Anatomy Flashcards
Sinus of Valsalva
The dilated portion of the aorta which faces the valve leaf
Mitral Valve Leaflets
Two
Anterior and Posterior
Which surface of the heart does the left phrenic nerve pass over?
The pericardium of the left ventricle, along the lateral border
What is the innermost layer of the pericardium?
Epicardium (i.e. visceral pericardium)
How much fluid would usually be found within the pericardium?
50 ml of clear, straw-coloured fluid
Intra-Pericrdial Pressure
Usually either negative or zero
Cardiac Tamponade
Result of increased pericardial pressure
Prevents heart contraction
Name the condition in which the pericardial cavity feels with blood?
Haemopericardium
Where is the needle inserted or pericardiocentesis?
Via infrasternal angle, and directed superoposteriorly, aspirating continuously
Where does the Transverse Pericardial Sinus lie?
Posterior to the ascending aorta and pulmonary trunk
What is the fibrous pericardium?
The tough external layer lined with serous pericardium
What is the parietal serous pericardium?
In contact with the fibrous pericardium
Reflects onto the heart at the great vessels, becoming the visceral serous pericardium
What is the visceral serous pericardium?
In contact with the heart
AKA, epicardium
Secretes pericardial fluid lubricant
What is the pericardial cavity?
Potential space between the two layers of serous pericardium
Normally contains a thin layer of fluid
What is the purpose of the fluid in the pericardial cavity?
Enables the heart to move and beat in a frictionless environment
What are the three clinically important surfaces of the heart and which areas of the heart are they mainly formed by?
Anterior (sternocostal) = right ventricle
Base (posterior) = left atrium
Inferior (diaphragmatic) = mostly left ventricle, partly right
What are the heart borders and which areas of the heart are they formed by?
Right border = right atrium
Left (lateral ) border = left ventricle, some of left atrium
Where is the apex usually located?
5th intercostal space, midclavicular line
What covers the great vessels of the heart?
Proximal part = pericardium
Distal parts = adventitia
What is the coronary groove a surface marking for, and what vessel sits in it?
Tricuspid valve
Right coronary artery
What is the anterior interventricular groove a surface marking for, and what vessel sits in it?
The boundary between the two ventricles (interventrciular septum)
LAD/anterior interventricular artery
Which arteries arise from the ascending aorta?
Right and left coronary arteries
Which arteries branch of the arch of the aorta?
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
What does the brachiocephalic trunk branch into?
Right common carotid artery
Right subclavian artery
What is the posterior interventricular groove a surface marking for, and which vessel sits in it?
The boundary between the two ventricles (interventricular septum) on the diaphragmatic side
Posterior interventricular artery (and vein)
What is the intertribal groove a surface marking for?
The boundary between the atria
What is the coronary sinus, what is its function and where does it sit?
A short venous conduit
receives deoxygenated blood from most of the cardiac veins, and drains into the right atrium
Sits in the posterior atrioventricular groove
How many pulmonary veins are there?
Two right
Two left
Where do the coronary arteries sit in the layers of the heart?
Just deep to the epicardium, usually embedded in adipose tissue
Which vessels come off of the right coronary artery?
Right marginal artery
Posterior interventricular artery
What are the branches of the left coronary artery, and which vessels come off from these?
Circumflex artery = Left marginal artery
LAD/anterior interventricular artery = left (diagonal) branch
What is the septum?
An internal wall of the heart, dividing it into a left and right side
What are the two parts of the septum?
Interatrial septum = Between the atria
interventricular septum = Between the two ventricles
What two kinds of septa defects can occur?
Atrial septal defect
Ventricular septal defect
What life threatening problem can occur as a result of a sept defect
Mixing of arterial and venous blood in the heart
This reduces the oxygen content of systemic arterial blood in the aorta (hypoxaemia)
Which vessels open into the right atrium?
SVC
IVC
Coronary Sinus
What lines the right atrium?
Crista terminalis (a vertical ridge)
What is the oval fossa and where would you find it?
Embryological remnant of a foramen which connected the two atria
Right atrium
Remnants of the valve may be seen in the left atrium
What are the openings in the left atrium for?
Bilateral drainage of the superior and inferior pulmonary veins
Where is the tricuspid valve located?
Between right atrium and ventricle
What is the anatomy of the tricuspid valve?
Anterior, posterior and septal cusps
Cusps connected to tendinous cord, which are attached to the walls of the right ventricle via papillary muscles
in an oblique section of the heart, it is associated with the right posterior fibrous ring
Where is the pulmonary valve located?
Between the right ventricle and pulmonary artery
What is the anatomy of the pulmonary valve?
Anterior, right and left cusps
In an oblique section of the heart, it is associated to the most posterior fibrous ring
Where is the mitral valve located?
Between the left atrium and ventricle
What is the anatomy of the mitral valve?
Anterior and posterior cusps
Cusps connected to tendinous cords, which are attached to the walls of the left ventricle via papillary muscles
In an oblique section of the heart, it is associated with the left anterior fibrous ring
Where is the aortic valve located?
Between the left ventricle and aorta
What is the anatomy of the aortic valve?
Posterior, right and left cusps with sinuses (spaces) in between
In an oblique section of the heart, it is associated to the middle most fibrous ring
Where would you find the moderator band of the tricuspid valve, and what is its function?
Right ventricle
Carries fibres of the right bundle branch to the papillary muscle of the anterior cusp
What are the walls of the left ventricle like?
2-3x thicker than those of the right ventricle
What are the papillary muscles in the left ventricle like?
Bigger than those in the right
What two types of nervous innervation exist in the heart?
Autonomic - sympathetic and parasympathetic
Viceral Afferents - Pain fibres and visceral reflex afferents
How do sympathetics get from CNS to the organs?
CNS -> Presynaptic fibre -(acetylcholine)-> Sympathetic chain ganglion -> Postsynaptic fibre -(noradrenaline)-> Heart
Where do the presynpatic sympathetic fibres leave the spinal cord on their way to the heart?
In one of T1-L2/3 spinal nerves
What do the presynpatic sympathetic fibres do once they have left the spinal cord?
1 - Go into the ganglion of that level and synapse
2 - Travel superiorly in the sympathetic chain to another ganglion and synapse
3 - Travel inferiorly in the sympathetic chain to another ganglion and synapse
How do postsynaptic sympathetic fibres reach the heart?
Via the cardiopulmonary splanchnic nerves (T1-T5 and cervical ganglia)
There is bilateral sympathetic innervation of the heart
Which nerve fibres are contained within the cardiac plexus?
Sympathetic
Parasympathetic
Visceral afferents
How do parasympathetics get from the CNS to the organs?
CNS -> Presynaptic fibre -(acetylcholine)-> Parasympathetic ganglion -> Postsynaptic fibre -(acetylcholine)-> Organ
Where do the presynpatic parasympathetic fibres leave the brain on their way to the heart?
CNX (vagus nerve)
What do the presynpatic parasympathetic fibres do once they have left the brain?
Travel with vagus nerve
Synapse onto postsynaptic neurones
These have very short axons as ganglia are located within the heart walls
What do the cardiac visceral afferent nerves travel in?
Cardiopulmonary splanchnic nerves (alongside sympathetic nerves)
What do the visceral reflex afferents travel in?
CNX (vagus nerve)
Where are visceral afferent nerve ending located within the heart?
Inner aortic arch Pulmonary trunk Around the SA node Outflow tracks from both ventricles Papillary muscles Vena Cava
Where re chemoreceptor nerve endings located within the heart?
Root of the aorta
IV septum
What is pain?
Stimulation of sensory receptor
Afferent AP reaches the brain
Nature of somatic chest pain
Sharp, stabbing, well localised
Nature of visceral chest pain
Dull, aching, nauseating, poorly localised
What is radiating pain?
Pain felt in centre of chest and spreading elsewhere
What is referred pain?
Pain only felt at a site remote from the area of tissue damage in the chest
What is the pain pathway for somatic central chest pain to the brain?
Skin mechanoreceptors stimulated in T5 dermatome
AP propagated centrally
Passes through anterior ramus, T5 spinal nerve, T5 posterior roots/rootlets
Crosses the spinal cord
Sensation reaches consciousness at cerebral cortex
In which part of the brain are somatic sensory APs brought to consciousness?
Postcentral gyrus of parietal lobe
Specific causes of somatic central chest pain
Herpes Zoster (shingles) deevloping in T4/5 dermatome
Pectoralis major or intercostal muscle strain
Dislocated costochondral joint
Costovertebral joint inflammation
Slipped thoracic intervertebral disc
Pleurisy
Pericarditis
Specific causes of visceral central chest pain
Angina MI Ruptured aneurysm of aortic arch Oesophagitis Tracheitis Gastritis, cholecystitis, pancreatitis, hepatitis etc.
Where does somatic pain radiate to?
Along the affected dermatome
Where does visceral pain radiate to?
The dermatomes supplied by the spinal cord levels at which the cardiac vessel afferents enter the sympathetic chain/spinal cord
i.e. Bilaterally to cervical and upper thoracic dermatomes
How does referred pain work?
When afferent fibres from the soma and viscera enter the spinal cord at the same level, the brain chooses to believe that the pain signals coming from the organ are actually coming from the soma
Where does cardiac pain refer to?
Upper limbs (especially left upper limb)
Back
Neck
Jaw
Which blood vessels supply the SA node?
SA nodal branch from right coronary artery near its origin (~60% of patients)
AV nodal branch from right coronary artery near the origin of the posterior interventricular artery (~80% of patients)
Ischaemia of coronary arteries leading to AV node damage causes
Complete heart block
Ischaemia of the coronary arteries leading to bundle branch damage causes
Bundle branch block
What is the most common pattern of occlusion in MIs?
Right dominant pattern
What is the arterial blood supply of the interventicular septum?
Posterior interventicular artery
Anterior interventricular artery
Which branches come off the thoracic aorta’s anterior surface?
Bronchial arteries Oesophageal arteries Mediastinal arteries Pericardial arteries Phrenic arteries
What is the function of the azygous vein?
Drains posterior intercostal veins into the SVC
Which branches come off the thoracic aorta bilaterally?
Posterior intercostal arteries (one for each intercostal space)
Where does the vagus nerve sit in relation to the root of the lung?
Posterior
Where does the phrenic nerve sit in relation to the root of the lung?
Anterior
Which structure does the right recurrent laryngeal nerve look under?
Right subclavian artery
Does NOT enter the chest
Which structure does the left recurrent laryngeal nerve hook under?
Arch of the aorta
DOES enter the chest
Which spinal nerves make up the phrenic nerves?
Anterior rami of cervical spinal nerves 3,4 and 5
3,4 and 5 keep the diaphragm alive
Where does diaphragmatic pain radiate?
Shoulder tip
What kinds of nerve fibres do the phrenic nerves contain?
Somatic motor to diaphragm
Somatic sensory to mediastinal parietal pleura, fibrous pericardium, diaphragmatic parietal pleura, diaphragmatic parietal peritoneum
What kind of nerve fibres do the vagus nerve contain?
Somatic sensory for palate, laryngopharynx and larynx
Somatic motor nerves for pharynx and larynx
(ONLY UNTIL THE POINT THEY GIVE OFF THE RLNs)
Autonomic parasympathetics for thoracic and abdominal organs
Which nerves branch off of the vagus nerve?
Recurrent laryngeal nerves
Supply pharynx and larynx
Which lymph nodes drain the bifurcation of the trachea?
Tracheobronchial lymph nodes
Where is the carotid pulse palpated?
Anterior to the sternocleidomastoid muscle at level of superior border of thyroid cartilage
Where is the brachial pulse palpated?
Medial to biceps brachii tendon in the cubital fossa
Where is the radial pulse palpated?
Lateral to tension of flexor carpi radialis
Where is the femoral artery palpated?
Inferior ot midpoint of inguinal ligament
Where is the popliteal pulse palpated?
Popliteal fossa (immediately posterior to knee joint)
Where is the posterior tibial pulse felt?
between the posterior border of the medial malleolus and the achilles tendon
Where is the dorsalis pedis pulse palpated?
Medial to tendon of extensor hallicus longus on the dorsum of the foot
Which lymph nodes drain the main bronchus at the lung root?
Bronchopulmonary lymph nodes
Where does the right lymphatic duct drain?
Right venous angle
Where does the thoracic duct drain?
Left venous angle
What causes the double pulsation of the JVP?
Atrial contraction then filling of the right atrium against a closed tricuspid valve conducted in retrograde into the central veins
Which side of the heart would you get arterial access?
To the left side
Which side of the heart would you get central venous access?
To the right side
