Download POSTERIOR ABDOMINAL WALL

POSTERIOR ABDOMINAL WALL
(BOUNDARIES, MUSCLES, FASCIAE)
LEARNING OBJECTIVES
At the end of the lecture, students should be able to know:
Structures forming posterior abdominal wall.
Details of muscles of posterior abdominal wall.
Attachments of lumber fascia.
STRUCTURES
Five lumbar vertebrae.
Vertebrae are separated by the inter vertebral discs.
Psoas , Quadratus Lumborum,Iliacus muscles.
MUSCLES
PSOAS MAJOR
ORIGIN
(a). Bodies of lumber vertebrae.
(b). Lumber intervertebral discs.
(c). Fibrous arches spanning the concavities of sides of upper vertebral bodies.
(d). Medial ends of all the lumber transverse processes.
ACTIONS
 Power flexor of hip joint.
 Lateral flexor of vertebral column.
 With iliacus and their fellows of opposite side it assist in the flexion of the
trunk produced by anterior abdominal wall muscles.
INSERTION
 One continuous attachment between lower borders of T-12 to the
upper border of L-5 vertebrae.
 Passes down along the brim beneath the inguinal ligament.
 Tendon is attached to the lesser trochanter of femur.
PSOAS FASCIA
 Invests the surface of muscles.
 Attached to the vertebral bodies, fibrous arches and transverse process
and iliopubiceminence.
 Retains pus.
 Cold abscess.
 It is not part of lumbar fascia.
 Its lateral edges blends with anterior layers of that fascia (over quadratus lumborum muscle).
 Psoas fascia thicken from body of L1 (or L2) to transverse process of L1 to from medial arcuate
ligament.
NERVES SUPPLY
First three lumber nerves (mainly L2).
QUADRATUS LUMBORUM
 Flat sheet
 Lying in the deep paravertebral gutter.
 Edge to edge with psoas medially and transverse abdominis laterally.
ORIGIN
 Transverse process of L5 vertebrae.
 Strong iliolumbar ligament.
 Short length of adjoining iliac crests.
ACTION
 Prevent diaphragm from elevating 12 th rib during inspiration.
 Depress 12th rib it aids descent of contracting diaphragm.
 Lateral flexor of lumbar spine.
NERVE SUPPLY
Subcostal nerve.
Upper three or four lumbar nerves.
ILIACUS
ORIGIN
 Upper 2/3rd of iliac fossa up to the inner lip of iliac crest and from
anterior sacroiliac ligament.
 Iliacus muscles is covered by iliac fascia.
 Attached to the bone at the margins of muscle and to inguinal ligament.
 Fascia is continuous with psoas fascia.
NERVE SUPPLY: Femoral nerve L2,L3
FASCIA
 Each of the muscle of posterior abdominal wall is covered by fascia.
 Dense and unyielding.
 Fascia blends at margins of muscles.
 Anterior and middle layer occupy lumbar region.
 Posterior layer extends above to the neck and below to the dorsal surface of
sacrum.
 Quadratus lumborum occupy the anterior compartment.
 Erector spinae fills the posterior compartment.
ANTERIOR LAYER
•
•
Extends from front of iliolumbar ligament and adjoining iliac crest to the lower
border of 12th rib.
Medially attached to the front of transverse process and adjoining attachments to
the psoas fascia.
•
Laterally it blends with middle layer along with lateral border of Quadratus
lumborum.
POSTERIOR LAYER
•
•
•
Lies over the whole erector spinae mass of muscle.
Attached medially to the spinous processes and supraspinous ligament of all
sacral lumber and thoracic vertebrae.
Its lateral margins extends upwards along the transverse tubercles from where it
slopes out wards to the 12 th rib.
THANK YOU
!!!!