Podcast
Questions and Answers
Which valve is also known as the mitral valve?
Which valve is also known as the mitral valve?
What is the location of the bicuspid valve?
What is the location of the bicuspid valve?
What structure does the blood pass through after leaving the left ventricle?
What structure does the blood pass through after leaving the left ventricle?
What are the chordae tendineae attached to?
What are the chordae tendineae attached to?
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What is the location of the aortic vestibule?
What is the location of the aortic vestibule?
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What is the fibrous skeleton of the heart made of?
What is the fibrous skeleton of the heart made of?
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What is the auscultation point for the tricuspid valve?
What is the auscultation point for the tricuspid valve?
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What does the second heart sound (S2) result from?
What does the second heart sound (S2) result from?
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What structures pass through the superior thoracic aperture?
What structures pass through the superior thoracic aperture?
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What bony structures form the posterior boundary of the inferior thoracic aperture?
What bony structures form the posterior boundary of the inferior thoracic aperture?
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What structure divides the mediastinum into a superior and inferior compartment?
What structure divides the mediastinum into a superior and inferior compartment?
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Which of the following is NOT a topographic line used to describe the thoracic wall?
Which of the following is NOT a topographic line used to describe the thoracic wall?
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Which muscle originates on the medial half of the clavicle, sternum, and costal cartilages?
Which muscle originates on the medial half of the clavicle, sternum, and costal cartilages?
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What is the insertion point of the pectoralis major muscle?
What is the insertion point of the pectoralis major muscle?
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Which compartment of the inferior mediastinum contains the heart?
Which compartment of the inferior mediastinum contains the heart?
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What is the name of the bony structure that constitutes the anterior boundary of the superior thoracic aperture?
What is the name of the bony structure that constitutes the anterior boundary of the superior thoracic aperture?
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What condition is characterized by increased blood flow and pressure to the lung, leading to pulmonary hypertension?
What condition is characterized by increased blood flow and pressure to the lung, leading to pulmonary hypertension?
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Which of the following describes the presentation of a patent ductus arteriosus (PDA)?
Which of the following describes the presentation of a patent ductus arteriosus (PDA)?
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What happens to the direction of shunting in the case of patent ductus arteriosus from the neonatal period?
What happens to the direction of shunting in the case of patent ductus arteriosus from the neonatal period?
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Which substance is primarily responsible for maintaining the patency of the ductus arteriosus?
Which substance is primarily responsible for maintaining the patency of the ductus arteriosus?
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What is the most common cyanotic congenital heart defect?
What is the most common cyanotic congenital heart defect?
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Which vein lies in the anterior interventricular groove?
Which vein lies in the anterior interventricular groove?
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What is the function of the Sinuatrial (SA) node?
What is the function of the Sinuatrial (SA) node?
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Which structure can also produce impulses for the heart?
Which structure can also produce impulses for the heart?
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What is the primary role of the Purkinje fibers?
What is the primary role of the Purkinje fibers?
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Which artery supplies the Sinuatrial node?
Which artery supplies the Sinuatrial node?
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Which part of the conduction system receives impulses from the Sinuatrial node?
Which part of the conduction system receives impulses from the Sinuatrial node?
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Which type of stimulation increases heart rate?
Which type of stimulation increases heart rate?
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Where does the Bundle of Hiss originate?
Where does the Bundle of Hiss originate?
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What structure allows for oxygenated blood to bypass the pulmonary circulation in fetal circulation?
What structure allows for oxygenated blood to bypass the pulmonary circulation in fetal circulation?
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Which remnant forms after the closure of the ductus arteriosus?
Which remnant forms after the closure of the ductus arteriosus?
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What condition results from left to right shunting and is more common in females than males?
What condition results from left to right shunting and is more common in females than males?
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What is responsible for the closure of the ductus arteriosus after birth?
What is responsible for the closure of the ductus arteriosus after birth?
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How does deoxygenated blood primarily exit the right atrium in fetal circulation?
How does deoxygenated blood primarily exit the right atrium in fetal circulation?
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What anatomical change allows for the closure of the foramen ovale after birth?
What anatomical change allows for the closure of the foramen ovale after birth?
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In infants, what is one of the signs of ventricular septal defect (VSD)?
In infants, what is one of the signs of ventricular septal defect (VSD)?
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What is a remnant of the umbilical vein after its closure?
What is a remnant of the umbilical vein after its closure?
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Which of the following is NOT a part of the parietal pleura?
Which of the following is NOT a part of the parietal pleura?
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What is the potential space between the parietal and visceral pleura called?
What is the potential space between the parietal and visceral pleura called?
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What is the main function of the pleura?
What is the main function of the pleura?
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What is the name of the dome-shaped portion of the parietal pleura that extends into the neck?
What is the name of the dome-shaped portion of the parietal pleura that extends into the neck?
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Which nerve supplies the central portion of the diaphragmatic pleura and mediastinal pleura?
Which nerve supplies the central portion of the diaphragmatic pleura and mediastinal pleura?
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What is the condition characterized by a reduction in the number of lung cells, airways, and alveoli?
What is the condition characterized by a reduction in the number of lung cells, airways, and alveoli?
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What is the visceral pleura supplied by?
What is the visceral pleura supplied by?
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Which of the following statements is TRUE regarding the visceral pleura?
Which of the following statements is TRUE regarding the visceral pleura?
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Flashcards
Main bronchi
Main bronchi
The primary passageways that branch from the trachea into the lungs.
Lobar bronchi
Lobar bronchi
The bronchi that branch from the main bronchi into each lobe of the lungs.
Segmental bronchi
Segmental bronchi
The tertiary bronchi that further divide into bronchopulmonary segments.
Ductus venosus
Ductus venosus
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Foramen ovale
Foramen ovale
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Ductus arteriosus
Ductus arteriosus
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Atrial septal defect
Atrial septal defect
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Ventricular septal defect
Ventricular septal defect
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Eisenmenger complex
Eisenmenger complex
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Patent ductus arteriosus (PDA)
Patent ductus arteriosus (PDA)
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Left-to-right shunting
Left-to-right shunting
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Machine-like murmur
Machine-like murmur
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Tetralogy of Fallot
Tetralogy of Fallot
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Great cardiac vein
Great cardiac vein
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Middle cardiac vein
Middle cardiac vein
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Sinuatrial node
Sinuatrial node
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Atrioventricular node
Atrioventricular node
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Bundle of Hiss
Bundle of Hiss
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Purkinje fibers
Purkinje fibers
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Cardiac plexus
Cardiac plexus
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Sympathetic stimulation
Sympathetic stimulation
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Superior Thoracic Aperture
Superior Thoracic Aperture
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Inferior Thoracic Aperture
Inferior Thoracic Aperture
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Mediastinum
Mediastinum
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Superior Mediastinum
Superior Mediastinum
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Inferior Mediastinum
Inferior Mediastinum
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Thoracic Walls
Thoracic Walls
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Pectoralis Major
Pectoralis Major
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Topographic Lines
Topographic Lines
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Pulmonary hypoplasia
Pulmonary hypoplasia
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Parietal pleura
Parietal pleura
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Visceral pleura
Visceral pleura
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Pleural cavity
Pleural cavity
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Costal parietal pleura
Costal parietal pleura
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Mediastinal parietal pleura
Mediastinal parietal pleura
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Innervation of parietal pleura
Innervation of parietal pleura
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Visceral sensory nerves
Visceral sensory nerves
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Bicuspid valve
Bicuspid valve
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Trabeculae carneae
Trabeculae carneae
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Papillary muscles
Papillary muscles
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Chordae tendineae
Chordae tendineae
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Aortic vestibule
Aortic vestibule
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Heart sounds
Heart sounds
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Auscultation points
Auscultation points
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Heart murmurs
Heart murmurs
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Study Notes
Thorax
- Netter's clinical Anatomy 2nd ed. is a resource for clinical anatomy.
- Clinically oriented anatomy 6th ed. is another reference.
- Prometheus atlas of anatomy is a resource, as well.
- Gray's Anatomy for students is a textbook.
- Sobotta Atlas of human anatomy is another resource.
Skeleton of back and thorax
- Superior thoracic aperture is the base of the neck.
- It's posteriorly bordered by the body of T1 vertebra.
- It's laterally bordered by the first pair of ribs.
- It's anteriorly bordered by the superior border of the manubrium.
- Structures passing through the aperture include large vessels, nerves, thoracic lymphatic duct, trachea, and esophagus.
- Inferior thoracic aperture is closed by the diaphragm.
- Posteriorly bordered by the body of T12
- Posterolaterally bordered by the 11th and 12th ribs
- Anterolaterally bordered by the costal cartilages of ribs 7-10.
- Anteriorly bordered by the xiphisternal joint.
- Structures passing through the aperture include the inferior vena cava, aorta, esophagus, thoracic lymphatic duct.
Mediastinum
- Thorax contains two pleural cavities laterally and a central middle space called the mediastinum.
- Superior mediastinum is above a horizontal plane that passes through the manubrium.
- Inferior mediastinum is below that plane, and further subdivided into an anterior, middle (containing the heart), and posterior mediastinum.
Thoracic walls
- Topographic lines help define anatomical regions on the thoracic walls.
- Muscles of the thorax include the pectoralis major, which originates from the medial half of the clavicle, sternum, and costal cartilages.
- It inserts on the lateral lip of the intertubercular groove of the humerus.
- Its actions include adduction, flexion, and medial rotation of the arm, in addition to rib elevation (inspiration).
- The subclavius muscle originates from the inferior surface of the clavicle shaft and inserts onto the first rib.
- Its action is to pull the shoulder tip inferiorly.
- The serratus anterior muscles originate from the lateral parts of ribs 1-9 and inserts onto the medial border of the scapula.
- Actions include scapula rotation, protraction, scapula elevation against the thoracic wall, and rib elevation.
- The levatores costarum muscles are 12 fan-shaped muscles that elevate the ribs.
- Intercostal muscles (external and internal) contribute to rib elevation during inspiration.
- Subcostal muscles depress ribs during expiration.
- Transverse thoracic muscles also depress ribs during expiration.
Diaphragm
- The diaphragm is a flat muscle separating thoracic and abdominal cavities.
- It's attached to the xiphoid process, costal cartilages, and lumbar vertebrae.
- Fibers converge to the central tendon.
- The diaphragm's median sagittal plane slopes inferiorly from the xiphoid attachment to the diaphragm at vertebral levels VIII and IX.
Structures travelling between the thorax and abdomen
- Structures that pass between the thorax and the abdomen traverse through the diaphragm or between it and its peripheral attachments.
- The caval opening in the central tendon provides passage for the inferior vena cava at vertebral level T8.
- The esophagus passes through the muscular part of the diaphragm, left of the midline, at vertebral level T10, and with the vagus nerves.
Arterial supply to diaphragm
- Pericardiacophrenic and musculophrenic arteries branch from internal thoracic arteries (a branch of the subclavian artery).
- Superior and inferior phrenic arteries branch from the thoracic and abdominal aorta.
Venous drainage of the diaphragm
- Veins drain into brachiocephalic veins of the neck, the azygos system, and abdominal veins (left suprarenal and inferior vena cava).
Innervation of the diaphragm
- The diaphragm's innervation comes from the phrenic nerves (C3 to C5).
Thoracic walls arteries
- Internal thoracic artery (branch of subclavian artery)
- Anterior intercostal arteries (I -VI); musculophrenic artery (branches)
- Anterior intercostal arteries (VII-XI); superior epigastric artery
- Pericardiophrenic artery
- Lateral thoracic artery (from axillary artery)
- Superior thoracic artery (from axillary artery)
- Superior intercostal artery (from costocervical trunk of subclavian artery)
- Posterior intercostal arteries (I-XI)
- Subcostal artery
Thoracic walls veins
- Anterior intercostal veins drain into internal thoracic vein and tributaries: superior epigastric and musculophrenic veins.
- Posterior intercostal veins drain into azygos vein (right side) and hemiazygos vein (left side).
Nerves of the thoracic walls
- Intercostal nerves I to XI and subcostal nerve are anterior branches of the thoracic spinal nerves.
- Innervate intrinsic muscles, skin, mammary gland and parietal pleura.
- Intercostal neurovascular bundles run in the costal groove and consist of intercostal vein, artery and nerve (VAN).
Thoracic wall puncture
- Intercostal nerve block: needle introduced to lower border of rib and enter intercostal space.
- Pneumothorax avoided by aspiration before injecting anesthetic.
Breast
- Female breast extends from the second to sixth rib and from the parasternal to midaxillary line.
- Mammary tissue is composed of 15-20 lobes separated by connective tissue septa.
- Breast tissue containing glands that produce milk lies in superficial fascia, above deep pectoral fascia and enveloping the pectoral major muscle.
- Areola is the pigmented area surrounding the nipple, it is the area where the lactiferous ducts open at the level of the fourth intercostal space.
- Axillary tail is an extension of mammary tissue projecting superolaterally toward the axilla.
Lymphatic drainage of the breast
- Most of the lymph from the lateral, superior, and inferior quadrants drains to the axillary nodes, especially the pectoralis group.
- Medial quadrant lymph drains to parasternal nodes, along the internal thoracic vessels.
Lower respiratory development complications
- Pulmonary hypoplasia, or aplasia, is a spectrum of malformations characterized by incomplete development of lung tissue.
Pleura and pleural cavity
- The parietal pleura lines the inner surface of the chest wall, diaphragm, and mediastinum.
- Divides into costal, diaphragmatic, mediastinal, and cervical parietal pleura (dome of pleura, pleural cupola).
- Visceral pleura adheres to and covers the lung.
Innervation of the pleura
- Parietal pleura's innervation comes from the intercostal nerves (costal pleura).
- Phrenic nerves supply the central portion of diaphragmatic and mediastinal pleura.
Pleural cavity
- Pleural cavity is a potential space between parietal and visceral pleurae.
- It contains serous fluid, enabling lung movement during breathing.
- Introduction of air into pleural cavity can cause lung collapse (pneumothorax).
Pneumothorax
- Open pneumothorax occurs when a chest wall defect allows air into the pleural cavity.
- Pathophysiology involves air entering the cavity through the defect during inspiration instead of the trachea, there is less resistance to airflow.
- Tension pneumothorax is progressive buildup of air, often due to lung laceration, which leads to mediastinal shift to the opposite hemithorax.
Lungs
- Surfaces and regions of the lungs include costal, mediastinal, and diaphragmatic surfaces.
- The apex projects into the root of the neck and is near the subclavian vein and artery.
Lobes and fissures
- The right lung has 3 lobes (superior, middle, inferior) separated by oblique and horizontal fissures.
- The left lung has 2 lobes (superior and inferior) separated by an oblique fissure.
- The lingula of the left upper lobe corresponds to the middle lobe of the right lung.
- The right lung is slightly larger due to the cardiac impression on the left side.
- The superior lobe of the right lung projects anteriorly to the 4th rib cartilage.
- The middle lobe projects to the anterior surface below the 4th rib
- The inferior lobe resides posteriorly to the 6th cartilage
Lung circulation
- Lungs have a double circulation:
- Systemic circulation: provided by the pulmonary artery.
- Nutrient circulation: provided by bronchial arteries that branch from the internal thoracic artery and the posterior aorta.
Lung innervation
- Lungs receive innervation from the sympathetic trunk (thoracic part) for bronchodilation and vagus nerves for bronchoconstriction.
Lymphatic drainage of lungs
- Lymphatic drainage occurs via superficial and deep plexuses.
- Superficial plexus is under the visceral pleura.
- Deep plexus lies deep in the lungs and drains via pulmonary nodes into tracheobronchial nodes, which bifurcate at the trachea to bronchomediastinal nodes and trunk.
- Bronchomediastinal nodes, located on the right and left sides of the trachea, drain into the right lymphatic duct or the thoracic duct.
Lymphatic drainage (left lung)
- Left lung lymphatic drainage flows to right bronchomediastinal trunk and nodes, then toward the right lymphatic duct, which is considered the primary pathway for metastases in lung cancer.
Lymphatic drainage (thoracic duct)
- Thoracic duct carries lymphatic fluid from the inferior portion of the body (below the diaphragm), including lower limbs, pelvis, abdomen, and left side of the superior body (left superior limb, left half of the thorax and left half of the head).
Breath sounds
- To listen to breath sounds of the superior lobe, place stethoscope above the 4th cartilage of the anterior chest.
- Breath sounds of the right middle lobe are from the anterior chest wall, below the 4th rib.
- Inferior lobes of both lungs can be auscultated from the posterior chest wall.
Pulmonary embolism
- Pulmonary embolism occurs when pulmonary arteries are blocked, most commonly by blood clots from the legs (deep vein thrombosis).
- Causes of pulmonary embolism are often due to venous stasis, trauma, or coagulation disorders.
Lung cancer
- Bronchogenic tumors (lung cancer) can impinge on adjacent structures.
- A Pancoast tumor arises in the lung apex, invades surrounding soft tissues, and may lead to thoracic inlet syndrome, including injuries to subclavian vessels and (frequently) brachial plexus nerve palsy (C8–T1 roots).
- Horner syndrome may result from lung cancer, characterized by miosis (constricted pupil), ptosis (drooping eyelid), anhidrosis (lack of sweating), and flushing (subcutaneous vasodilation).
Respiratory tree
- Conducting zone includes the nose, pharynx, trachea, bronchi, and terminal bronchioles.
- Air is warmed, humidified, and filtered in the conducting zone; cartilage is present only in trachea and bronchi.
- Respiratory zone includes respiratory bronchioles, alveolar ducts, and alveoli, which are sites of gas exchange.
Trachea
- The trachea, a single airway tube, starts at the cricoid cartilage (C6) and bifurcates at the sternal angle (T4).
- It's composed of 16–20 C-shaped cartilages connected by annular ligaments, and lies anterior to the esophagus and posterior to the aortic arch.
- At its bifurcation, the trachea shows a carina (internal keel-like cartilage).
- The posterior part of the trachea is a membranous wall made of longitudinal and circular muscular fibers.
Bronchi
- Aspiration of foreign bodies preferentially occurs in the right main bronchus due to its structure.
- It's shorter, wider, and more vertical than the left bronchus.
- The right primary bronchus divides into 2 or 3 lobar bronchi (secondary), then further into segmental bronchi (tertiary) to supply 10 bronchopulmonary segments.
- The divisions continue until they terminate in alveolar sacs.
Fetal circulation
- Oxygenated blood from the placenta to the fetus travels through the umbilical vein.
- Three vascular shunts (ductus venosus, foramen ovale, ductus arteriosus) bypass the pulmonary circulation in the fetus.
- The ductus venosus bypasses the fetal liver.
- The foramen ovale shunts blood from the right to the left atrium.
- The ductus arteriosus shunts blood from the pulmonary trunk to the aorta.
- These shunts close after birth due to changes in pressure gradients.
Postnatal circulation
- Pressure gradient changes result in closure of the ductus venosus, foramen ovale, and ductus arteriosus after birth.
- Ductus arteriosus closure is associated with smooth muscle contraction and increased oxygen tension.
Fetal circulation remnants
- Medial umbilical ligaments are remnants of umbilical arteries after fetal circulation ceases.
- Ligamentum teres of the liver is the remnant of the umbilical vein.
- Ligamentum venosum is the remnant of the ductus venosus
- Fossa ovalis is the remnant of the foramen ovale.
- Ligamentum arteriosum is the remnant of the ductus arteriosus
- Changes occur within hours and months after birth.
Atrial septal defect
- Atrial septal defect (ASD) is a congenital heart defect more common in females than males.
- Usually results in a left-to-right shunt and non-cyanotic conditions.
Ventricular septal defect
- Membranous ventricular septal defect (VSD) results in a left-to-right shunt.
- Characterized by excessive fatigue upon exertion, which is not cyanotic.
- The condition can lead to pulmonary hypertension and pulmonary vascular disease.
Patent ductus arteriosus
- Patent ductus arteriosus (PDA) is a failure of the ductus arteriosus to close after birth.
- In fetal circulation, the shunt is left-to-right.
- In neonatal period, the pulmonary resistance decreases, causing the shunt to become left-to-right and non-cyanotic.
Tetralogy of Fallot
- Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect.
- Characterized by pulmonary stenosis, right ventricular hypertrophy, overriding aorta receiving blood from both ventricles, and ventricular septal defect (VSD).
Transposition of great vessels
- Transposition of great vessels (TGV) occurs due to failure of the aortopulmonary septum to spiral.
- Most infants die within months without surgical intervention.
- The aorta arises from the right ventricle, and the pulmonary artery arises from the left ventricle, causing a right-to-left shunt.
- Cyanotic condition – usually not compatible with life.
Persistent truncus arteriosus
- Persistent truncus arteriosus (PTA) is characterized by incomplete development of the aorticopulmonary septum, leading to a single large vessel receiving blood from both ventricles.
- Results in right-to-left shunt and cyanosis.
Heart
- Middle mediastinum is a central region between two pleural cavities containing the pericardium, heart and great vessels (ascending aorta, pulmonary trunk), and phrenic nerves.
- Pericardium is a fibroserous membrane covering the heart.
Pericardial cavity
- Pericardial cavity is a potential space between serous pericardial layers, contains a small amount of fluid that enables heart movement.
Cardiac tamponade
- Cardiac tamponade is the pathological accumulation of fluid in the pericardial cavity which compresses the heart.
Heart Surfaces
- Anterior surface of the heart is primarily formed by the right ventricle, right atrium, and an area of the left ventricle.
- Diaphragmatic surface is mainly the left ventricle.
- Left pulmonary surface is predominately formed by the left ventricle, and forms the cardiac impression on the diaphragmatic surface.
- Right pulmonary surface is mainly the right atrium.
Heart borders
- Right border: right atrium between superior and inferior venae cavae.
- Inferior border: right ventricle and part of the left ventricle.
- Left border: left ventricle with a small portion of left auricle.
- Superior border: right and left atria and auricles, ascending aorta, and pulmonary trunk.
Heart wall structure
- Endocardium: innermost layer of the heart, continuous with vascular endothelium of blood vessels.
- Myocardium: middle layer, containing complex muscle fibers.
- Epicardium: outermost layer, part of the pericardium, a serous membrane.
Heart wall
- The heart wall is created by three muscular layers:
- External: oblique.
- Intermediate: strongest circular.
- Internal: longitudinal.
Heart position
- The heart lies approximately at the level of T6-T9 vertebrae, posterior and superior in the thorax as well as to the right of the chest cavity.
- The heart crown is created by its base, enclosing the origins of the great vessels.
- The heart's apex is mainly the left ventricle, lying posteriorly to the 5th intercostal space and medially to the midclavicular line.
- The atria are demarcated from the ventricles by the coronary sinus; likewise, anterior and posterior interventricular grooves demarcate the ventricles.
Heart surface projections
- Upper right heart aspect projects to the 3rd right costal cartilage.
- Lower right heart aspect projects to the 6th right costal cartilage.
- Upper left heart aspect projects to the 2nd left costal cartilage.
- The heart's apex is at the midclavicular line of the left 5th intercostal space
Chambers of the heart
- The right atrium receives blood from the superior (SVC), inferior (IVC) venae cava, and coronary sinus.
- The right auricle, a muscular pouch, increases the atrium's capacity, originating from fetal atria.
- The anterior part of the right atrium has pectinate muscles.
- The posterior part (sinus venarum) is smooth and houses openings for SVC, and IVC as well as the coronary sinus
Right atrium
- Crista terminalis is a ridge separating the smooth (sinus venarum) and rough (pectinate muscles) parts of the right atrium.
- The superior end of the crista terminalis contains the sinoatrial node.
- Fossa ovalis is a remnant of the foramen ovale.
Right ventricle
- The right ventricle forms most of the anterior surface of the heart.
- Superiorly, it tapers into the conus arteriosus, which leads to the pulmonary trunk.
- The ventricular interior displays trabeculae carneae (muscular elevations).
- Papillary muscles, originating from the ventricular walls, project into the ventricular cavity and anchor the tricuspid valve cusps via chordae tendineae.
Right ventricle (Papillary muscles)
- Anterior papillary muscle is the largest, arising from the anterior ventricular wall.
- Posterior papillary muscle arises from the posterior ventricular wall and is sometimes composed of several parts.
- Septal papillary muscle, originates from the interventricular septum (IVS).
Right ventricle (Interventricular septum)
- Interventricular septum (IVS) is made up of both muscular and membranous parts.
- The septal cusp of the tricuspid valve attaches to the membranous part of the IVS.
- Septomarginal trabecula is a muscular bundle traversing the right ventricle from the inferior IVS to the base of the anterior papillary muscle which carries part of the right branch of the atrioventricular bundle.
Left atrium
- Left atrium forms the heart's base.
- Superior and inferior pulmonary veins deliver oxygenated blood from the lungs to the left atrium.
- The left auricle, having pectinate muscles, displays a trabeculated wall.
- The bicuspid (mitral) valve sits between the left atrium and left ventricle.
Left ventricle
- Blood enters the left ventricle via the mitral valve and is pumped to the aorta.
- Trabeculae carneae are usually thicker in the left ventricle than in the right.
- Papillary muscles (anterior and posterior) are attached to the mitral valve cusps via chordae tendineae.
- The aortic vestibule leads to the aortic semilunar valve.
Cardiac skeleton and valves
- The heart has four valves attached to the fibrous rings of dense collagen forming the cardiac skeleton.
- Fibrous rings surround the atrioventricular and semilunar valves.
- Fibrous trigons (left and right) and tendon of infundibulum are part of the framework.
Cardiac skeleton and valves
-
Valves include:
-
Right atrioventricular valve / tricuspid (5th intercostal space, right sternal line)
-
Left atrioventricular valve / mitral (5th intercostal space, left midclavicular line)
-
Aortic valve (2nd intercostal space, right sternal line)
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Pulmonary valve (2nd intercostal space, left sternal line)
Cardiac skeleton and valves (Heart sounds)
-
Heart sounds (S1 and S2) result from valve closure.
-
S1 from atrioventricular valve closure during ventricular systole; S2 from semilunar valve closure.
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Murmurs are heart diseases characterized by valvular insufficiency or stenosis.
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During ventricular systole, mitral valve should be closed, aortic valve should be opened. Typical systolic defects are mitral insufficiency (regurgitation) and aortic stenosis.
Coronary arteries
- Coronary arteries originate from the aortic sinuses.
- Right coronary artery (RCA) coursing through the coronary sulcus supplies most parts of the right atrium and ventricle and branches include: sinoatrial (SA) nodal, right marginal, posterior interventricular (posterior descending).
- Left coronary artery (LCA) courses between the left auricle and ventricle and divides into the left anterior descending (LAD) and circumflex arteries.
- The LAD descends within the anterior interventricular groove and supplies the anterior wall, anterior 2/3 of the interventricular septum, bundle of His, and apex of the left ventricle.
- The circumflex artery follows the left atrioventricular groove and supplies blood to the lateral and posterior aspects of the left ventricle, and the left border of the heart.
Coronary occlusion
- Myocardial infarction (MI) is often associated with LAD occlusion (50%), less frequently with RCA occlusion (30%), and rarely with circumflex artery obstruction (20%).
Cardiac veins
- Coronary veins accompany the coronary arteries and drain deoxygenated blood from the heart muscle to the right atrium via:
- Coronary sinus is the largest coronary vein.
- Great cardiac vein lies in the anterior interventricular groove.
- Middle cardiac vein lies in the posterior interventricular groove.
- Small cardiac vein
- Venae cordis minimae or Thebesian veins open directly into heart chambers.
Conduction system of the heart
- The conduction system of the heart is composed of specialized cardiac muscle cells and conducting fibers (not nervous tissue) that produce and conduct electrical impulses rapidly.
- Parts of the Conduction system include:
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- Atrioventricular bundle (bundle of His)
- Purkinje fibers
Conduction system of the heart (Innervation)
- Cardiac plexus is created by sympathetic and parasympathetic fibers.
- Sympathetic stimulation increases heart rate.
- Pain fibers generally travel with sympathetic fibers back to spinal cord segments T1–T5.
- Parasympathetic stimulation slows heart rate. Sensory nerves of the heart travel with the vagus nerve.
Mediastinum
- Superior mediastinum: lies between the manubrium of the sternum and the bodies of the thoracic vertebrae (T1-T4), contains the thymus (present in childhood), brachiocephalic veins, superior vena cava, vagus nerve, and phrenic nerves, among others.
- Anterior mediastinum: located between the sternum and the anterior surface of the pericardium; contains the areolar tissue, anterior mediastinal lymph nodes, and the internal thoracic vessels (artery and vein).
- Posterior mediastinum: lies between the posterior surface of the pericardium and the thoracic vertebrae (T5-T12); contains the descending thoracic aorta, esophageal structures, posterior intercostal vessels, and the vagus and phrenic nerves.
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Description
Test your knowledge on the anatomy of the heart and related structures with this quiz. It covers questions about heart valves, musculature, and thoracic boundaries. Ideal for students studying cardiology or anatomy.
