Anatomy: where is my patient's abdominal pain? Flashcards
what are the three layers of anterolateral abdominal muscles, from superficial to deep?
(Rectus abdominus anteriorly)
External oblique
Internal oblique
Transversus abdominus
Does the peritoneum contain sensory receptors?
Yes
Where does the inferior epigastric artery arise from?
The external iliac artery, just medial to the deep inguinal ring
Where does the inferior epigastric run?
In the anterior abdominal wall, just deep to the rectus abdominus
What do the omenta divide the peritoneal cavity into?
A greater sac and a lesser sac that communicate with each other through the omental foramen
What lies within the free edge of the lesser omentum?
The portal triad
Which ligament attaches the liver to the anterior abdominal wall?
The falciform ligament
What pouch is formed by the peritoneum in the male?
The rectovesicle pouch
What pouches are formed by the peritoneum in the female?
The rectouterine pouch
The uterovesicle pouch
What levels do sympathetic nerves that supply the abdominal organs leave the spinal cord at?
T5-L2
Do the sympathetic nerves that supply the abdominal organs synapse in the sympathetic chains?
No, but they pass through them.
Which nerves do the sympathetic nerves supplying the abdominal organs leave the sympathetic chain within?
Abdominopelvic splanchnic nerves
Where do sympathetic nerves supplying abdominal organs synapse ?
At prevertebral ganglia which are located anterior to the
aorta at the exit points of the major branches of the
abdominal aorta
Describe the route taken by postsynaptic sympathetic nerve fibres which supply abdominal organs
Postsynaptic sympathetic nerve fibres pass from the prevertebral ganglia (celiac, superior mesenteric etc) onto the surface of the arterial branches leaving the abdominal aorta
• They take part in “periarterial plexuses”
(around the arteries) with other nerve fibres
(parasympathetic and visceral afferent) as they
“hitch a ride” with the arteries, and their branches, towards (or away from if sensory) the smooth muscle
and glands of the organs
Describe the nerve supply to the adrenal glands
The nerve supply to the adrenal glands is unique.
Sympathetic nerve fibres destined for the adrenal gland
leave the spinal cord (approx. T10-L1) and enter the
abdominopelvic splanchnic nerves, do not synapse at the
prevertebral ganglia, and are carried within periarterial
plexuses to the adrenal gland where they “synapse” directly onto cells.
How does the vagus nerve supply abdominal organs?
presynaptic parasympathetic nerve fibres within the vagus nerves enter the abdominal cavity on the surface of the oesophagus (“vagal trunks”)
• travel towards and into the periarterial plexuses around the abdominal aorta
• carried to the walls of the organs where they synapse in ganglia
• supply parasympathetic nerve fibres to the GI tract + abdominal organs up to the distal end of the transverse colon
What are the pelvic splanchnic nerves?
S 2, 3, 4
What do the presynpatic parasympathetic nerve fibres in the splanchnic nerves innervate?
the smooth muscle/glands of the descending colon to anal canal
Where does pain from a) the foregut structures, b) the midgut structures and c) the hindgut structures tend to be felt?
a) the Epigastric region
b) The umbilical region
c) the pubic region
What do pain fibres from the vast majority of the
abdominal organs run alongside?
Sympathetic fibres back to the spinal cord
Where do pain fibres from the foregut structures enter the
spinal cord?
Approx. T6 - T9
Where do pain fibres from midgut structures enter the
spinal cord?
Approx T8-T12
Where do pain fibres from hindgut structures enter the
spinal cord?
Approx T10- L2
Where does pain from the abdominal organs tend to be felt by the patient?
in the dermatomes of the levels at which they enter the spinal cord, (there is a little overlap)
this can be considered a type of “referred pain”
What are the somatic motor, somatic sensory and sympathetic nerve fibres supplying the structures (including the muscles) of the abdominal part of the “body wall” conveyed within?
the thoracoabdominal nerves
The subcostal nerve (T12 anterior ramus)
The iliohypogastric nerve (Half of L1 anterior ramus)
The ilioinguinal nerve (the other half of L1 anterior ramus)
Where are the the thoracoabdominal nerves derived from?
the 7th to the 11th intercostal nerves travel anteriorly then their terminal branches leave the intercostal spaces, inthe plane between the internal oblique & the transversus abdominus, as the thoracoabdominal nerves
