 2 layers of CT:
- camper’s fascia (fatty layer/superficial)
- scarpa’s fascia (membranous/deep)

Question 7

describe the features of the rectus abdominus/pyramidalis muscle pairing

Answer 7

rectus abdominus - paired/separated by linea alba, attached to pubic symphysis/crest, xiphoid process and ribs 5-7, broad and thin superiorly and narrow and thick inferiorly, transverse tendinous intersections
both contained in rectus sheath (formed from aponeuroses of thin, flat abdominal muscles

Question 8

describe the features of the 3 flat muscles of the anterolateral abdominal wall

Answer 8

external oblique - superficial, fibres run in inferomedial direction
internal oblique - intermediate, fibres run in superomedial direction
transverse abdominis - deep, fibres run in transverse direction
function - stabilises vertebral column, moves abdominal trunk, tenses abdominal wall

Question 9

what are the features of the posterior abdominal wall?

Answer 9

skeletal - lumbar vertebrae, pelvic girdle, ribs 11/12
musculofascial - thoracolumbar fascia, psoas fascia

Question 10

name the muscles contributing to the posterior abdominal wall

Answer 10

quadratus lumborium (thick muscular sheet)
psoas major
psoas minor (not always present)
iliacus (combines with psoas major forming iliopsoas)

Question 11

explain the basics of peritoneum

Answer 11

continuous serous membrane lining abdominopelvic cavity
parietal - lines abdominal walls
visceral - covers viscera
peritoneal cavity - potential space/peritoneal fluid

Question 12

explain the difference between intraperitoneal and retroperitoneal structures

Answer 12

intraperitoneal - suspended within the cavity (stomach/spleen)
retroperitoneal - outside cavity posteriorly, only anterior surface covered with parietal peritoneum (kidneys)

Question 13

explain the subdivisions of the peritoneal cavity

Answer 13

greater sac - entered once parietal peritoneum is penetrated
lesser sac (omental bursa) - posterior to stomach/liver, continuous with greater sac through omental (epiploic) foramen

Question 14

what are omenta?

Answer 14

peritoneal folds connecting abdominal organs

Question 15

what is the greater omentum?

Answer 15

peritoneal fold draping over intestines
from greater curvature of stomach/duodenum to transverse colon

Question 16

what is the lesser omentum?

Answer 16

peritoneal fold from lesser curvature of stomach/duodemum to inferior liver

Question 17

what ligaments are connected to the lesser omentum?

Answer 17

hepatogastric and hepatoduodenal

Question 18

what are mesenteries?

Answer 18

double layers of peritoneum attaching viscera to posterior abdominal wall, allows neurovascular structures to reach viscera from body wall

Question 19

explain briefly the colic compartments

Answer 19

the transverse mesocolon divides the abdomen into supracolic and infracolic compartments
paracolic gutters allow communication between them

Question 20

name the components of the supracolic compartment

Answer 20

stomach
liver
spleen

Question 21

name the components of the infracolic compartment

Answer 21

small intestine
ascending/descending colon
(divided L/R by mesentery of small intestine)

Question 22

explain the localisation of pain in the peritoneum

Answer 22

parietal - well localised due to same spinal nerve as region of abdominal wall
visceral - general visceral afferents of the ANS causing poorly localised pain

Question 23

explain the anatomy of the abdominal oesophagus

Answer 23

short/distal oesophagus
passes through diaphragm at T10 (oesophageal hiatus)
enters stomach at cardial orifice

Question 24

explain the blood supply to the stomach

Answer 24

lesser curvature - L/R gastric arteries (L - coeliac trunk, R - hepatic artery)
greater curvature - L/R gastro-omental arteries (L - splenic artery, R - gastroduodenal artery)
fundus - short gastric arteries (splenic artery)

Question 25

explain the venous drainage of the stomach

Answer 25

L/R gastric veins
L/R gastro-omental veins
short gastric veins
(pre-pyloric vein ascends over pylorus, used for identification)