Abdomen Lecture Notes Pt. 2 Flashcards
Receives tributaries from the SMV and IMV
Hepatic Portal Vein
The umbilicus and iliac crest are located at L4, but their cutaneous dermatome is
T10
The transpyloric plane cuts the kidneys in half and is also where part of the pancreas is. It is at the level of
L1
Divides the 4 quadrants horizontally
Transumbilical plane (L4)
Provide better differentiation between soft tissues
MRI’s
Appear as cross sections as viewed from the FOOT of a patient
-So observers left is the patients right
CT scans
In a CT, we want to find the vertebral body first. then just anterior to the vertebral body is the
Abdominal aorta
Then just to the right of the abdominal aorta is the
IVC
The abdominal aorta gives off the left renal artery at
L1-L2
The abdominal aorta gives off the left gonadal artery at
L2
In a CT of T12, we can clearly see the
Left colic flexure
Travels between the abdominal aorta and superior mesenteric artery
Left renal vein and uncinate process of duodenumm
Branches off posterior to the IVC
Right renal artery
Just inferior to where the SMV and splenic vein come together, we have the
Hepatic Portal Vein
We can see the pyloris of the stomach as we move into the 1st part of the duodenum in a CT at the level of
L1-L2
Each of the 3 prevertebral ganglion are associated with one of the big 3
Aorta branches (celiac trunk, SMA, IMA)
The only splanchnic nerves carrying parasympathetic fibers
Pelvic splanchnics
Ganglia in the wall of the organ we are innervating that are found in plexuses
Terminal ganglia
Provide EXTRINSIC innervation of the gut
Sympathetic and parasympathetic innervation
The enteric nervous system is intrinsic, meaning it is located in the walls of the
Bowel
The enteric nervous system is made up of which two major plexuses?
- ) Myenteric Plexus
2. ) Submucosal Plexus
Extrinsic nerve fibers run on blood vessels leading to the
Bowel
When the outer longitudinal layer of bowel muscle relaxes in front of the bolus and the inner circular layer contracts behind the bolus we get
Peristalsis
Disease where there are regions of the bowel without myernteric or submucosal plexus’s
-most common region is rectosigmoidal plexus
Aganglionic Megacolon (Hirschsprung’s)
In Hirschsprung’s, the constricted segment is the aganglionic segment because the extrinsic nerve fibers cause
Tonixc contraction
Allows relaxation of the colon
Intrinsic innervation
Have to go through the diaphragm to get into the abdomen for abdominal innervation
-Range from T5-T9
Greater thoracic splanchnics
The transition from midgut to hindgut happens immediately after the
Proximal 2/3 of transverse colon
Because of rotation of the forgut, where is the
- ) Left Vagus nerve
- ) Right vagus nerve
- ) Anterior
2. ) Posterior
Pass through the celiac ganglion and are distributed on the celiac trunk to organs
Posterior Vagal nerve fibers
There is communication between the celiac, SM, and IM plexuses which allows the vagus nerve to provide parasympathetic innervation from
Esophagus to proximal 2/3 of transverse colon
You could cut or burn segments of the bowel without feeling it. But what would you feel?
Ischemia or pressure
Dull and poorly localized pain due to the fact that the bowel has less nerve endings than skin
Visceral pain
The dermatomal segment for the umbilicus is
T10
What is the lowest dermatomal segment of the gut for visceral pain?
L1