CVS anatomy- anatomy of chest pain Flashcards
How does the autonomic innervation of the heart reach the heart?
Via the cardiac plexus
Where do visceral afferent fibres from the heart go?
Pain fibres travel to the spinal cord alongside sympathetic fibres
Visceral reflex afferents (e.g. from baroreceptors) travel mainly in the vagus nerve (some in CN IX)
What are the different cervical sympathetic ganglia?
Superior, middle and inferior
At which level of the spinal cord do the sympathetic fibres leave?
T1- L2/3 (thoracolumbar)
What are the sympathetic nerves to the heart and lungs transmitted in?
The cardiopulmonary splanchnic nerves
Is sympathetic innervation of the heart unilateral or bilateral?
Bilateral (but predominantly left sided)
How do sympathetic signals from the CNS reach the heart?
They travel inferiorly within spinal cord tracts
They exit the spinal cord in one of the T1- 5 spinal nerves (thoracolumbar nerves), then they travel superiorly in the sympathetic chain and synapse at another ganglion.
The post synaptic fibres are transmitted to the heart in the cardiopulmonary splanchnic nerves (post synaptic fibres from the cervical and upper thoracic sympathetic chains)
What does the cardiac plexus contain?
Sympathetic nerves
Parasympathetic nerves
Visceral afferents
How do parasympathetic signals reach the heart?
In cranial nerve X (the vagus nerve)
It carries presynaptic fibres which synapse in the walls of the heart.
Which nerve fibres to/from the heart travel in the cardiopulmonary splanchnic nerves?
Post synaptic cardiac sympathetic efferent
Visceral afferent
Where do action potentials from body sensation arrive in the brain?
What are these signals called?
The postcenetral gyrus of the parietal lobe
Somatosensory
Where do action potentials that cause a conscious skeletal muscle contraction originate from in the brain?
What are these signals called?
The precentral gyrus of the frontal lobe
Somatomotor
Describe how the pain in shingles (herpes zoster) comes about
Reactivation of dormant virus in posterior root ganglion
• Pain can be felt anywhere in that dermatome
• Pain precedes blisters
• Patient with shingles developing in T4/T5 dermatome may present with central chest pain
Where does the left phrenic nerve pass in relation to the lung hilum?
Anterior to it
What is the remnant of the ductus arteriosus connecting the pulmonary trunk to the aorta?
Ligamentum artereosum
What is radiating pain?
The PAIN is felt BOTH at the actual site of the pathology AND ALSO radiating (spreading away from there)
Where does pain radiate to from a somatic structure?
Along the affected dermatome
Where does pain from the heart radiate to?
the dermatomes supplied by the spinal cord levels at which the cardiac visceral afferents enter the sympathetic chain/spinal cord i.e. BILATERALLY to cervical and upper thoracic dermatomes.
Describe visceral radiating pain
it is “visceral” in nature i.e. although it is felt in a dermatomal pattern, it is still dull, aching and poorly localised in nature
What is referred pain?
the sensation of pain is “felt” ONLY at a site remote from the actual area of injury or disease
• Otherwise very similar principle to radiating pain
What causes referred pain?
Due to afferent (sensory) fibres from soma and afferent
(sensory) fibres from viscera (visceral afferents) entering
the spinal cord at the same levels
• The brain chooses to believe that the pain signals coming from the organ, are actually coming from the
soma
Describe cardiac referred pain
in CARDIAC referred pain the brain chooses to believethe pain signals are coming from the upper limbs (especially the left upper limb) or from the back, neck (or jaw).
What is a right dominant pattern of coronary artery supply?
When the posterior interventricular artery is a branch of the right coronary artery
What is left dominant pattern of coronary artery supply?
When the posterior interventricular artery is a branch of the left coronary artery
