Anatomy: abdominal pain and likely sources Flashcards
Roughly how long is the small intestine?
7m
What are the names of the three parts of the small intestine?
Duodenum (short), jejunum (around 3m) and ileum (around 4m)
What is the large intestine made up of?
The colon: caecum, appendix, ascending colon, transverse colon, descending colon and sigmoid colon
The rectum, anal canal
and anus
What are the three divisions of the abdominal organs?
Foregut, midgut and hindgut
What abdominal organs are in the foregut?
Oesophagus to mid-duodenum
Liver, gallbladder, spleen and 1/2 pancreas
What abdominal organs are in the midgut?
Mid-duodenum to proximal 2/3rd of transverse colon
1/2 pancreas
What abdominal organs are in the hindgut?
Distal 1/3rd of the transverse colon to proximal 1/2 of the anal canal
What are the 9 regions of the abdominal cavity?
Right & left hypochondrium, epigastric, right & left lumbar, umbilical, right & left inguinal and pubic
Where are the lines that divide the 9 regions?
Mid-clavicular, subcostal and trans-tubercular planes
What are the 4 quadrants of the abdominal cavity?
Right & left upper quadrants
Right & left lower quadrants
Where are the divisions for the 4 quadrants?
Median and trans-umbilical planes
Name the muscles of the anteriolateral abdominal wall
Rectus abdominis, external oblique, internal oblique and transversus abdominis
How do the abdominal muscles guard the abdominal organs when injury threatens?
They contract
also happens in peritonitis
What is the peritoneum?
A thin, transparent, semi-permeable, serous membrane that lines the walls of the abdominopelvic cavity and organs
What is the parietal peritoneum?
Peritoneum that is in contact with the body wall (soma)
What is the visceral peritoneum?
Peritoneum that is in contact with the organs
Explain the nerve supply to the peritoneum
The peritoneum is sensitive as it has a nerve supply
The parietal peritoneum is supplied by the same nerves as the body wall
The visceral peritoneum is supplied by the same nerves as the organs
What is the peritoneal cavity?
Thin, enclosed space between the parietal and visceral layers that contains a small amount of peritoneal fluid
What is peritonitis and what can cause it?
Inflammation of the peritoneum
Cause: blood, pus or faeces in the peritoneal cavity
What are the 3 organ classes that are dependent on their relationship with the peritoneum?
Intraperitoneal, retroperitoneal and with a mesentery
What defines an intraperitoneal organ?
Almost completely covered in visceral peritoneum
Minimally mobile
What organs are intraperitoneal?
The stomach, the first 5 centimeters and the 4th part of the duodenum, jejunum, ileum, caecum, appendix, transverse colon, sigmoid colon, and the upper 1/3 of the rectum, as well as, the liver, spleen, and the tail of the pancreas.
What defines a retroperitoneal organ?
Only has visceral peritoneum on its anterior surface
Located in the retroperitoneum
What organs are retroperitoneal?
Supradrenal glands, ureter, kidney, bladder, aorta, inferior vena cava, part of the oeosphagus and part of the rectum
Pancreas, duodenum (not first part), ascending and descending colon
SAD PUCKER
What defines an organ with a mesentery?
Covered in visceral peritoneum
Visceral peritoneum wraps behind the organ to form a double layer - mesentery
Mesentery suspends the organ from the posterior abdominal wall - very mobile
What are condensations of the peritoneum?
Double layers that attach organs to each other or to the abdominal wall
They are secondary to growth and rotation of the GI tract during embryology
Name 4 condensations of the peritoneum
Falciform ligament
Greater and lesser omentum
Mesentery of small intestine
How do the two sacs of the peritoneal cavity, the lesser and greater sac, communicate?
Omental foramen
Where does the portal triad lie?
In the free edge of the lesser omentum
There are pertioneal pouches formed due to the peritoneum draping over the superior aspect of the pelvic organs. How many pouches do males and females have?
One pouch in males
Two pouches in females
What is the name of the male peritoneal pouch?
Rectovesical
What are the names of the peritoneal pouches in females?
Uterovesical
Rectouterine (Pouch of Douglas)
What is the name for excess fluid in the peritoneal cavity?
Ascitic fluid
What is the condition called when a patient has excess fluid in the peritoneal cavity?
Ascites
What is the name of the procedure where ascitic fluid is drained from the peritoneal cavity?
Paracentesis
Where should the needle be placed during paracentesis?
Lateral to the rectus sheath to avoid the inferior epigastric artery
What artery does the epigastric artery arise from?
External iliac
Is visceral or somatic pain harder to localise?
Visceral
What is the characteristic of visceral pain?
Dull, achy and nauseating
What is the characteristic of somatic pain?
Sharp and stabbing
What is Colicky pain and what GI problem may it indicate?
Pain that comes in waves, it usually starts and ens suddenly and is often severe
(Peristalsis comes in waves so it may indicate a GI obstruction
What is the nerve supply to the organs and visceral peritoneum?
Visceral afferents (sensory nerves) Enteric nervous system
What is the effect of the autonomic motor nerve supply of the enteric nervous system?
Parasympathetic - speeds up peristalsis
Sympathetic - slows down peristalsis
What is the nerve supply to the skin through to the parietal peritoneum?
Somatic sensory, somatic motor and sympathetic nerve fibres
How do sympathetic nerve fibres get from the CNS to the abdominal organs?
Leave the spinal cord between levels T5 and L2
Enter the sympathetic chains but do not synapse
Leave the sympathetic chains within abdominopelvic splanchic nerves
Synapse at prevertebral ganglia
Postsynaptic sympathetic nerve fibres pass from the prevertebral ganglia
Where are the prevertebral ganglia located?
Anterior to the aorta at the exit points of the major branches of the abdominal aorta
What do the postsynaptic sympathetic nerve fibres pass on the surface of?
Arterial branches leaving the abdominal aorta
What do the nerve fibres form around the arteries?
Periarterial plexuses
The adrenal gland is unique. Where do the sympathetic nerve fibres for the adrenal gland leave the spinal cord?
T10-L1
Where do the fibres supplying the adrenal gland synapse?
Directly onto cell (NOT at prevertebral ganglia)
How does the vagus nerve (parasympathetic) get from the CNS to the abdominal organs?
Presynpatic parasympathetic nerve fibres enter abdominal cavity on the surface of the oeosphagus
Travel into the periarterial plexuses
Carried to organ walls where they synpase in ganglia
What does the vagus nerve supply?
Parasympathetic fibres to the GI tract and abdominal organs up to the distal end of the transverse colon
What do the pelvic splanchnic nerves (S2, 3 and 4) supply?
Smooth muscle/glands of the descending colon to anal canal
Where does pain from the foregut tend to be felt?
Epigastric region
Where does pain from the midgut tend to be felt?
Umbilical region
Where does pain from the hindgut tend to be felt?
Pubic region
Where do most visceral fibres from the abdominal organs to the CNS run?
Alongside sympathetic fibres
Where do the visceral afferents from the foregut structures enter the CNS?
T6-T9
Where do the visceral afferents from the midgut structures enter the CNS?
T8-T12
Where do the visceral afferents from the hindgut structures enter the CNS?
T10-L2
Where is organ pain often perceived by a patient?
Dermatomes of the levels at which they enter the spinal cord - referred pain
Where is the common site for referred pain for the liver or gallbladder?
Right shoulder
Where is the common site for referred pain for the stomach?
Epigastric or between the shoulder blades
Where is the common site for referred pain for the gallbladder?
Right side round to right upper back
Where is the common site for referred pain for the liver?
Right lower front round to right lower back
Where is the common site for referred pain for the small intestine?
Umbilical region
Where is the common site for referred pain for the duodenum and pancreas?
Epigastric and mid back (centre, below shoulder blades)
similar to stomach referred pain
Where is the common site for referred pain for the spleen?
Left side
Where is the common site for referred pain for the kidney and ureter?
Left hip around to left lower back
Where is the common site for referred pain for the appendix?
Umbilical and as condition gets worse it moves to the right
What are the somatic motor, somatic sensory and sympathetic nerve fibres supply the body wall conveyed within?
Thoracoabdominal nerves, subcostal nerve, iliohypogastric nerve and ilioinguinal nerve
What specific thoracoabdominal nerves?
7th - 11th intercostal nerves
What leel is the subcostal nerve?
T12 anterior ramus
What part of the iliohypogastric nerve?
Half of L1 anterior ramus
What part of ilioinguinal nerve?
Other half of L1 anterior ramus
Why does the pain from appendicitis start as a dull, aching pain but become a sharper pain at a point?
It is a midgut organ - pain tends to be felt in the umbilical region (visceral afferents T8-T10)
As appendicitis worsens it starts to irritate the peritoneum in the right iliac fossa - becomes a somatic pain
