Posterior abdominal wall Flashcards
Overview of structures
- bony components
- Muscles and fascia
- Structures
Bony components
5 lumbar vert and IVD’s
Muscles and fascia
Psoas major & minor, iliacus, quadratus lumborum, transversus abdominus, diaphragm
Structures
Nerves
Arteries
Veins
Lymphatics
Middle of posterior abdominal wall, mostly close to bodies of lumbar vertebrae
How many lumbar vert?
5
Spines of lumbar vert are
short and horizontal
bodies of lumbar vert are
large and kidney
shaped: weight bearing
Facets orientation of lumbar vert allows:
flexion, extension and lateral
flexion, no rotation.
Pelvic brim (inlet)
Extends from the sacral promontory posteriorly to the symphasis pubis anteriorly
Pelvis major is the part of the pelvis
Located superior to the pelvic brim
- abdominal structures
Pelvic minor is the part of the pelvis
Located inferior to the pelvic brim
- pelvic organs
Three parts of the pelvic brim are:
- Anterior border of the ala of the sacrum (sacral part)
- Arcuate line of the ilium (iliac part)
- Pecten pubis and pubic crest (pubic part)
The pelvis has 4 articulations
- Two synovial joints
[ Sacroiliac joints] - Two symphysis joints (symphysis pubis and sacrococcygeal joint)
Sacrum & coccyx consist of
Five fused vertebrae.
Sacrum & coccyx features
Triangular with apex inferior (articulates
with coccyx).
* Base superior (body articulates with L5).
* Ala laterally (represents transverse processes).
* Concave anterior surface & convex posterior surface.
* Anterior and posterior sacral foramina: for anterior & posterior rami of spinal nerves.
* Auricular surface: articulates with pelvic bones.
* Sacral hiatus (injection of anesthetic).
* Coccyx: 3 or 4 fused vertebrae.
Psoas major
Psoas major origin/prox:
lateral surface of bodies, intervertebral discs and transverse processes of lumbar vertebrae (& T12)
Psoas major insertion/distal:
lesser trochanter of femur
Psoas major innervation
Anterior rami of L1, L2, L3
Psoas major action
Flexes thigh at hip
Psoas minor
Psoas minor origin/prox:
lateral surface of bodies of T12 & L1, intervertebral disc
Psoas minor insertion/distal:
Pectineal line, iliopubic eminence
Psoas minor innervation
Anterior rami of L1
Psoas minor action
weak flexor of vertebral column
Quadratus lumborum
Quadratus lumborum origin/prox:
Transverse process of L5, iliolumbar ligament, iliac crest
Quadratus lumborum insertion/distal:
Transverse processes of L1-L4, inferior border of rib 12
Quadratus lumborum innervation
Anterior rami of T12, L1, L2, L3, L4
Quadratus lumborum action
Depresses and stabilizes rib 12, lateral flexion of trunk.
Iliacus
Iliacus prox:
anterior iliac fossa of os coxa
Iliacus distal:
Anterior lesser trochanter of femur
Iliacus innervation
Femoral nerve
Iliacus action
Flexes thigh at hip
Diaphragm
* Position varies (breathing, posture, abdominal viscera).
Diaphragm
Structure & attachments:
- Central tendon
- Surrounding muscular part
Sternal
Costal
Lumbar
Median, medial and lateral arcuate ligaments of diaphragm
- Blood supply (inferior surface) of diaphragm
inferior phrenic arteries & veins
Nerve supply of diaphragm:
phrenic nerves (C3, C4, C5).
Diaphragm
* Openings
- Caval opening: IVC: T8
- (O)Esophageal hiatus: T10
- Aortic hiatus: T12
Retroperitoneal space:
behind peritoneum.
Retroperitoneal structures:
peritoneum on anterior side only.
Fascia lining posterior abdominal wall is continuous
with fascia that lines transversus abdominis muscle.
Retroperitoneal fascia
* Lies between parietal peritoneum & muscles.
* Named according to structure it covers:
o Psoas fascia:
* Forms medial arcuate ligament - thickening
of fascia.
* Fuses laterally with quadratus lumborum and thoracolumbar fascias.
* Continuous inferiorly with iliac fascia.
o Quadratus lumborum fascia (anterior layer of
thoracolumbar fascia).
* Forms lateral arcuate ligament.
Structures on posterior abdominal wall
Nerves
lumbar plexus, sympathetic nerves.
Structures on posterior abdominal wall
Arteries
Abdominal aorta & branches.
Structures on posterior abdominal wall
Veins
Inferior vena cava & tributaries.
Structures on posterior abdominal wall
Lymph nodes
Lumbar plexus
https://www.youtube.com/watch?v=RYk7rbgK1Z4
Abdominal Aorta
- Starts at T12 – aortic hiatus.
- Ends at L4 – bifurcation into left and right common iliac arteries.
- Anterior to vertebral bodies, IVC on right hand side.
- Left lumbar veins pass posterior to aorta.
- Common iliac arteries – medial border of psoas major to pelvic brim:
- Divide into external and internal iliac arteries.
Abdominal Aorta - Branches
Three vascular planes:
- Anterior midline - Unpaired visceral
branches – digestive system – celiac, superior mesenteric, inferior mesenteric arteries. - Lateral - Paired visceral branches – urogenital and endocrine organs – suprarenal, renal, gonadal arteries.
- Posterolateral – Paired parietal branches – diaphragm, body wall – subcostal, inferior phrenic, lumbar arteries
Inferior Vena Cava
- Begins anterior to L5: union of common iliac veins.
- Ascends on right side of L3, L4 &L5 vertebral bodies, on the right psoas major, on the right of the aorta.
- Passes through the caval opening of the diaphragm at T8.
- Tributaries: correspond to the paired visceral and paired parietal branches of abdominal aorta.
- Unpaired branches from digestive tract – hepatic
portal vein. - Left inferior phrenic & left gonadal vein drain
into left renal vein. - Ascending lumbar & azygous veins connect IVC
and SVC.
Lymphatic drainage
- Lymph nodes & lymphatic vessels – lie along aorta, IVC, and iliac vessels.
- Common iliac nodes: lymph from external & internal lymph nodes
–> lumbar lymph nodes. - Lymph from digestive organs: pre- aortic lymph nodes:celiac, superior mesenteric, inferior mesenteric (around the origins of the arteries).
- Intestinal lymphatic trunks: pre-aortic nodes.
- Lumbar lymphatic trunks: from lumbar nodes.
- Thoracic duct: all the lymph from below the diaphragm.
➢Inferior end – dilation called cisterna chyli – anterior to L1, L2.
➢Ascends through aortic hiatus in diaphragm.
➢Ultimately enters venous system: junction of left subclavian & internal jugular veins.
Slide 27 - 29
