vertebrae, and intervening
intervertebral discs
branches
of L1-L4
nerves
trunk in sitting position; acting
inferiorly with iliacus, flexes trunk
Iliacus Superior two thirds of iliac
fossa, ala of sacrum, and
anterior sacroiliac
ligaments
Lesser trochanter
of femur and
shaft inferior to it,
and to psoas
major tendon
Femoral
nerve (L2-
L4)
Iliolumbar artery Flexes hip and stabilizes hip joint;
acts with psoas major
Quadratus
lumborum
Medial half of inferior
border of 12th rib and tips
of lumbar transverse
processes
Iliolumbar
ligament and
internal lip of iliac
crest
Ventral
branches
of T12 and
L1-L4
nerves
Iliolumbar artery Extends and laterally flexes vertebral
column; fixes 12th rib during
inspiration
DiaphragmXiphoid process, lower six
costal cartilages, L1-L3
vertebrae
Converge into
central tendon
Phrenic
nerve (C3-
C5)
Pericardiacophrenic
musculophrenic,
superior and
inferior phrenic
arteries
Draws central tendon down and
forward during inspiration
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Fascia
Superficial fascia: single layer
Deep fascia-a very thin layer investing the most superficial muscles.
Transversalis fascia (endoabdominal fascia)
Endoabdominal fat separates the transversalis fascia from the parietal peritoneum
Psoas sheath
Fascia covering the psoas muscle
Attaches to lumbar vertebrae and pelvic brim
Thickened superiorly to form the medial arcuate ligament-a site of origin of the muscle of the diaphragm
Fascia of quadratus lumborum
Fuses medially with psoas fascia
Thickened superiorly to form the lateral arcuate ligament-a site of origin of the muscle of the diaphragm
Thoracolumbar fascia (Section 2: Back and Spinal Cord)
Composed of anterior and posterior layers
Encloses the deep muscles of the back
Thick and strong in the lumbar region
Extends from 12th rib to iliac crest and continuous laterally with deep fascia of internal oblique and transversus abdominus
muscles
Muscles
Psoas major
Long and thick
Lies lateral, and is attached to, the lumbar vertebrae
Tendon passes deep to inguinal ligament to lesser trochanter of femur
Together with iliacus forms iliopsoas muscle, which flexes the hip, helps maintain erect posture
Lumbar plexus of nerves embedded within it
Iliacus
Attaches to superior two thirds of iliac fossa
Joins psoas to form iliopsoas
Quadratus lumborum
Thick quadrangular muscle of posterior wall
Extends from 12th rib and tips of lumbar transverse processes to iliac crest
Flexes and laterally extends vertebral column
Arteries of the posterior abdominal wall (Section 4-6: Abdomen-Visceral Vasculature)
Abdominal aorta
Origin of most of arteries supplying the posterior wall
Begins anterior to the body of T12 and ends at bifurcation of the common iliac arteries at L4
Common iliac artery
Follows the medial border of the psoas
Divides into internal and external iliac arteries at pelvic brim
External iliac
a. Gives off inferior epigastric and deep circumflex arteries
b. Exits under the inguinal ligament as the femoral artery
c. Supplies lower limb
Internal iliac artery supplies pelvis
Unpaired visceral branches of abdominal aorta
Celiac trunk (T12)
Superior mesenteric (L1)
Inferior mesenteric (L3)
Paired visceral branches
Suprarenal arteries (L1)
Renal arteries (L1)
Gonadal arteries (L2) (Note: gonadal arteries branch from the anterior aorta)
Paired parietal branches
Subcostal arteries (T12)