Anatomy Flashcards
How is the location of the phrenic nerve different to the vagus nerve near the heart
The phrenic nerve is anterior to the lung hilum while the vagus nerve is posterior to the lung hilum
Layers of the pericardium from outside to inside (5)
Fibrous pericardium - For protection Parietal Serous pericardium Pericardial cavity Visceral Serous pericardium Epicardium - Secretes fluid lubricant and makes anterior surface of heart
Cardiac tamponade
When the pericardial cavity fills with blood (haemopericardium) causing the pressure to increase and prevent cardiac contraction
Pericardiocentasis (2)
Drainage of fluid from the pericardial cavity
Done via needle inserted at infrasternal angle and directed superoposteriorly, aspirating continuously
Heart surfaces (3)
Anterior (sternocostal) surface
Base (posterior) surface
Inferior (diaphragmatic) surface
Heart borders (4)
Right (lateral) border
Left (lateral) border
Inferior border
Superior border
Location to palpate apex beat of the heart and indication (2)
Left 5th intercostal space in the midclavicular line
Cardiac enlargement often moves beat to the left
Which structure separates the base border from the diaphragmatic border
The coronary sinus in the atrioventricular groove posteriorly
Coronary arteries function and implication
Arterial blood supply to epicardium and myocardium
Blockage results in myocardial infarction
Where do the coronary arteries arise from
Ascending aorta
What is the coronary sinus
A short venous conduit which receives deoxygenated blood from most of the cardiac veins and drains into the right atrium
Septum and its parts (3)
Divides the heart into right and left
Interatrial septum - Part of septum between the 2 atria
Interventricular septum - Part of the septum between the 2 ventricles
Septal defect types and implications (3)
Atrial septal defect - Hole in the interatrial septum
ventricular septal defect - Hole in the interventricular septum
Allows mixing of arterial and venous blood in the heart causing hypoxaemia due to a decrease in oxygen content of systemic arterial blood in the aorta
Role of papillary muscles and tendinous cords
Prevents prolapse of the tricuspid and mitral valves during ventricular contraction
Function of moderator band (septomarginal trabecula)
Carries fibres of right bundle branch to the 3 papillary muscles of the anterior cusp to ensure uniform contraction
Presynaptic sympathetic fibres from the brain (2)
Travel inferiorly within spinal cord tracts
Then exit the spinal cord in one of T1-L2/3 spinal nerves (thoracolumbar)
Fates presynaptic sympathetic fibres (5)
Go into the ganglion of that level and synapse
Travel superiorly in the sympathetic chain to another ganglion and synapse
Travel inferiorly in the sympathetic chain to another ganglion and synapse
Pass straight through the sympathetic chain ganglion without synapsing, as abdominopelvic splanchnic nerves ,to synapse in one of the prevertebral ganglia of the abdomen
Pass straight to the adrenal medulla without synapsing as an abdominopelvic splanchnic nerve
How do postsynaptic sympathetic fibres reach the heart and lungs(2)
By cardiopulmonary splanchnic nerves
In a midline organ there will be bilateral sympathetic innervation
Cardiopulmonary splanchnic nerves location
Postsynaptic fibres from cervical and upper thoracic sympathetic chains
The cardiac plexus contains (3)
Sympathetic fibres
Parasympathetic fibres
Visceral afferent fibres
Where are the parasympathetic ganglion synapse located
On the surface of organs
Vagus nerve function in the heart
Supplies presynaptic parasympathetic fibres onto postsynaptic neurones on the surface of the heart
Somatic chest pain origins and description
Muscular, joint, bony, nerve, pericardial, intervertebral disc
Nature is sharp, stabbing and well localized
Visceral chest pain origins and description
Heart, great vessels, trachea, oesophagus, abdominal viscerae (gastritis, pancreatitis, hepatitis)
Nature is dull, aching, nauseating and poorly localized
How is pain generated in chest
Skin mechanoreceptors propagates AP stimulated in anterior ramus and travels centrally to spinal cord where pain pathway crosses to brain
Precentral gyrus of frontal lobe function
APs originating here bring about contractions of somatic skeletal muscle
Postcentral gyrus of parietal lobe function
APs arriving here bring somatic sensations into “consciousness”
Sensory homunculus
Indicates pain regions of the cerebral neocortex where sensation from various body structures reaches consciousness
Vagus nerve location (2)
Posterior to hilum of the lung
Anterior to the aortic arch
How do pain signals from the heart reach the brain (2)
Cardiopulmonary splanchnic nerves contain visceral afferents
Visceral afferent APs pass bilaterally to thalamus and hypothalamus then diffuse into cortex
Radiating pain of the heart
If from the heart the radiation is to the dermatomes supplied by the spinal cord levels at which the cardiac visceral afferents enter the sympathetic chain/spinal cord - Bilaterally to cervical and upper thoracic dermatomes
Referred pain of the heart (3)
Pain is felt at site remote to place of injury
This is due to to afferent (sensory) fibres from soma and from viscera (visceral afferents) entering the spinal cord at the same levels
The brain believes that the pain signals coming from the organ are actually coming from the soma
Types of MI (3)
Anterior MI
Inferior MI
Anterolateral MI
Coronary Atherosclerosis common sites (Most to least) (4)
Anterior interventricular branch - 40 to 50%
Right coronary artery - 30 to 40%
Circumflex branch of LCA - 15 to 20%
Left (main stem) coronary artery
Coronary Artery Bypass Grafting (CABG)
Grafts from radial artery, internal thoracic artery and great saphenous vein are anastomosed to coronary arteries proximal to ascending aorta
Blood supply to conducting system of the heart (2)
SAN branch from right coronary artery near its origin
AVN branch from right coronary artery near origin of posterior interventricular artery
Blood supply of interventricular septum (2)
Anterior interventricular artery
Posterior interventricular artery
Transverse thoracic plane located
Between sternal angle and T4/T5 intervertebral disc
Thoracic inlet location
Bounded by ribs 1, T1 vertebra and jugular notch
Anterior mediastinum features (2)
Between sternum and fibrous pericardium
In childhood it is location of thymus gland
Middle mediastinum contains (3)
Pericardium
Heart
Great vessels
Posterior mediastinum contains (8)
Vagus nerves Trachea and main bronchi Thoracic aorta Oesophagus Vagal trunks Thoracic duct Sympathetic chains Azygous vein
Azygous vein function
Drains venous blood of each intercoastal space to SVC
Aorta parts (4)
Ascending
Arch
Thoracic
Abdominal/ descending
Branches of the aorta (first to last) (4)
Coronary arteries
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
Branches from thoracic aorta anterior surface (5)
Bronchial Oesophageal Mediastinal Pericardial Pherenic
Aortic hiatus function
Opening in diaphragm for abdominal aorta
What drain drains lymph into right venous angle
Right lymphatic duct
What drains lymph into left venous angle
Thoracic duct
Cisterna Chyli
Swollen start of thoracic duct in abdomen
Left venous angle location
Between subclavian vein and internal jugular vein
Ligamentum arteriosum (2)
Remnant of ductus arteriosus
Located between laryngeal branch of left vagus nerve and phernic nerve
Superior mediastinum components (Anterior to posterior) (5)
Brachiocephalic veins & SVC Arch of aorta Trachea Oesophagus Thoracic duct
Superior mediastinum components (lateral to medial) (3)
Phrenic nerves
Vagus nerves
Recurrent laryngeal nerves
Central veins (7)
Internal jugular veins Subclavian veins Brachiocephalic veins SVC IVC Iliac veins Femoral veins
Right recurrent laryngeal nerve (2)
Hooks under right subclavian artery
DOES NOT enter chest
Left recurrent laryngeal nerve (2)
Hooks under aortic arch
DOES enter chest
Referred pain of diaphragm (3)
Lining of inferior surface is by phrenic nerve C3,4 and 5 Supraclavicular nerves (C3 and 4) supply dermatomes over shoulder tip Brain refers to pain as more superficial structures so pain indicates sensory territory of phrenic nerve
