Posterior Abdominal Wall (Anatomy)

Question 1

Muscles of the posterior abdominal wall (4 muscles)

Answer 1

Psoas Major Muscle- hip flexor, with flexion of the vertebral column, lateral bending of vertebral column

Iliacus Muscle- stabilizes the hip & flexes the hip

Quadratus Lumborum Muscle- attaches to the 12th rib and maintains posture; also important for lateral sidebending

Diaphragm- pulls down the lungs; changes the thoracic pressure; allows for inspiration

Question 2

Psoas Abscess

Answer 2

Sign of pancreatitis; can lead to anorexia and loss of appetite

• Pain when flexing against the resistance of the hand of the physician
• Pain while side-bent and extension of the leg occurs

**For some reason, it is most common in patients that are susceptible to TB

Question 3

Fascia of the Posterior Abdominal Wall

Answer 3

Median Arcuate Ligament- around the aortic hiatus of the diaphragm; found around the tendinous arch of the crura

Medial Arcuate Ligament- tendinous connection that is right under the psoas major muscle

Lateral Arcuate Ligament-tendon over the quadratus lumborum muscle

Question 4

Diaphragm- Muscular Part (Embryology, attachment)

Answer 4

Muscular part of diaphragm:

• attaches to the sternum of the rib cage
• derived from the abdominal wall embryologically with specifc note to the hypomere (embryologically)

Question 5

Diaphragm- Costal Part (Embryologically, attachment)

Answer 5

Costal Part of the Diaphragm:

-attaches to the costal cartilages of ribs 6-12

Question 6

Diaphragm- Lumbar Part (Embryologically, attachment)

Answer 6

-attaches to medial and lateral arcuate ligaments of the backside of the diaphragm

Question 7

Central Tendon of the Diaphragm (Embryology)

Answer 7

Central Tendon comes from Septum Transversum of the diaphragm

Question 8

Crura of the Diaphragm (Embryology)

Answer 8

Dorsal Mesentary of the Esophagus:

• Right Crus- Around the Esophageal Hiatus
• Left Crus-lateral to the right crus on the left side of the diaphragm

Question 9

Apertures

Answer 9

Caval Opening- @ T8 (IVC + Right Phrenic Nerve passes through)

Esophageal Hiatus- @ T10 (Anterior/Posterior Vagal Trunk & Esophagus)

Aortic Hiatus- @ T12 (Aorta/ Thoracic Duct/ Azygos & Hemi-Azygos Vein)

Question 10

Crus Relationship & Anatomical Relationships to the Kidneys

Answer 10

Right Kidney is attached to the Right Crus of the Diaphragm

Right Kidney Anatomical Relationships: Anterior-
(Liver, Duodenum, Ascending Colon)

Left Kidney is attached to the Left Crus of the Diaphragm-
(Transverse Colon, Spleen, Pancreas, JEJUNUM, descending colon)

Question 11

What muscles do the kidneys stay in contact with?

Answer 11

transversus abdominus m, diaphragm (superiorly), quadratus lumborum m. (posterolaterally), psoas major m. (posteriomedially)

Question 12

What plane to find the kidneys?

Answer 12

Transpyloric Plane (L1)--> Renal Pelvis
        \+ Renal Vein--> most anterior structure
         \+Renal Artery--> most posterior structure to renal 
           vein

Question 13

What is the most important embryologically derived blood vessels to the kidneys and its importance?

Answer 13

The Accessory Renal Arteries–> these are very important because the blockage of these accessory renal arteries causes necrosis of a targeted area of the kidneys

Question 14

Anatomy of the Kidneys

Answer 14

Ureters–> Renal Pelvis–> Major Calyces (about 2-3 per Kidney) –> Minor Calyces (2-3 per branch of major calyces)

Question 15

Constrictions of the different parts of the urogenital system

Answer 15

Ureteropelvic Junction
Pelvic Brim (where ureter crosses the external iliac artery)
Ureter entrance to the Bladder

Question 16

Lymphatics of the Organs of GI System

Answer 16

Celiac Lymph Nodes- foregut

Superior Mesenteric Lymph Nodes- midgut

Inferior Mesenteric Lymph Nodes- hindgut

Celiac, Superior Mesenteric, Inferior Mesenteric–> Lumbar Lymph Nodes–> Cysterna Chyli–> Thoracic Duct

Question 17

Nerves of the Abdominal Cavity

Answer 17

Psoas Major Muscle- Genitofemoral Nerve

Under the 12th Rib- Subcostal Nerve

a.) Iliohypogastric Nerve- transverses the quadratus
lumborum
b.) Ilioinguinal Nerve- runs along the iliac spine
**pierces the transversus abdominus muscle;
descends from the medial arcuate ligament

Deeper structures:
a.) Runs along the Iliac Fossa- lateral femoral cutaneous
nerve
b.) Femoral Nerve- HUGE; runs through the inguinal ligament
c.) Obturator Nerve- Runs through the obturator foramen

Lumbosacral Trunk–> runs along the Ala of the sacrum

Question 18

Functions of those Nerves

Answer 18

Iliohypogastric Nerve:
Sensory: sensation of the posterolateral gluteal skin &
skin in the pubic region

Ilioinguinal Nerve:
Sensory:
sensation to the upper medial thigh

 Male:  skin over the root of the penis, anterior scrotum
 Female: mons pubis, labium majus

Genitofemoral Nerve:
Sensory:
Genital Branch: skin of the anterior scrotum/ skin of
mons pubis
Femoral Branch: skin of anterior upper thigh

Lateral Cutaneous Nerve of Thigh:
Sensory:
skin of anterior and lateral thigh to the knee

Obturator Nerve:
Motor: adductor muscles of the thigh
Sensory: medial aspect of the thigh

Femoral Nerve:
Motor: movement of the hip flexors
Sensory: skin of the anterior thigh & medial surface of
the leg