Anatomy - Posterior Abdominal Wall Flashcards
Two large muscles on either side of the vertebral bodies
Psoas major and minor muscles
Muscles lateral to the psoas major & minor in the posterior body wall
Quadratus lumborum muscle
Muscle lateral and inferior to the psoas muscles
Iliacus muscle
Name the 4 muscles forming the posterior body wall
- Psoas major & minor
- Quadratus lumborum
- Iliacus
- Transversus abdominis
The quadratus lumborum attaches to…
the iliac crest
The iliac crest lies on the edge of a bony surface called…
iliac fossa
The psoas major attaches to…
The psoas minor attaches to…
- The psoas major attaches to the lesser trochanter.
- The psoas minor attaches to the superior pubic ramus.
Name the structures going through the diaphragm (3)
- Inferior vena cava (1 on picture)
- Aorta (2 on picture)
- Esophagus (3 on picture)
Name the apertures through which the 3 structures pass through the diaphragm (and their spinal levels)
IVC: caval foramen (T8)
Esophagus: esophageal hiatus (T10)
Aorta: aortic hiatus (T12)
Other than the IVC, what other structures pass through the caval foramen? (2)
- Right phrenic nerve
- Lymphatics
Other than the esophagus, what other structures pass through the esophageal hiatus?
- Esophageal arteries & veins
- Left & right vagal trunks
- Lymphatics
Other than the aorta, what other structures pass through the aortic hiatus? (2)
- Azygous vein
- Thoracic duct (lymphatic)
What forms each of the following (in the diaphragm):
* caval foramen
* esophageal hiatus
* aortic hiatus
Caval foramen: hole in central tendon
Esophageal hiatus: right crus
Aortic hiatus: right and left crura
Where does the left phrenic nerve penetrate the diaphragm?
It pierces the diaphragm on its own (it does not pass through one of the 3 main apertures)
What tissue (ligament) surrounds the aortic hiatus?
Median arcuate ligament
What ligament surrounds the psoas major & minor?
Medial arcuate ligament
What ligament surrounds the quadratus lumborum muscle?
Lateral arcuate ligament
What nerve innervates the diaphragm?
Phrenic nerve
Why does the phrenic nerve continue past the diaphragm?
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.
The esophagus is surrounded by a loop of tissue called…
right crus (on the right of the aorta)
Where is the left crus (relative to the aorta)?
on the left of the aorta
Where is the right crus (relative to the aorta)?
On the right of the aorta (but it surrounds the esophagus)
Which renal vein is longer?
Left renal vein is longer than the right renal vein
The left renal vein passes between…
the superior mesenteric artery and aorta (risk of nutcracker syndrome for left kidney!)
Name the arteries that supply the testis (males) or ovaries (females)
Gonadal arteries (branch off the aorta)
The left gonadal vein drains into…
The right gonadal vein drains into…
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!
The left suprarenal vein drains into…
The right suprarenal vein drains into…
The left suprarenal vein drains into the left renal vein.
The right suprarenal vein drains directly to the IVC.
Lymphatic drainage follows…
arteries back to the aorta (drain lymph fluid back into the aorta)
The autonomic nervous system is…
a) an afferent (sensory) system
b) an efferent (motor) system
b) an efferent (motor) system to the viscera
The lumbar plexus emerges from behind the …
psoas major muscle (deep to this muscle)
The lumbar plexus is somatic (afferent & efferent)
Ventral ramus vs Dorsal ramus
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
Name the 7 branches of the lumbar plexus and the spinal levels they originate from.
- Subcostal nerve (T12)
- Iliohypogastric nerve (L1)
- Ilioinguinal nerve (L1)
- Genitofemoral nerve (L1-L2)
- Lateral cutaneous nerve of the thigh (L2-L3)
- Femoral nerve (L2, L3, L4)
- Obturator nerve (L2, L3, L4)
They innervate the muscles and skin of the lower extremities
What type of innervation does the vagus nerve carry?
Both efferent (parasympathetic) and afferent signals (visceral)
The vagus nerve innervates… (2)
the foregut and midgut
The hindgut is innervated by…
pelvic splanchnic nerves (S2-S4)
Parasympathetic nervous system:
Preganglionic nerves
Postganglionic nerves
Explain
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
Name the 2 parasympathetic nerves of the abdomen
Vagus nerve
Pelvic splanchnic nerves
What levels of the spinal cord give rise to sympathetic neurons of the abdomen?
T1 to L2
What is the purpose of the sympathetic trunk?
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.
Sympathetic neurons going to the SKIN (sweat glands, etc):
To reach the sympathetic chain, pre-ganglionic sympathetic neurons follow…
Post-ganglionic neurons will follow…
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).
Sympathetic neurons going to the viscera will pass through the sympathetic chain WITHOUT synapsing, exiting via…
a splanchnic nerve
Sympathetic pre-ganglionic neurons exit the sympathetic chain via a splanchnic nerve and will follow it to..
a preaortic ganglia, where they will synapse; post-ganglionic neurons will then follow arteries to reach their target.
Sympathetic preganglionic neurons synapse onto…
preaortic/prevertebral ganglia
Name the sympathetic ganglia located on…
a) celiac trunk
b) SMA
c) IMA
d) between aorta and renal artery
a) celiac ganglion
b) superior mesenteric ganglion
c) inferior mesenteric ganglion
d) aorticorenal ganglion
Where does the greater splanchnic synapse?
On the celiac ganglion
Name the 3 splanchnic nerves of the toracic cavity
Greater splanchnic nerve
Lesser splanchnic nerve
Least splanchnic nerve
The adrenal cortex is derived from…
The adrenal medulla is derived from…
The adrenal cortex is derived from mesoderm.
The adrenal cortex is derived from neural crest cells.
The adrenal medulla can be thought of as a modified…
sympathetic ganglion (it is derived from the same embryonic tissue that forms postganglionic sympathetic neurons)
Neurons innervating the adrenal gland synapse directly onto…
the adrenal medulla (no post-ganglionic neurons!)
The general visceral afferent nerves carry…
sensory impulses from the viscera to the brain
Describe the path of the general visceral afferent nerves from the viscera to the CNS.
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).
