Anatomy - Referred pain Flashcards
Describe the arrangement of the enteric nervous system
- Ganglionic plexuses with interconnecting bundles of unmyelinated nerve fibres
- Project to sympathetic ganglia, the pancreas, gall bladder, trachea, spinal cord and brain stem
- From the oesophagus to the anus following the gut wall
What is the function of the enteric nervous system?
- Allows the GI tract to perform its basic reflex functions of secretion, absorption, mixing and gut movements without influence of the CNS
- CNS can modify GI tract functions by communicating with the ENS
Compare the function of the myenteric plexus and the submucosal plexus
- Submucosal plexus causes the muscularis mucosae to contract (making folds in the stomach for example)
- Myenteric plexus causes peristalsis/ segmentation via the longitudinal and circular muscle
What are the functions of the autonomic efferent nerves in the abdomen?
- Motor to smooth muscle
- Secretomotor to glands
What are the functions of the autonomic afferent nerves in the abdomen?
- Sympathetic responds to pain
- Parasympathetic response to functional sensation, such as stretch
Where does the greater splanchnic nerve arise adn where does it go?
- T5-9
- Celiac ganglion
Where does the lesser splanchnic nerve arise, and where does it go?
- T10-11
- Aorticorenal ganglion
Where does the least splanchnic nerve arise and where does it go?
- T12
- Renal pelvis
What are the two types of splanchnic nerves?
- Thoracic, lumbar and sacral nerves from sympathetic trunk to ganglia in the prevertebral plexus
- Pelvic splanchnic nerves are parasympathetic (S2-4) from prevertebral plexus (directly from S2-S4) to pelvis
How many lumbar splanchnic nerves are there?
Two to four, pass from the lumbar part of the sympathetic trunk to the prevertebral plexus
What is innervated by the pelvic splanchnic nerves?
- Fibres pass upward to enter the abdominal prevertebral plexus and distribute with the arteries supplying the hindgut
- Provides the pathway for innervation of the distal 1/3rd of the transverse colon, descending colon and sigmoid colon
What are the three main abdominal prevertebral plexus divisions?
- Present in the abdominal prevertebral plexus, scattered through the length of the abdominal prevertebral plexus
- Celiac plexus
- Aortic plexus
- Superior hypogastric plexus
Describe the position and ganglia of the celiac plexus
- Associated with roots of the celiac trunk and the superior mesenteric artery.
- Two celiac ganglia
- A superior mesenteric ganglia
- Two aorticorenal ganglia
Describe the position and ganglia of the aortic plexus
- Just below the superior mesenteric artery
- Major ganglion is the inferior mesenteric ganglion
Describe the position and ganglia of the superior hypogastric plexus
- Numerous small ganglia
- Final part of the prevertebral plexus
What does the abdominal prevertebral plexus receive?
- Preganglionic parasympathetic and visceral afferent fibers from the vagus nerves [X]
- Preganglionic sympathetic and visceral afferent fibers from the thoracic and lumbar splanchnic nerves
- Preganglionic parasympathetic fibers from the pelvic splanchnic nerves.
What do the vagus nerves innervate in the abdomen?
- Foregut and midgut
- Anterior (left) and posterior (right) vagal trunks
How do sympathetic nerves in the abdomen run?
- With somatic nerves of the same region
- To organs they run with the arteries to the same organ
Why does referred pain occur?
- The cerebral cortex has no sensory map for visceral organs and the diaphragm
- Brain cannot localise sensation, so the pain is reffered to the skin supplied by nerves with the same segmental supply (dermatomes)
Which spinal level has no dermatome?
C1
Pain from which organs cause pain in the epigastric region?
- Foregut structures
- Stomach
- Proximal duodenum
- Pancreas
- Liver
- Gall bladder
Pain from which organs cause pain in the umbilical region?
- Pain from midgut structures
- Appendix causes a colicky pain (intermittent with bowel contractions)
Describe the progression of pain in appendicitis
Pain becomes localized and constant at the right inguinal region when inflammation of the appendix spreads to surrounding peritoneum
Pain from which organs cause pain in the suprapubic region?
- Hidgut organs
- Descending colon to anal canal
What nerves supply the epigastric region?
T7/8
What nerves supply the umbilical region?
T10
What nerves supply the inguinal region?
T12/L1
What nerves supply the suprapubic region?
T12/L1-2
List the pre-aortic lymph nodes
- Celiac nodes (by the celiac trunk, drains the abdominal foregut as well as recieving lymph from superior/inferior mesenteric nodes to drain into the cisterna chyli)
- Superior mesenteric nodes (recieves from inferior drains into celiac, main function to drain the midgut)
- Inferior mesenteric nodes (drains the hind gut)
