Week 16 - Posterior Abdominal Wall & Kidney Flashcards
* Be familiar with the anatomy of the posterior abdominal wall * Describe the anatomy, innervation and functions of the muscles of the posterior abdominal wall * Be able to discuss their functional relationship with the diaphragm and roles in posture, ventilation and voiding of abdominal/thoracic contents * Describe the anatomical features of the kidneys: position, extent, relations, hilum, and peritoneal coverings * Describe and relate the internal structure of the kidneys: cortex, medulla and
What is the posterior abdominal wall fascia?
Continuous layer of endoabdominal fascia
It is located between parietal peritoneum & muscles and is continuous with transversalis fascia.
What structure does the posterior abdominal wall fascia connect to medially?
Lumbar vertebrae.
What does the posterior abdominal wall fascia connect to laterally?
Thoracolumbar fascia and quadratus lumborum.
What forms the medial arcuate ligament?
A thickening of the fascia overlying the psoas major muscle
What does the posterior abdominal wall fascia connect to inferiorly?
Iliac fascia covering iliacus.
How many layers does the thoracolumbar fascia have?
Three layers.
Where does the posterior layer of thoracolumbar fascia lie?
Between the 12th rib and iliac crest.
What does the anterior layer of thoracolumbar fascia attach to?
- Anterior aspect of transverse processes of lumbar vertebrae
- 12th rib
- Iliac crest.
What does the anterior layer of thoracolumbar fascia thicken to form?
Lateral arcuate ligament.
What is the lumbar plexus composed of?
Anterior rami of L1-5.
What are the branches of the lumbar plexus?
- Iliohypogastric
- Ilioinguinal
- Genito-femoral
- Lateral femoral cutaneous of the thigh
- Femoral
- Obturator
- Lumbosacral trunk.
(I)ndecent (I)an (G)ets (L)aid (O)n (F)ridays (L)uckily
Which lumbar plexus branch pierces the psoas major?
Genito-femoral.
What does the iliohypogastric nerve supply?
Skin of the lower abdomen and part of the buttocks.
What does the lateral femoral cutaneous nerve supply?
Skin on anterolateral surface of thigh.
What does the femoral nerve innervate?
- Iliacus
- Flexors of hip
- Extensors of knee
What is the role of the obturator nerve?
Innervates adductor muscles of the medial thigh.
What forms the sacral plexus?
Lumbosacral trunk with anterior rami of S1-S4.
Also receives contributions from L4 & L5
What are the branches of the abdominal aorta?
- Coeliac artery: Supplies blood to the stomach, liver, and pancreas
- Superior mesenteric artery: Supplies blood to the small intestine
- Inferior mesenteric artery: Supplies blood to the large intestine
- Renal arteries: Supply blood to the kidneys
- Common Iliac arteries: Supply blood to the legs and pelvis
- Inferior phrenic arteries: Supply the diaphragm
- Adrenal arteries: Supply the adrenal glands
- Lumbar arteries: Supply the lower back muscles, joints, and skin
- Median sacral arteries: Supply the sacrum and lumbar vertebrae
- Gonadal arteries: Supply the gonads (ovaries in women and testes in men)
What branches does the external iliac give off?
- Inferior epigastric
- Deep circumflex iliac branches
- Enters thigh as femoral artery
The external iliac artery is a major blood vessel that supplies blood to the lower limbs.
At what level is the inferior vena cava formed?
L5
The inferior vena cava is formed by the union of the common iliac veins.
What structures does the inferior vena cava separate from the portal vein?
Lesser sac
The lesser sac is a cavity in the abdomen that is behind the stomach.
What is the course of the inferior mesenteric vein?
- Tributary of portal system
- Begins as superior rectal vein
- Joins splenic vein behind pancreas
The inferior mesenteric vein drains blood from the large intestine.
Where does the splenic vein begin?
Hilum of spleen
The splenic vein collects blood from the spleen and other abdominal organs.
What veins join the splenic vein?
- Short gastric veins
- Left gastro-omental veins
These veins contribute to the formation of the portal vein.
What is the function of the superior mesenteric vein?
Joins splenic vein to form portal vein
The superior mesenteric vein drains blood from the small intestine and parts of the large intestine.
What do preaortic lymph nodes drain from?
- Lower 1/3 of esophagus to 1/2 way down anal canal
Including:
- Spleen
- Pancreas
- Gallbladder
- Greater part of liver
Preaortic lymph nodes are critical in draining lymph from the abdominal organs.
What is the thoracic duct?
The thoracic duct is the largest lymphatic vessel in the body
Begins in abdomen as cisterna chyli
What is the location of the kidneys?
Retroperitoneally in abdomen, extending from T12 to L3
The right kidney is lower than the left due to the liver’s position.
What layers cover the kidneys?
- Renal capsule
- Perirenal fat
- Renal fascia (Gerota’s fascia)
- Pararenal fat
Internal to External
These coverings provide protection and support to the kidneys.
What are the internal structures of the kidney?
- Outer cortex
- Inner medulla
- Renal sinus
The kidney’s internal structure is essential for its filtering function.
What is the arterial supply of the kidneys?
- Renal arteries
- Segmental arteries
- Lobar arteries
- Interlobar arteries
- Arcuate arteries
- Interlobular arteries
- Afferent glomerular arterioles
This complex arterial supply is crucial for providing blood to the renal tissue.
True or False: The left kidney is anteriorly related to the liver.
False
The left kidney is anteriorly related to the suprarenal gland, spleen, stomach, pancreas, and other structures.
Fill in the blank: The renal fascia encloses the kidneys and _______.
[suprarenal glands]
The renal fascia helps to anchor the kidneys in place.
What is the order of structures entering and leaving the hilum of the kidney from anterior to posterior?
Vein, Artery, Ureter
What is the course of the ureter?
- Muscular ducts that run inferiorly from the apices of the renal pelvis
- Pass over the pelvic brim at the bifurcation of common iliac arteries
- Run along the lateral wall of the pelvis
- And, enter the urinary bladder
Describe the impact of malnutrition or starvation on the perirenal fat.
Less fat, kidney moves more inferiorly
What are the constrictions of the ureters?
- Pelvic-ureteric junction
- Where the ureters cross the brim of pelvic inlet
- During passage through the wall of urinary bladder
What is the lymphatic drainage of the kidneys?
Kidney drains to the right and left lumbar nodes
What is the nerve supply of the kidney?
Renal sympathetic plexus; afferent fibers travel through renal plexus to enter the spinal cord in T10-12 nerves
Why do you experience loin to groin pain with kidney problems?
Visceral afferent fibers convey pain sensation to T10-L1; groin dermatome is L1
What is the structure and shape of the suprarenal (adrenal) glands?
Surrounded by connective tissue containing perinephric fat, enclosed by renal fascia, separated from the kidney by a thin septum; right gland is pyramidal and left is crescent-shaped
What are the parts of the adrenal gland?
- Cortex: derived from mesoderm, secretes corticosteroids & androgens
- Medulla: mass of nervous tissue, derived from neural crest cells, associated with sympathetic nervous system, secretes catecholamines
Fill in the blank: The adrenal cortex is derived from _______.
[mesoderm]
What are the sources of adrenal arteries?
- Superior adrenal arteries: from inf phrenic arteries
- Middle adrenal arteries: from abdominal aorta
- Inferior adrenal arteries: from renal arteries
How does venous drainage occur in the adrenal glands?
From large suprarenal veins; short right suprarenal vein drains into IVC and longer left suprarenal vein joins with inferior phrenic vein to drain into left renal vein
What is the origin of the Psoas Major?
- Vertebral bodies T12-L4
- Transverse processes L1-5
This includes intervertebral discs T12-L4.
Where does the Psoas Major insert?
Lesser trochanter of the femur
It becomes the iliopsoas tendon.
What are the functions of the Psoas Major?
- Hip flexion
- Lateral rotation of thigh
- Lateral rotation of trunk
These functions are crucial for movements involving the hip and trunk.
What is the innervation of the Psoas Major?
Anterior rami of L1-L3
What is the blood supply to the Psoas Major?
Lumbar branch of iliolumbar
This artery is essential for vascularizing the muscle.
What is the origin of the Psoas Minor?
Vertebral bodies T12-L1
Where does the Psoas Minor insert?
Iliopubic eminence
What is the innervation of the Psoas Minor?
Anterior rami of L1
What is the blood supply to the Psoas Minor?
Lumbar arteries
What is the origin of the Quadratus Lumborum?
- Iliac crest
- Iliolumbar ligament
This muscle has multiple points of origin.
What occurs with bilateral contraction of the Quadratus Lumborum?
Fixes ribs 12 during inspiration & trunk extension
What occurs with unilateral contraction of the Quadratus Lumborum?
Lateral flexion of trunk
What is the innervation of the Quadratus Lumborum?
Anterior rami of L1-4
What is the blood supply to the Quadratus Lumborum?
- Lumbar arteries
- Deep circumflex iliac arteries
- Subcostal arteries
- Median sacral artery
These arteries provide necessary blood flow to the muscle.
What is the origin of the Iliacus?
Iliac fossa of the ilium
Where does the Iliacus insert?
Lesser trochanter
What are the functions of the Iliacus?
Thigh & trunk flexion at the hip joint
What is the innervation of the Iliacus?
Femoral nerve L2-4
What is the blood supply to the Iliacus?
- Iliolumbar arteries
- Deep circumflex iliac arteries
- Obturator arteries
- Femoral arteries
These vessels are critical for supplying the muscle.
What is the Insertion of the Quadratus Lumborum?
- Inferior border of rib 12
- Transverse process of L1-L4
