ABDOMINAL ANATOMY Flashcards
simple way of dividing the anterior abdominal wall
four quadrants: right upper, right lower, left upper and left lower
more complicated way of dividing the abdominal wall
9 quadrants
two vertical mid clavicular lines
two horizontal lines (trans-pyloric at L1 or subcostal plane L3 or trans tuebcular plane L5)
Right hypochondrium, epigastric, left hypochondrium
right lumbar, umbilical, left lumbar
right iliac/inguinal, pubic/hypogastric, left iliac/inguinal
anterior abdominal wall functions
firm yet flexible boundary which keeps the abdominal viscera within the abdominal cavity, maintain their anatomical position
protect abdominal viscera from injury
assists forceful expiration by pushing abdominal viscera upwards
increases intra-abdominal pressure
what is the anterior abdominal wall formed of?
skin, superficial fascia, muscles and associated fascia and parietal peritoneum
two groups of muscles in the anterior abdominal wall
flat muscles- situated laterally on either side of the abdomen
vertical muscles- situated midline of the body
flat muscle structures + function
fibres run in differing directions and cross each other- strengthen the wall and decrease risk of herniations
each muscle forms an anteriomedial aponeurosis
what do the aponeuroses form in the midline?
linea alba
how many flat muscles?
3
what is the inguinal canal?
a canal formed between the deep inguinal ring and the superficial inguinal ring
boundaries of inguinal canal
roof- transveralis fascia, internal oblique
posterior wall, transversalis fascia
anterior wall- aponeurosis of external oblique, internal oblique
floor- inguinal ligament
inguinal canal function
women- carries round ligament of uterus, ilioinguinal nerve etc
men- spermatic cord and its contents, ilioinguinal nerve
consequence of a deficiency in the abdominal wall
inguinal hernias
explain inguinal hernias
abdomen is not strong enough
results in protrusion of abdominal cavity contents into the inguinal canal
posterior abdomen structure
formed of diaphragm and its crura
psaos major and minor form from diaphragm and insert onto iliac crest
quadratus lumborum forms sides
illiacus originates from iliac crest and becomes the iliopsoas and inserts onto the lesser trochanter of femur
what is the pelvic floor?
a muscular partition formed by muscles that separates the pelvic cavity above from the perineal region
structure of pelvic floor
right and left levator ani muscles, lying almost horizontally with the pelvis
levator ani components
pubococcygeus, puborectaluis and iliococcygeus
coccygeus muscle
associated connective tissue
function of pelvic floor
provide support for pelvic viscera e.g bladder, intestines and uterus
help maintain continence as part of the urinary and anal sphincters
peritoneum definition
a serous membrane that lines the walls of the abdominopelvic cavity and covers the abdominopelvic organs
two groupings of structures within the abdomen + definition
retroperitoneal- organs in contact with the posterior abdominal wall. Not covered with visceral peritoneum, only anterior surface covered with parietal peritoneum
intraperitoneal- further away from the wall, completely invested in peritoneum
two types of peritoneum + location
visceral- lining the organs
parietal- lining the cavity
what is the peritoneal cavity + what can it be divided into?
space between the two peritoneal membranes, filled with peritoneal fluid
subdivided into the greater sac and the lesser sac
two different types of retroperitoneal organs + definition
primarily retroperitoneal- organs developed and remain outside the parietal peritoneum
secondarily retroperitoneal organs- initially intraperitoneal suspended by mesentery. Mesentery fused with posterior abdominal wall
examples of primarily retroperitoneal structures
kidneys, oesophagus, rectum
