Anatomy - Posterior Abdominal Wall

Question 1

Two large muscles on either side of the vertebral bodies

Answer 1

Psoas major and minor muscles

Question 2

Muscles lateral to the psoas major & minor in the posterior body wall

Answer 2

Quadratus lumborum muscle

Question 3

Muscle lateral and inferior to the psoas muscles

Answer 3

Iliacus muscle

Question 4

Name the 4 muscles forming the posterior body wall

Answer 4

• Psoas major & minor
• Quadratus lumborum
• Iliacus
• Transversus abdominis

Question 5

The quadratus lumborum attaches to…

Answer 5

the iliac crest

Question 6

The iliac crest lies on the edge of a bony surface called…

Answer 6

iliac fossa

Question 7

The psoas major attaches to…
The psoas minor attaches to…

Answer 7

• The psoas major attaches to the lesser trochanter.
• The psoas minor attaches to the superior pubic ramus.

Question 8

Name the structures going through the diaphragm (3)

Answer 8

1. Inferior vena cava (1 on picture)
2. Aorta (2 on picture)
3. Esophagus (3 on picture)

Question 9

Name the apertures through which the 3 structures pass through the diaphragm (and their spinal levels)

Answer 9

IVC: caval foramen (T8)
Esophagus: esophageal hiatus (T10)
Aorta: aortic hiatus (T12)

Question 10

Other than the IVC, what other structures pass through the caval foramen? (2)

Answer 10

• Right phrenic nerve
• Lymphatics

Question 11

Other than the esophagus, what other structures pass through the esophageal hiatus?

Answer 11

• Esophageal arteries & veins
• Left & right vagal trunks
• Lymphatics

Question 12

Other than the aorta, what other structures pass through the aortic hiatus? (2)

Answer 12

• Azygous vein
• Thoracic duct (lymphatic)

Question 13

What forms each of the following (in the diaphragm):
* caval foramen
* esophageal hiatus
* aortic hiatus

Answer 13

Caval foramen: hole in central tendon
Esophageal hiatus: right crus
Aortic hiatus: right and left crura

Question 14

Where does the left phrenic nerve penetrate the diaphragm?

Answer 14

It pierces the diaphragm on its own (it does not pass through one of the 3 main apertures)

Question 15

What tissue (ligament) surrounds the aortic hiatus?

Answer 15

Median arcuate ligament

Question 16

What ligament surrounds the psoas major & minor?

Answer 16

Medial arcuate ligament

Question 17

What ligament surrounds the quadratus lumborum muscle?

Answer 17

Lateral arcuate ligament

Question 18

What nerve innervates the diaphragm?

Answer 18

Phrenic nerve

Question 19

Why does the phrenic nerve continue past the diaphragm?

Answer 19

It also innervates the parietal peritoneum of the diaphragm in the abdominal cavity.

This is important, because if this peritoneum gets infected or inflammed, the phrenic nerve will relay that signal.

Question 20

The esophagus is surrounded by a loop of tissue called…

Answer 20

right crus (on the right of the aorta)

Question 21

Where is the left crus (relative to the aorta)?

Answer 21

on the left of the aorta

Question 22

Where is the right crus (relative to the aorta)?

Answer 22

On the right of the aorta (but it surrounds the esophagus)

Question 23

Which renal vein is longer?

Answer 23

Left renal vein is longer than the right renal vein

Question 24

The left renal vein passes between…

Answer 24

the superior mesenteric artery and aorta (risk of nutcracker syndrome for left kidney!)

Question 25

Name the arteries that supply the testis (males) or ovaries (females)

Answer 25

Gonadal arteries (branch off the aorta)

Question 26

The left gonadal vein drains into... The right gonadal vein drains into...

Answer 26

Left gonadal vein drains into the left renal vein. Right gonadal vein drains into the IVC. *Note: this means the left gonad is also susceptible to the nutrcracker syndrome!*

Question 27

The left suprarenal vein drains into... The right suprarenal vein drains into...

Answer 27

The left suprarenal vein drains into the left renal vein. The right suprarenal vein drains directly to the IVC.

Question 28

Lymphatic drainage follows...

Answer 28

arteries back to the aorta (drain lymph fluid back into the aorta)

Question 29

The autonomic nervous system is... a) an afferent (sensory) system b) an efferent (motor) system

Answer 29

b) an efferent (motor) system to the viscera

Question 30

The lumbar plexus emerges from behind the ...

Answer 30

psoas major muscle (deep to this muscle) *The lumbar plexus is somatic (afferent & efferent)*

Question 31

Ventral ramus vs Dorsal ramus

Answer 31

Dorsal ramus: Innervates deep back muscles Ventral ramus: Innervates everything in the body wall except the deep back muscles Both are somatic motor (efferent) nerves

Question 32

Name the 7 branches of the lumbar plexus and the spinal levels they originate from.

Answer 32

1. Subcostal nerve (T12) 2. Iliohypogastric nerve (L1) 3. Ilioinguinal nerve (L1) 4. Genitofemoral nerve (L1-L2) 5. Lateral cutaneous nerve of the thigh (L2-L3) 6. Femoral nerve (L2, L3, L4) 7. Obturator nerve (L2, L3, L4) *They innervate the muscles and skin of the lower extremities*

Question 33

What type of innervation does the vagus nerve carry?

Answer 33

Both efferent (parasympathetic) and afferent signals (visceral)

Question 34

The vagus nerve innervates... (2)

Answer 34

the foregut and midgut

Question 35

The hindgut is innervated by...

Answer 35

pelvic splanchnic nerves (S2-S4)

Question 36

Parasympathetic nervous system: Preganglionic nerves Postganglionic nerves Explain

Answer 36

Preganglionic: Originate in the spinal cord and synapse in the wall of the target organ (ganglion) Postganglionic: very short nerve that is activated by the preganglionic nerve to actually innervate the target organ

Question 37

Name the 2 parasympathetic nerves of the abdomen

Answer 37

Vagus nerve Pelvic splanchnic nerves

Question 38

What levels of the spinal cord give rise to sympathetic neurons of the abdomen?

Answer 38

T1 to L2

Question 39

What is the purpose of the sympathetic trunk?

Answer 39

Sympathetic neurons only exist from T1 to L2. However, they will synapse onto the sympathetic trunk, which allows them to branch out and innervate the entire body.

Question 40

Sympathetic neurons going to the SKIN (sweat glands, etc): To reach the sympathetic chain, pre-ganglionic sympathetic neurons follow... Post-ganglionic neurons will follow...

Answer 40

Pre-ganglionic sympathetic neurons will follow the white ramus communicans. Post-ganglionic neurons will follow the gray ramus communicans back to the spinal nerve and will course with somatic nerves to reach their target (skin).

Question 41

Sympathetic neurons going to the viscera will pass through the sympathetic chain WITHOUT synapsing, exiting via...

Answer 41

a splanchnic nerve

Question 42

Sympathetic pre-ganglionic neurons exit the sympathetic chain via a splanchnic nerve and will follow it to..

Answer 42

a preaortic ganglia, where they will synapse; post-ganglionic neurons will then follow arteries to reach their target.

Question 43

Sympathetic preganglionic neurons synapse onto...

Answer 43

preaortic/prevertebral ganglia

Question 44

Name the sympathetic ganglia located on... a) celiac trunk b) SMA c) IMA d) between aorta and renal artery

Answer 44

a) celiac ganglion b) superior mesenteric ganglion c) inferior mesenteric ganglion d) aorticorenal ganglion

Question 45

Where does the greater splanchnic synapse?

Answer 45

On the celiac ganglion

Question 46

Name the 3 splanchnic nerves of the toracic cavity

Answer 46

Greater splanchnic nerve Lesser splanchnic nerve Least splanchnic nerve

Question 47

The adrenal cortex is derived from... The adrenal medulla is derived from...

Answer 47

The adrenal cortex is derived from mesoderm. The adrenal cortex is derived from neural crest cells.

Question 48

The adrenal medulla can be thought of as a modified...

Answer 48

sympathetic ganglion (it is derived from the same embryonic tissue that forms postganglionic sympathetic neurons)

Question 49

Neurons innervating the adrenal gland synapse directly onto...

Answer 49

the adrenal medulla (no post-ganglionic neurons!)

Question 50

The general visceral afferent nerves carry...

Answer 50

sensory impulses from the viscera to the brain

Question 51

Describe the path of the general visceral afferent nerves from the viscera to the CNS.

Answer 51

Originate in the viscera, follow the splanchnic nerve to the sympathetic chain and continue up the white ramus communicans and then enter the sensory route to reach the spinal cord (same path as efferents but in the opposite direction).