Region 1 - Thorax Flashcards
What are the boundaries of the superior thoracic aperture?
Body of T1
1st pair of ribs and their cartilages
Superior border of manubrium
What is the function of the superior thoracic aperture?
Passage of structures between thorax and neck/upper limb
What are the boundaries of the inferior thoracic aperture?
Body of T12
11th and 12th pairs of ribs
Costal cartilages of ribs 7-10 (costal margin)
Xiphisternal joint
What is the function of the inferior thoracic aperture?
Passage of structures between thorax and abdomen
What are the name and type of joints between vertebral articulate processes?
Zygopophysial (facet) joints
Synovial plane
What do the heads of the typical ribs articulate with?
Body of own vertebra
Body of vertebra above
IV disc (via crest)
What do the tubercles of the typical ribs articulate with?
Articulate part with transverse process of own vertebra
What is the function of the non-articular part of a typical rib?
Costotransverse ligament attachment
What are the numbers of the typical ribs?
3-9
What separates the articulate facets on the head of a typical rib?
Crest
What defines a true rib? What numbers are the true ribs?
Connect directly to sternum via own cartilage
1-7
What defines a false rib? What numbers are these?
Connects to sternum indirectly via cartilage of ribs above
8-10
What defines a floating rib? What numbers are these?
Does not connect to sternum
11 and 12
What is the name for the most curved part of the body of a rib?
Costal angle
Where is the costal groove found on the rib?
Internal surface of the inferior border of the body of the rib
What is the function of the costal groove?
Protects intercostal NVB
What are the atypical features of rib 1?
Single facet in head for T1 (C7 has no articulate surface)
Grooves for subclavian vessels
- On superior surface
What is the function of the scalene tubercle?
Separates grooves for subclavian vessels on superior surface of rib 1
Attachment point for anterior scalene muscle
What is the function of the rough area on the superior surface of rib 2?
Tuberosity for serrated anterior
What ribs don’t have a neck or tubercle?
11th and 12th ribs
What type of cartilaginous joints are the IV discs and what is the other name for this type of joint?
Secondary
Symphysis
What type of joint does rib 1 have with the sternum?
Primary cartilaginous (synchondrosis)
What types of joints do ribs 2-7 have with the sternum?
Synovial plane
What types of joints are the interchondral joints?
Synovial plane (between 6+7, 7+8 and 8+9) Fibrous joint (between 9+10)
What is the axis of the upper ribs (1-6) and how does this affect their movement during respiration? What is the movement called?
More lateral
Ribs move up and out (anteriorly) - Pump handle movement
What is the axis of the lower ribs (7-12) and how does this affect their movement during respiration? What is the movement called?
More anteroposterior
Ribs flare out more laterally - bucket handle movement
What are the changes in dimension during respiratory movements and how are hose achieved?
Anteroposterior - Sternum moves anteriorly and superiorly
Lateral - Lower rib cage moves outwards
Vertical - Diaphragm descends
What are the secondary muscles of respiration?
Scalene muscles
Serrated posterior superior and inferior
What nerve(s) innervate the pectoralis major?
Medial pectoral (C8, T1) Lateral pectoral (C5-C7)
What nerve(s) innervate pectoralis minor?
Media pectoral nerve (C8, T1)
What nerves supply the external oblique and rectum abdominis?
Anterior rami of T7-T12
What supplies serratus anterior?
Long thoracic nerve (C5-C7)
What supplies serratus posterior superior?
2nd-5th intercostal nerves
What supplies the serratus posterior inferior?
Anterior rami T9-T12
What innervates the anterior scalene muscle?
Anterior rami C3-C7
What innervates the middle scalene muscle?
Anterior rami C4-C7
What innervates the posterior scalene muscle?
Anterior rami C5-C7
What direction do the external intercostal muscles move in?
Downwards and forwards (hands in pockets)
Where do the external intercostal muscles run from and to?
From tubercles of ribs to costochondral junction
What are the external intercostal muscles replaced by anteriorly?
External intercostal membrane
What function do the external intercostal muscles serve?
Raise the ribs on inspiration
What direction do the internal intercostal muscles move in?
Downards and backwards
Where do the internal intercostal muscles run from and to?
Sternum to angle of rib
What are the internal intercostal muscles replaced by posteriorly?
Internal intercostal membrane
What are the functions of the internal intercostal ribs?
Depress ribs (interosseous part) Raise ribs (interchondral part)
Where do the innermost intercostal muscles lie?
Deep to lateral part of internal intercostals
What direction do the innermost intercostal muscles run in?
Downwards and backwards
Where are the subcostal muscles found?
Near angle of ribs
How can the subcostal muscles be differentiated from intercostal muscles?
Span 1 or 2 intercostal spaces
What muscle radiates from the sides of the sternum to costal cartilages 2-6?
Transversus thoracis
What are the contents of an intercostal space?
Intercostal muscles Neurovascular bundle: - Intercostal vein (most superior) - Intercostal artery - Intercostal nerve (most inferior)
Where does the intercostal neurovascular plane run?
In the costal groove of the rib between the internal and innermost intercostal muscle layers
From what artery do the 1st and 2nd posterior intercostal arteries from? Where does this artery originate?
Supreme intercostal artery from costocervical trunk (branch of subclavian)
Where do posterior intercostal arteries 3-11 and the subcostal artery arise from?
Thoracic aorta
Where do the 1st-6th anterior intercostal arteries arise from?
Internal thoracic artery (branch of subclavian)
Where do the 7th-9th anterior intercostal arteries arise from?
Musculophrenic artery (from internal thoracic)
Where does the superior epigastric artery arise from?
Internal thoracic artery
Where do the anterior intercostal veins drain to?
Internal thoracic veins
Where do the posterior intercostal veins on the right side from the 2nd-4th spaces drain to?
Right superior intercostal vein (draining to azygos)
Where do the posterior intercostal veins on the right side from the 2nd and 3rd spaces drain to?
Left superior intercostal vein (draining to left brachiocephalic +/- accessory hemiazygos)
What veins drain the 1st intercostal spaces?
Supreme intercostal veins (drain to brachiocephalic veins)
Where does venous blood drain to from posterior intercostal spaces on the right side (5-11 and subcostal)?
Azygos vein
Where does venous blood drain to from posterior intercostal spaces on the left side (9-11 and subcostal)?
Hemiazygos vein
Where does venous blood drain to from posterior intercostal spaces on the left side (4-8)?
Accessory hemiazygos
Where do lateral mammary branches arise from?
Lateral thoracic artery (from axillary)
Where do medial mammary branches arise from?
Internal thoracic artery
Where does 75% of lymph from the breast drain to?
Axillary nodes
Where else can breast lymph drain to?
Parasternal nodes (Abdominal nodes)
What are the four parts of the parietal pleura?
Cervical
Costal
Diaphragmatic
Mediastinal
What is the pulmonary ligament and what is its function?
Sleeve of pleura hanging below lung root
Allows for hilar structures to expand
What does the endothoracic fascia do?
Attaches costal parietal pleura to the thoracic wall
What is the function of the fibrous suprapleural membrane?
Prevents lung expansion into neck
What are the attachments of the fibrous suprapleural membrane?
1st rib
C7 transverse process
What is the fibrous suprapleural membrane continuous with?
Endothoracic fascia
What are the surface markings of the lungs/visceral pleura?
Midclavicular line - Rib 6
Midaxillary line - Rib 8
Scapular line - Rib 10
What are the surface markings of the parietal pleura?
Midclavicular line - Rib 8
Midaxillary line - Rib 10
Scapular line - Rib 12
What forms the costodiaphragmatic recess?
Parietal pleura extending over dome of diaphragm
Why is the left costomediastinal recess bigger than the right?
Large cardia impression
What are the three surfaces of each lung?
Costal
Diaphragmatic
Mediastinal
What are the three borders of each lung?
Anterior
Posterior
Inferior
Where do the pulmonary veins lie in the lung hilum?
Most anterior and inferior
Where are the pulmonary arteries located in the lung hilum?
Superiorly
Where is the bronchus located in the lung hilum?
Posteriorly
Where does the phrenic nerve run in relation to the lung hilum?
Anterior
Where does the vagus nerve run in relation to the lung hilum?
Posterior
What does the left recurrent laryngeal nerve loop under?
Arch of aorta
What does the right recurrent laryngeal nerve loop under?
Right subclavian artery
Where does the azygos vein lie in regards to the lungs?
Posterior to the right hilum
Where does the SVC run in regards to the lungs?
Anterior to the right hilum
How many segmental bronchi are there in the right lung lobes?
5 in lower lobe
3 in upper lobe
2 in middle lobe
How many segmental bronchi are there in the left lung lobes?
5 in upper lobe
5 in lower lobe
What do the segmental bronchi divide into?
Bronchioles:
- Conducting
- Terminal
- Respiratory
What do the bronchioles divide into?
Alveolar ducts
What are the boundaries of the anterior mediastinum?
Body of sternum Pericardium Transverse thoracic plane Diaphragm (Pleural laterally)
What is the transverse thoracic plane?
Line from sternal angle to T4/5 IV disc
What are the contents of the anterior mediastinum?
Loose connective tissue
Fat
Lymphatics
Thymus
What are the contents of the middle mediastinum?
Heart and pericardium Roots of great vessels: - Lower half SVC - Pulmonary trunk - Ascending aorta - Right and left pulmonary veins Phrenic nerves Lung root structures
Where does the right phrenic nerve run in relation to the heart?
Over the pericardium of the right atrium
Where does the left phrenic nerve run in relation to the heart?
Over pericardium of left atrium and ventricle
What does the fibrous pericardium blend with?
Superiorly - Tunica adventitia of great vessels
Inferiorly - Central tendon of diaphragm
What is the other name for the visceral serous pericardium?
Epicardium
Where is the pericardial cavity?
Between the parietal and visceral serous pericardium
What is the transverse pericardial sinus?
Passage between venous and arterial mesocardia
What vessel(s) lie anterior to the transverse pericardial sinus?
Aorta
Pulmonary trunk
What vessel(s) lie posterior to the transverse pericardial sinus?
SVC
What is the space behind the heart called?
Oblique pericardial sinus
What forms the superior border of the heart?
Right and left atria and auricles
What forms the right border of the heart?
Right atrium
What forms the left border of the heart?
Left ventricle and left auricle
What forms the inferior/diaphragmatic surface of the heart?
Right ventricle
What forms the apex of the heart?
Left ventricle
What rough shape is the heart?
Trapezoidal
What is the ligamentum arteriosum?
A fibrous remnant of ductus arteriosis
What structure runs posterior to the ligamentum arteriosum in adults?
Left recurrent laryngeal nerve
What are the main branches of the right coronary artery?
SA nodal
Right marginal
Posterior interventricular
AV nodal
What are the main branches of the left coronary artery?
Anterior interventricular: - Diagonal branch Circumflex: - Left marginal (- SA nodal) (- Posterior interventricular)
What parts of the heart does the right coronary artery supply?
Right atrium and most of right ventricle
SA (usually) and AV nodes
Posterior third of IV septum
Part of left ventricle
What parts of the heart does the left coronary artery supply?
Left atrium and most of left ventricle
Anterior 2/3 of IV septum
AV bundle
Part of right ventricle
What cardiac veins drain directly to the right atrium?
Anterior cardiac veins
Where do the other cardiac veins drain to first?
Coronary sinus
What vein runs alongside the anterior IV artery?
Great cardiac vein
What vein runs alongside the posterior IV artery?
Middle cardiac vein
What vein rungs alongside the right marginal artery?
Small cardiac vein
What is the sinus venarum?
Smooth, posterolateral, internal surface of the right atrium
What is found in the sinus venarum?
Orifices for SVC, IVC and coronary sinus
What are the muscular ridges in the atrial and auricle walls called?
Musculi pectinati
What is the junction between the sinus venarum and pectinate muscles in the right atrium called and what is found here>
Crista terminalis SA node (near SVC opening)
What is the fossa ovalis?
Remnant of foramen ovale
What structure is unique to the right ventricle and what is its function?
Septomarginal trabecula (moderator band) Carries part of right bundle branch to anterior papillary muscle
What are the muscular ridges in the ventricular walls?
Trabeculae carneae
Where heart valves are semilunar?
Pulmonary and aortic
What are the cusps of the pulmonary valve?
Left, right and anterior
What are the cusps of the aortic valve?
Left, right and posterior
When do the semilunar valves close?
Under low ventricular pressure (backflow of blood in pulmonary trunk and aorta close the valve)
When do the cuspid valves close?
Under high ventricular pressure (ie systole)
What is the function of the fibrous skeleton in the heart?
Supports valves
Electrical insulation between atria and ventricles
What nerves innervate the SA node?
Autonomic from cardiac plexus
What supplies PNS innervation to the heart?
Vagus nerve
What supplies SNS innervation to the heart?
T1-T5/6 spinal nerves via cervical and superior thoracic paravertebral ganglia
What are the boundaries of the superior mediastinum?
Manubrium Bodies of T1-T4 vertebrae Transverse thoracic plane Thoracic inlet Parietal pleura
What are the contents of the superior mediastinum?
Thymus Brachiocephalic veins and SVC Arch of aorta (and its 3 branches) Trachea Oesophagus Phrenic and vagus nerves Lymphatics and thoracic duct
What structures are ONLY found in the superior mediastinum in adults?
Thymus
Brachiocephalic veins
Arch of aorta
Trachea
Where does the right vagus nerve run in the superior mediastinum?
Anterior to right subclavian artery
Where does the left vagus nerve run in the superior mediastinum?
Between left common carotid and left subclavian arteries
What plexuses does the vagus nerve give branches to in the thorax?
Cardiac plexus (deep to arch of aorta) Right and left pulmonary plexuses (on right and left main bronchi)
What vagus nerve forms most of the anterior oesophageal vagal plexus?
Left
What vagus nerve forms most of the posterior oesophageal vagal plexus?
Right
What do the oesophageal vagal plexuses continue as?
Vagal trunks
What are the root values of the phrenic nerve?
C3, C4 and C5
What is the right phrenic nerve related to?
Right brachiocephalic vein
SVC
Pericardium over right atrium
Right lung hilum (anterior to it)
Where does the right phrenic nerve pierce the diaphragm and at what level?
Near caval opening
T8
Where does the left phrenic nerve lie?
Between left subclavian artery and vein
To the left of the arch of aorta anterior to vagus
Anterior to left hilum
Where does the left phrenic nerve pierce the diaphragm?
To the left of the pericardium
Where does the trache begin?
C6/7 (below larynx)
What is the name for the division of the trachea and at what level is this?
Carina
T4/5 (transverse thoracic plane)
What is the structure of the trachea anteriorly?
C-shaped cartilages
What lies posterior to the trachea? What is its function?
Trachealis muscle
Accommodates expansion of oesophagus
Where does the oesophagus begin?
C6 (continuation of pharynx)
Where does the oesophagus lie in relation to the aorta?
Initially to the right
Crosses anteriorly prior to piercing diaphragm?
At what level does the oesophagus pierce the diaphragm?
T10
What structures cause the three constrictions of the oesophagus?
Arch of aorta
Left bronchus
Diaphragm
What are the boundaries of the posterior mediastinum?
Transverse thoracic plane Bodies of T5-T12 vertebrae Pericardim Diaphragm Parietal pleura
What are the contents of the posterior mediastinum?
Thoracic part of descending aorta Azygos vein Hemiazygos and accessory hemiazygos veins Vagus nerves Greater, Lesser and Least splanchnic nerves Sympathetic chain Oesophagus Thoracic duct Lymphatics
At what level does the aorta pass through the diaphragm?
T12
What sympathetic trunk level ganglia contribute to the greater splanchnic nerve?
T5-T9
What sympathetic trunk level ganglia contribute to the lesser splanchnic nerve?
T10 and T11
What sympathetic trunk level ganglia contribute to the least splanchnic nerve?
T12
What do the thoracic splanchnic nerves carry? Where to?
Presynaptic SNS fibres to abdominal viscera
What abdominal ganglia do the greater splanchnic nerves supply?
Coeliac
Superior mesenteric
What abdominal ganglia do the lesser splanchnic nerves supply?
Superior mesenteric
Aorticorenal
What abdominal ganglia do the least splanchnic nerves supply?
Aorticorenal
What structures pass through the aortic hiatus? What level is this at?
Aorta, thoracic duct and azygos vein
T12
What structures pass through openings in the diaphragmatic crura?
Greater and lesser splanchnic nerves
What structures pass behind the medial arcuate ligament (of the psoas major)?
Least splanchnic nerve
Sympathetic trunk