Podcast
Questions and Answers
What is the region between the neck and the abdomen called?
What is the region between the neck and the abdomen called?
Thorax
What are the two main functions of the thorax?
What are the two main functions of the thorax?
Protect thoracic organs and provide attachment for upper extremities, intercostal muscles, diaphragm, and abdominals
Which structures make up the skeleton of the thorax?
Which structures make up the skeleton of the thorax?
What are the two main types of thoracic apertures?
What are the two main types of thoracic apertures?
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What are the three types of intercostal muscles?
What are the three types of intercostal muscles?
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What does the acronym VAN stand for, when referring to neurovascular bundles?
What does the acronym VAN stand for, when referring to neurovascular bundles?
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What is the name of the notch located at the level of T2 vertebrae?
What is the name of the notch located at the level of T2 vertebrae?
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What is the name of the bony projection located at the level of T10 vertebrae?
What is the name of the bony projection located at the level of T10 vertebrae?
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What is the name of the bony structure that marks the junction between the manubrium and the body of the sternum?
What is the name of the bony structure that marks the junction between the manubrium and the body of the sternum?
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What are the three types of ribs?
What are the three types of ribs?
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Which of the following best describes the function of the diaphragm?
Which of the following best describes the function of the diaphragm?
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What is the name given to the space between the parietal and the visceral layers of the serous pericardium?
What is the name given to the space between the parietal and the visceral layers of the serous pericardium?
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The fibrous pericardium is a tough, outer layer that surrounds the heart.
The fibrous pericardium is a tough, outer layer that surrounds the heart.
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Which of the following statements is true about the right ventricle?
Which of the following statements is true about the right ventricle?
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What is the function of the mitral valve?
What is the function of the mitral valve?
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What are the two major branches of the left coronary artery?
What are the two major branches of the left coronary artery?
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What is the name given to the small venous structure that drains blood from the heart?
What is the name given to the small venous structure that drains blood from the heart?
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What is the name of the specialized heart tissue that acts as the pacemaker of the heart?
What is the name of the specialized heart tissue that acts as the pacemaker of the heart?
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Which of the following structures is involved in the conduction of electrical signals from the SA node to the ventricles?
Which of the following structures is involved in the conduction of electrical signals from the SA node to the ventricles?
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Sympathetic stimulation slows down the heart rate, while parasympathetic stimulation speeds it up.
Sympathetic stimulation slows down the heart rate, while parasympathetic stimulation speeds it up.
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What is the name of the primary nerve that controls the heart's function?
What is the name of the primary nerve that controls the heart's function?
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What is the name of the nerve that controls the diaphragm?
What is the name of the nerve that controls the diaphragm?
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What is the name of the condition in which the pericardial cavity fills with fluid, compressing the heart?
What is the name of the condition in which the pericardial cavity fills with fluid, compressing the heart?
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Which of the following best describes the function of the anterior interventricular branch of the left coronary artery, often called the "widowmaker"?
Which of the following best describes the function of the anterior interventricular branch of the left coronary artery, often called the "widowmaker"?
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The heart is located more on the left side of the chest cavity (2/3rds left).
The heart is located more on the left side of the chest cavity (2/3rds left).
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What is the name of the valve that prevents backflow from the right ventricle to the right atrium?
What is the name of the valve that prevents backflow from the right ventricle to the right atrium?
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Which of the following structures is NOT involved in the parasympathetic innervation of the heart?
Which of the following structures is NOT involved in the parasympathetic innervation of the heart?
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Study Notes
Thorax & Ribs
- The thorax is the region between the neck and the abdomen
- It protects thoracic organs (heart and lungs)
- It provides attachment for the upper extremities (UE)
- Intercostal muscles, diaphragm, and abdominals form rigid yet moveable walls
Thorax - Surface Anatomy
- Includes lines and segmented levels
- Ribs 1-12 and thoracic vertebrae 1-12
- Sternum
- Superior (thoracic outlet) and Inferior apertures
Thorax - Muscles
- Intercostals (external, internal, and innermost)
- Subcostal
- Transversus thoracis
Thorax - Neurovascular Bundles
- VAN (vein, artery, nerve)
- Diaphragm (superior to inferior)
Thorax - Surface Anatomy Detail
- Clavicles
- Suprasternal notch (T2)
- Xiphisternal junction (T9)
- Sternal angle (2nd costal cartilage and T4/T5)
- Xiphoid process (T10)
- Costal margin
Thorax - Axillary Lines
- Anterior
- Mid-axillary
- Posterior
Thorax - Bony Framework
- 12 ribs
- Costal cartilages
- Sternum (manubrium, body, xiphoid process)
- Thoracic vertebrae
Thorax - Types of Ribs
- True ribs (ribs 1-7): Articulate via costal cartilages with the sternum
- False ribs (ribs 8-10): Articulate via costal arches (don't attach directly to sternum)
- Floating ribs (ribs 11-12)
Thorax - Thoracic Apertures
- Superior aperture: Manubrium, Rib 1 and costal cartilage, T1 vertebrae
- Inferior aperture: T12 vertebrae, Ribs 11 and 12
Thorax - Superior Aperture
- Passageway for esophagus, trachea, great vessels & nerves of head/neck, & vessels of upper limbs, Apex of the lung
- Careful when dry needling around neck – may puncture top of lungs*
Thorax - Inferior Aperture
- Diaphragm is pushed upward to the sternum
- Innervation: phrenic nerve (C3, C4, C5)
- Costal margin
Thorax - Intercostal Muscles
- External intercostals ("hands in pockets")
- Internal intercostals ("hands on chest")
- Innermost intercostals
Thorax - Intercostal Spaces
- Muscles: external intercostal, internal intercostal, innermost intercostal
- Neurovascular bundle: intercostal vein, intercostal artery, intercostal nerve
- Intercostal nerve (anterior ramus): medial br, lateral br, anterior cutaneous branch, innermost intercostal, anterior br, lateral cutaneous branch, posterior br
Thorax - Segmented Levels
- Clavicle - C4
- Nipples (male - T4, females - T5)
- Umbilicus - T10
- Inguinal region - L1
Sympathetic Nervous System
- Cardiopulmonary & Abdominopelvic Splanchnics: How sympathetic fibers arrive at internal structures (heart, lungs, organs)
- It goes everywhere: Innervates internal structures + extremities, head
- Short pre-synaptic / long post-synaptic neuron
- Sympathetic chain ganglia: Along vertebral column, entire length
- Spinal cord: T1-L1/2: Cell bodies located
Sympathetic Neurons Presynaptic Cell Bodies
- It originates in spinal cord (T1-L2/3)
- Located more specifically in lateral horns of gray matter of spinal cord
- IML= intermediolateral cell column
- Conus medullaris: L1-L2
Sympathetic Neurons Presynaptic Neuron
- 2-neuron system
- Cell bodies of the first neuron are in the IML of the spinal cord
- The presynaptic neuron is short
- It only travels to the sympathetic chain ganglia on each side of vertebral column
Sympathetic Neurons Postganglionic Neuron
- Long post-synaptic neuron
- Locations: Body wall and limbs
- Functions: vasomotion, sudomotion, pilomotion
Thoracic Apertures
- Superior aperture
- Inferior aperture
Intercostal Muscles
- External intercostals
- Internal intercostals
- Innermost intercostals
Pericardium and the Heart
- Pericardium: sac enclosing the heart and roots of great vessels
- Two layers: fibrous pericardium and serous pericardium
- Function: Keeps heart in position & protects it, facilitates movement, separates from other structures, fuses with the central tendon of diaphragm
- It aids in open-heart surgery without pleural cavity problems
Pericardium - Clinical Correlations
- Pericarditis: Inflammation of the pericardium, causes chest pain
- Pericardial effusion: Fluid build up, compresses heart, causes reduced cardiac output, tachcardia, cardiac tamponade
Heart
- 4 chambers: 2 atria and 2 ventricles
- Venous input: SVC (superior vena cava), IVC (inferior vena cava), Coronary sinus
- Oxygen-poor blood: Venous system to heart via pulmonary arteries
- Oxygen-rich blood: Pulmonary veins, aortic blood, coronary vessels
Valves of the Heart
- Tricuspid valve: Between right atrium and ventricle (3 leaflets, 3 papillary muscles with chordae tendinae)
- Mitral valve: Between left atrium & ventricle (2 leaflets, 2 papillary muscles with chordae tendinae)
- Aortic valve
- Pulmonary valve
Semilunar Valves (Cusps)
- Aortic valve
- Pulmonary valve
- 3 cusps, concave when viewed from above
- No chordae tendinae
- Prevent backflow
Heart and the Great Vessels- Chambers
- 4 chambers, right atrium, left atrium, right ventricle, left ventricle
- Oxygenated blood enters left atrium
- Blood returns to the heart via superior and inferior vena cava
- Oxygenated blood returns to the right atrium via pulmonary veins
Heart and Great Vessels in Situ/Heart and Great Vessels-con't
- SVC
- IVC
- Aorta
- Pulmonary trunk
- Openings, arteries and veins
Heart and the Great Vessels - Veins
- R. Internal jugular vein
- R. Subclavian vein
- R & L Brachiocephalic vein (to SVC)
- L. Internal jugular vein
- L. Subclavian vein
Heart and the Great Vessels - Arteries
- R. Brachiocephalic trunk
- R. Subclavian artery
- L. Common carotid artery
- L. Subclavian artery
- Aorta
Branches from Aorta
- Right common carotid artery
- Right subclavian artery
- Brachiocephalic trunk
- Left common carotid artery
- Left subclavian artery
- Arch of aorta
- Ascending aorta
- Descending (thoracic) aorta
Conducting System of the Heart
- SA node: at the junction of the SVC and the right atrium
- Pacemaker
- Normal rhythm: 70 bpm
- Spreads through muscle of both atria
- Cardiac plexus (both SNS and PNS supply)
- Signal to AV node
Conducting System of the Heart (cont.)
- AV node: located in the interatrial septum near the coronary sinus
- Activated from SA node signal
- Propagates through AV bundle of His
- Divides into right and left bundles, each going to ventricle
- Moderator band in right ventricle to the anterior papillary muscle
Innervation of the Heart
- Sympathetic supply: Cardiopulmonary splanchnics and post-synaptic sympathetics
- Parasympathetic supply: Presynaptic fibers of the vagus nerve and post-synaptic cell bodies in intrinsic ganglia near SA and AV nodes
Clinical Implications
- Related topics, including possible conditions and testing
Thoracic Viscera
- Cardiopulmonary splanchnic nerves exit the ganglia medially instead of laterally, to the central structures
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