Abdomen, Pelvis, Perineum Part 1 DR Flashcards
what are the borders of the abdomen
superior border - diaphragm (separates thorax and abdomen)
inferior border - plane of superior pelvic aperture/pelvic inlet
how can the abdomen be divided
draw the areas and the lines which divide them
can be divided into 4 quadrants or 9 regions
what is contained within each of the 9 regions of the abdomen
what is contained within each of the 4 quadrants of the abdomen
what is the peritoneal cavity
the potential space between the parietal peritoneum covered abdominal wall and the abdominal organs covered with visceral peritoneum
normally contains a thin film lubricant - peritoneal fluid which allows free movement of abdominal viscera
what are the layers of anterolateral abdominal wall
what is investing fascia
superior, intermediate and deep investing fascia covers surface of the external oblique, internal oblique and transversus abdominis respectively
what separates the parietal peritoneum and transversalis fascia
extra-peritoneal fat
what are the muscles of the anterolateral abdominal wall
5 bi-laterally paired muscles
2 vertical muscles - rectus abdominis + pyramidalis (present in 80% of people)
3 flat muscles - external oblique, internal oblique, transversus abdominis
what forms the linea alba
the interlacing of the aponeuroses of the external oblique, internal oblique and rectus abdominis from one side to the other and between external and internal oblique, internal oblique and transversus abdominis
what forms the rectus sheath
aponeuroses of the external oblique, internal oblique, transversus abdominis
anterior sheath - external oblique and internal oblique
posterior sheath - internal oblique and transversus abdominis
the posterior sheath ends at the arcuate line - transversus abdominis aponeurosis joins the anterior rectus sheath
therefore below the arcuate line posterior rectus abdominis lies directly on the transversalis fascia
describe the fibre orientation of the muscles of the anterolateral abdominal wall
what is the importance of this
external oblique - inferomedially
internal oblique - superomedially
transversus abdominis - transverse
similar to intercostal muscles, fibre orientation helps provides strength but as there are no ribs/bones the fibres are even more important
fibres of internal oblique are perpendicular to external oblique fibres
where does the anterolateral muscles become apo-neurotic
mid-clavicular lines
what are the points of attachment of the internal oblique
what are its functions
internal oblique:
origin - thoracolumbar fascia, inguinal ligament, iliac crest
insertion - ribs 10-12
(note: the actual muscles fibres are mainly lateral, and the aponeurosis is more anterior)
what are the points of attachment of the transversus abdominis
what are its functions
transversus abdominis:
origin - thoracolumbar fascia, costal cartilages 7-12, inguinal ligament, iliac crest
insertion - conjoint tendon, xiphoid process, linea alba, pubic crest
compresses and supports abdominal viscera
what are the points of attachment of the external oblique
what are its functions
external oblique:
origin - ribs 5-12
insertion - linea alba, pubic tubercle, anterior half of iliac crest
what is the reason for the fibre orientation of the transversus abdominis
what lies between the internal oblique and transversus abdominis
what is this similar to
what is the rectus abdominis
describe the shape and width of the rectus sheath superiorly to inferiorly
what is visible in people with a “six pack”
what are the points of attachment of the rectus sheath
what is the pyramidalis
what are the points of attachment of the pyramidalis
what is the arcuate line
what makes up the anterior and posterior rectus sheath
how does the rectus sheath change superiorly to inferiorly
what does the linea alba separate
what is its shape
what is its function
how is the linea alba relevant in fetal development
what are the main arteries which supply the abdominal wall
what are the functions of the anterolateral abdominal wall muscles
what are the functions of the anterolateral abdominal wall muscles
how are the anterolateral abdominal wall muscles involved in breathing
what is the significance of the dermatome distribution of the anterolateral abdominal wall
describe the nerve innervation of the abdomen (skin and muscles)
what are the arteries which supply the superior abdominal wall
(deep and superficial)
what are the arteries which supply the inferior abdominal wall
(deep and superficial)
what are the arteries which supply the lateral abdominal wall
describe the venous drainage of the abdominal wall
describe the venous drainage of the anterolateral abdominal wall
what are the peritoneal folds of the abdomen
where are they
what do they cover
what are the peritoneal fossae of the abdomen
where are they
what do they cover
can be divided into 4 quadrants or 9 regions
