aponeurosis = a tendon that’s in the form of a sheet tendon = pees cavity = holte
bifurcation = splitsing branches = taken spleen = milt intestine = darm
vessel = vat bile = gal colon = dikke darm suprarenal glands = bijnieren
Abdomen
Posterior part of abdominal wall:
Erector spinae muscles
arise from sacrum and a part from iliac crest
inserted on thoracic vertebrae and on backs of the ribs
enclosed on the front and back by the thoracolumbar fascia (=tendinous tissue)
layer on the back: arises from the spinous processes
layer on the front: arises from the transverse processes
the 2 layers of thoracolumbar fascia: fuse into thick layer along the border of erector spinae
Quadratus lumborum
lies in front of erector spinae muscles and their investing fascia
arises from 12th rib and the transverse processes of the upper 3 lumbar vertebrae
inserted on the most medial part of iliac crest and transverse process of L5
assists in producing lateral flexion
Psoas major
lies medial to quadratus lumborum
arises from transverse processes, vertebral bodies and intervertebral disks from T12 to L5
runs down across the ala of sacrum, across the sacroiliac joint and along the pelvic brim
function: flexion of hip joint
Iliacus muscle
fills the iliac fossa
arises from wide area on the wing of the ilium
down medial fibers of iliacus and lateral fibers of psoas major join forming a single muscle belly
iliopsoas: runs beneath the inguinal ligament and passes backwards to insert on lesser trochanter
of the femur
iliacus & psoas muscles are covered by the iliopsoas fascia is covered in turn by the membrane
which lines the abdominal cavity = the peritoneum
function: flexion of the hip joint
Diaphragm = highest part of abdominal wall all around
makes dome-shaped partition separating the abdominal cavity below from the thoracic
cavity above
At the bottom, the middle part of the posterior abdominal wall formed by the vertebral bodies
becomes continuous with the wall of the pelvic cavity at the sacral promontory.
Psoas muscle: stands away on each side from the vertebral bodies like a pillar
,aponeurosis = a tendon that’s in the form of a sheet tendon = pees cavity = holte
bifurcation = splitsing branches = taken spleen = milt intestine = darm
vessel = vat bile = gal colon = dikke darm suprarenal glands = bijnieren
Iliacus muscles with their investing fascia: form a continuation of the posterior abdominal wall
that slopes downward forward& inward ending at the inguinal ligament
Lowest part of the abdominal wall = the inguinal ligament
Lateral and anterior part of abdominal wall:
fill in the huge gap that’s created by the costal margin above, the edge of the thoracolumbar
fascia behind, the iliac crest, the inguinal ligament and the pubic crest below
Rectus abdominis
runs vertically next to the midline from the lower anterior ribs to the pubis
very long muscle
wide at the top& tapering to a more narrow attachment at the bottom
arises from the 5th, 6th and 7th costal cartilages
inserted on the pubic crest
divided on the front by bands of tendon tendinous intersections (3 or 4) they go about
halfway through the muscle
function: flexion of lumbar spine (in opposition to the erector spinae muscles)
important static effect: keeping the lumbar spine straight at times when the force of gravity
tends to extend it
enclosed on the front and back by tendinous envelope that’s formed by aponeuroses of the 3
flat muscles 2 layers of rectus sheath: 1. posterior rectus sheath; ends about ¾ of the way
down the muscle (the lower border = arcuate line), 2. anterior rectus sheath; extends from
the costal margin to the pubis + is firmly attached to the tendinous intersections => both
layers insert into dense mid-line band of tendinous tissue = linea alba; it extends from
xiphoid process to the pubis
3 large flat muscles: (flat may not be the best word bc in the vertical plane they’re curved)
1. Transversus abdominis (= innermost of the 3)
fibers all run in the same transverse direction (expect the lowest ones which run obliquely
downwards)
at the top: its fibers arise from the inner aspect of the costal margin from 6 th rib to 12th rib
between 12th rib and ilium: arises from the edge of thoracolumbar fascia
below: arises from the inner aspect of iliac crest
the lowest fibers arise from a thickening of iliopsoas fascia
has a short free lower border
muscle fibers end in transversus aponeurosis (= broad sheet of tendon); fuses with the
overlying internal oblique muscle to form one aponeurotic layer
2. Internal oblique
arises from thoracolumbar fascia& from iliac crest
lowest fibers: arise, like those of transversus, from a thickening of the iliopsoas fascia
has a short free lower border
fans out => so that its highest and lowest fibers run in different directions
, aponeurosis = a tendon that’s in the form of a sheet tendon = pees cavity = holte
bifurcation = splitsing branches = taken spleen = milt intestine = darm
vessel = vat bile = gal colon = dikke darm suprarenal glands = bijnieren
back: the fibers run steeply upwards then they run less steeply then they’re
transverse& then, towards the inguinal region, they run downward
highest fibers: insert on lowest 3 ribs
remaining fibers: end in internal oblique aponeurosis; fuses on the underside with the
transversus aponeurosis + joined on its outer aspect by external oblique aponeurosis
the combined aponeurotic layer divides at the edge of the rectus into 2 layers, one passing
behind and one passing in front of the rectus
below: the combined layer doesn’t divide but passes entirely in front of the muscle
3. External oblique (= outermost of the 3)
fibers spiral downwards and forwards at the side downwards and medially in front
arises from a broad area on the outside of the rib cage on 12 th rib to 5th rib
zig-zag line of origin of external oblique fits in with the line of the origin of serratus anterior
is one continuous muscle but we’ll look at the muscle in 2 parts; a posterior part that arises
from 12th to 10th rib and, anterior part; arises from 9th to 6th rib + ends in external oblique
aponeurosis; fuses with the combined aponeuroses of the other 2 muscles to form =>
anterior rectus sheath
external oblique aponeurosis has long free lower border between the anterior superior iliac
spine and pubic tubercle
free lower border = inguinal ligament
part that arises from 10th to 12th ribs remains freshy from its origin to its insertion; inserts
along outer edge of anterior half of iliac crest
at the back: short free border between 12 th and the iliac crest
Actions of the 3 flat muscles
when the 3 contract together: raise pressure inside abdominal cavity
airway open: rise in intra-abdominal pressure pushes diaphragm upwards to leave the lungs
when breath is hold by closing larynx: flat muscles provide pressure that’s needed to expel
the contents of either rectum, bladder or uterus through their openings
when contracted individually: lateral flexion of lumbar spine + rotation of thoracic spine
Inside the abdominal cavity:
serous membrane that lines the abdominal cavity = parietal peritoneum beneath it: a
continuous layer of loose connective tissue = ilio-psoas fascia
on the inside of anterior abdominal wall = transversalis fascia
Inguinal region:
structure that passes obliquely through abdominal wall just above inguinal ligament = in
female; the round ligament of the uterus, in the male; the spermatic cord/ Funiculus
spermatocus (= the lifeline of the testis) passage that the spermatic cord passes through =
inguinal canal
Inguinal ligament
bifurcation = splitsing branches = taken spleen = milt intestine = darm
vessel = vat bile = gal colon = dikke darm suprarenal glands = bijnieren
Abdomen
Posterior part of abdominal wall:
Erector spinae muscles
arise from sacrum and a part from iliac crest
inserted on thoracic vertebrae and on backs of the ribs
enclosed on the front and back by the thoracolumbar fascia (=tendinous tissue)
layer on the back: arises from the spinous processes
layer on the front: arises from the transverse processes
the 2 layers of thoracolumbar fascia: fuse into thick layer along the border of erector spinae
Quadratus lumborum
lies in front of erector spinae muscles and their investing fascia
arises from 12th rib and the transverse processes of the upper 3 lumbar vertebrae
inserted on the most medial part of iliac crest and transverse process of L5
assists in producing lateral flexion
Psoas major
lies medial to quadratus lumborum
arises from transverse processes, vertebral bodies and intervertebral disks from T12 to L5
runs down across the ala of sacrum, across the sacroiliac joint and along the pelvic brim
function: flexion of hip joint
Iliacus muscle
fills the iliac fossa
arises from wide area on the wing of the ilium
down medial fibers of iliacus and lateral fibers of psoas major join forming a single muscle belly
iliopsoas: runs beneath the inguinal ligament and passes backwards to insert on lesser trochanter
of the femur
iliacus & psoas muscles are covered by the iliopsoas fascia is covered in turn by the membrane
which lines the abdominal cavity = the peritoneum
function: flexion of the hip joint
Diaphragm = highest part of abdominal wall all around
makes dome-shaped partition separating the abdominal cavity below from the thoracic
cavity above
At the bottom, the middle part of the posterior abdominal wall formed by the vertebral bodies
becomes continuous with the wall of the pelvic cavity at the sacral promontory.
Psoas muscle: stands away on each side from the vertebral bodies like a pillar
,aponeurosis = a tendon that’s in the form of a sheet tendon = pees cavity = holte
bifurcation = splitsing branches = taken spleen = milt intestine = darm
vessel = vat bile = gal colon = dikke darm suprarenal glands = bijnieren
Iliacus muscles with their investing fascia: form a continuation of the posterior abdominal wall
that slopes downward forward& inward ending at the inguinal ligament
Lowest part of the abdominal wall = the inguinal ligament
Lateral and anterior part of abdominal wall:
fill in the huge gap that’s created by the costal margin above, the edge of the thoracolumbar
fascia behind, the iliac crest, the inguinal ligament and the pubic crest below
Rectus abdominis
runs vertically next to the midline from the lower anterior ribs to the pubis
very long muscle
wide at the top& tapering to a more narrow attachment at the bottom
arises from the 5th, 6th and 7th costal cartilages
inserted on the pubic crest
divided on the front by bands of tendon tendinous intersections (3 or 4) they go about
halfway through the muscle
function: flexion of lumbar spine (in opposition to the erector spinae muscles)
important static effect: keeping the lumbar spine straight at times when the force of gravity
tends to extend it
enclosed on the front and back by tendinous envelope that’s formed by aponeuroses of the 3
flat muscles 2 layers of rectus sheath: 1. posterior rectus sheath; ends about ¾ of the way
down the muscle (the lower border = arcuate line), 2. anterior rectus sheath; extends from
the costal margin to the pubis + is firmly attached to the tendinous intersections => both
layers insert into dense mid-line band of tendinous tissue = linea alba; it extends from
xiphoid process to the pubis
3 large flat muscles: (flat may not be the best word bc in the vertical plane they’re curved)
1. Transversus abdominis (= innermost of the 3)
fibers all run in the same transverse direction (expect the lowest ones which run obliquely
downwards)
at the top: its fibers arise from the inner aspect of the costal margin from 6 th rib to 12th rib
between 12th rib and ilium: arises from the edge of thoracolumbar fascia
below: arises from the inner aspect of iliac crest
the lowest fibers arise from a thickening of iliopsoas fascia
has a short free lower border
muscle fibers end in transversus aponeurosis (= broad sheet of tendon); fuses with the
overlying internal oblique muscle to form one aponeurotic layer
2. Internal oblique
arises from thoracolumbar fascia& from iliac crest
lowest fibers: arise, like those of transversus, from a thickening of the iliopsoas fascia
has a short free lower border
fans out => so that its highest and lowest fibers run in different directions
, aponeurosis = a tendon that’s in the form of a sheet tendon = pees cavity = holte
bifurcation = splitsing branches = taken spleen = milt intestine = darm
vessel = vat bile = gal colon = dikke darm suprarenal glands = bijnieren
back: the fibers run steeply upwards then they run less steeply then they’re
transverse& then, towards the inguinal region, they run downward
highest fibers: insert on lowest 3 ribs
remaining fibers: end in internal oblique aponeurosis; fuses on the underside with the
transversus aponeurosis + joined on its outer aspect by external oblique aponeurosis
the combined aponeurotic layer divides at the edge of the rectus into 2 layers, one passing
behind and one passing in front of the rectus
below: the combined layer doesn’t divide but passes entirely in front of the muscle
3. External oblique (= outermost of the 3)
fibers spiral downwards and forwards at the side downwards and medially in front
arises from a broad area on the outside of the rib cage on 12 th rib to 5th rib
zig-zag line of origin of external oblique fits in with the line of the origin of serratus anterior
is one continuous muscle but we’ll look at the muscle in 2 parts; a posterior part that arises
from 12th to 10th rib and, anterior part; arises from 9th to 6th rib + ends in external oblique
aponeurosis; fuses with the combined aponeuroses of the other 2 muscles to form =>
anterior rectus sheath
external oblique aponeurosis has long free lower border between the anterior superior iliac
spine and pubic tubercle
free lower border = inguinal ligament
part that arises from 10th to 12th ribs remains freshy from its origin to its insertion; inserts
along outer edge of anterior half of iliac crest
at the back: short free border between 12 th and the iliac crest
Actions of the 3 flat muscles
when the 3 contract together: raise pressure inside abdominal cavity
airway open: rise in intra-abdominal pressure pushes diaphragm upwards to leave the lungs
when breath is hold by closing larynx: flat muscles provide pressure that’s needed to expel
the contents of either rectum, bladder or uterus through their openings
when contracted individually: lateral flexion of lumbar spine + rotation of thoracic spine
Inside the abdominal cavity:
serous membrane that lines the abdominal cavity = parietal peritoneum beneath it: a
continuous layer of loose connective tissue = ilio-psoas fascia
on the inside of anterior abdominal wall = transversalis fascia
Inguinal region:
structure that passes obliquely through abdominal wall just above inguinal ligament = in
female; the round ligament of the uterus, in the male; the spermatic cord/ Funiculus
spermatocus (= the lifeline of the testis) passage that the spermatic cord passes through =
inguinal canal
Inguinal ligament
