Thorax Flashcards
True ribs
Attach directly to sternum
1st-7th ribs
False ribs
Indirect attachment to sternum (cartilages are connected to cartilage of the rib above them)
8th, 9th, usually 10th ribs
Floating ribs
Do not connect to sternum
11th, 12th (sometimes 10th) ribs
Typical ribs and their components
3rd-9th ribs
- Head (2 facets to articulate with 2 vertebrae)
- Neck
- Tubercle (articulates with TP)
- Body
Atypical ribs and their components
1st, 2nd, 10th-12th ribs
Head (1 facet, single vertebra)
Intercostal spaces
Separate the ribs and their costal cartilages from one another
Named according to rib forming superior border of the space
(4th intercostal space is between 4th and 5th ribs)
Space below 12th rib
Subcostal space
Parts of the sternum
Manubrium
Body
Xiphoid process
Manubrium
Trapezoidal
Widest, thickest part of sternum
Jugular notch
Concave center of superior border of manubrium
Manubriosternal joint
Junction of manubrium and the body of the sternum
Sternal angle
Sternal angle (of Louis)
Manubriosternal joint
Body of sternum
Longer, narrower, thinner than manubrium
Located T5-T9 level
Xiphoid process
Smallest part of sternum
Thin and elongated
Inferior end lies at T10
Becomes ossified around age 40
May fuse with sternal body in elderly
Superior thoracic aperture
Borders: T1 to top of manubrium to 1st pair of ribs
Contents: esophagus, trachea, nerves & BV supply the head, neck and UE
Inferior thoracic aperture
Borders: T12 to 11-12th ribs, costal margins of 7-10th ribs, xiphisternal joint
Content: allows esophagus/IVC/aorta to pass inferior to abdominal cavity
Much more spacious than superior
Costovertebral joints
Posterior thorax
Rib articulation with vertebral body
Costotransverse joints
Posterior thorax
Rib articulation with TP
Intervertebral joints
Posterior thorax
Disc and facets
Costochondral joints
Anterior thorax
Rib articulation with chondral cartilage
Sternocostal joints
Anterior thorax
Costal cartilage and sternum
Sternoclavicular joints
Anterior thorax
Sternum and clavicle
Interchondral joints
Anterior thorax
“Articulation” between costal cartilages of lower ribs
Xiphosternal joint
Xiphoid and sternum
Inspiration
“Bucket handle” motion of ribs
Increase in AP and lateral diameter as well as length
Inspiration is controlled by (at rest, exercise, extreme exercise)
Rest - diaphragm
Exercise - diaphragm + external intercostals
Extreme exercise - accessory muscles (SCM & scalenes) on top of the normal controllers
Expiration is controlled by (at rest, exercise)
Rest - elastic recoil of lungs
Exercise - internal intercostals, abdominal muscles (rectus abdominus, int/ext obliques)
External intercostals action
Inspiration
Internal intercostals action
Expiration
Innermost intercostals
Elevate ribs? Not completely understood
Transversus thoracis location and action
Location: internal anterior thoracic cage
Action: expiration (depresses ribs)
Subcostal muscles location and action
Location: internal posterior thoracic cage
Action: inspiration (elevate ribs)
Levator costarum location and action
Location: external posterior attach to ribs and TP
Action: Inspiration (elevate ribs)
Serratus posterior superior action
Inspiration (elevates the ribs)
Serratus posterior inferior action
Expiration (depresses ribs)
Diaphragm innervation, action
Innervation: phrenic nerve (C3-C5)
Action: inspiration
Regions of diaphragm
Sternal
Costal
Lumbar
Intercostal nerves pathway
- 12 thoracic spinal nerves exit spinal IVF
- Each nerve branches into anterior and posterior rami
- Anterior rami supplies intercostal spaces
VAN
Each intercostal space has a bundle of vein, artery, nerve
Three major sources of circulation to thoracic wall
Thoracic aorta
Axillary artery
Subclavian artery
Branches of thoracic aorta
Posterior intercostal arteries
Subcostal artery
Posterior intercostal arteries supply
3rd-11th intercostal spaces
Subcostal artery supplies
Inferior to 12th rib
Thoracic branch of subclavian artery
Costocervical trunk
Costocervical trunk
Superior thoracic arteries branch off to supply the 1st-2nd intercostal spaces
Superior thoracic artery
Branches off of costocervical trunk of subclavian artery
Branch of subclavian artery
Costocervical trunk > Superior thoracic artery
Internal thoracic artery
Internal thoracic artery branch
Anterior intercostal arteries branch off to supply anterior 1st-9th IC spaces
Venous supply of IC spaces
Intercostal veins
Intercostal veins drain (posteriorly and anteriorly)
Posteriorly: into Azygos
Anteriorly: into internal thoracic veins
Azygos system
“Unpaired”
Drains the back and thoracoabdominal walls
Hemiazygos and Accessory hemizacygos veins
Receive blood from L side 5th-12th intercostals
Azygos vein
Receives blood from R sight intercostals, hemiazygos, accessory hemiazygos
Drains back to the heart via SVC
Left side 1st-4th IC veins drain
Directly into L brachiocephalic trunk
Nipple location
Approx. 4th IC space
Apex of heart is just inferior & medial to left nipple
Circular base of female breast extends from ____ to ____
Sternum to mid-axillary line
Ribs 2-6
Axillary tail of breast
Tail of Spence
Inferior border of pec toward axilla
Lymphatic drainage of breast
75% into axillary LNs
The rest drains medially via parasternal LNs
Trachea “begins” where
Inferior to larynx (cricoid cartilage)
Trachea cross section
D-shaped
Incomplete C shaped rings of cartilage
Carina
Bifurcation of trachea into R/L bronchi at sternal angle
Lobar bronchi
3 on right, 2 on left side
Segmental bronchi supply
the 10 bronchopulmonary segments
Cartilage disappears at
Bronchioles
Acinus
1 terminal bronchiole, many respiratory bronchioles & alveolar ducts/sacs with alveoli
Pleural lining
Visceral + parietal pleura
Visceral pleura
Lines the lungs
Parietal pleura
Lines thoracic wall and diaphragm
Pleural cavity
Space between visceral and parietal pleura
Costodiaphragmatic recess
Large pleural recess located in posterolateral region
Costomediastinal recess
Smaller pleural recess located anterolateral region (posterolateral to sternum)
Thoracentesis
Removal of fluid in IC space via hypodermic needle
Apex of lungs
Top portion
Base of lungs
Inferior portion (sits on diaphragm)
Hilum / Root of lungs
Site where lung becomes covered by visceral pleura
Contains: primary bronchus, pulmonary + bronchial vessels + lymph vessels
R lung description
3 lobes (superior, middle, inferior)
Oblique + horizontal fissures
10 bronchopulmonary segments - 3 superior, 2 middle, 5 inferior
L lung description
2 lobes (superior, inferior)
Oblique fissure only
Lingula - “similar” to middle lobe of R lung
Cardiac notch in anterior view
10 bronchopulmonary segments - 5 superior, 5 inferior lobe
Layers of heart wall
Endocardium
Myocardium
Epicardium
Pericardium
Double walled fibrous sac
Outside = fibrous
Inside = serous
-Two layers of serous (parietal and visceral)
Visceral Pericardium
Part of the serous layer of pericardium
Synonymous with epicardium
Pericardial cavity
Space between parietal and visceral layers of serous pericardium
Right atrium features
SVC/IVC openings
Coronary sinus opening
Fossa ovalis
Tricuspid valve
Fossa ovalis
A thumbprint size depression in the right atrium
Remnant of foramen ovale
Tricuspid valve
Separates R atrium and ventricle
Papillary muscles and chordae tendineae anchor cusps of the valve
Auscultate along left sternal border at 5th (or 4th) IC space
Chordae tendineae
Tendinous cords (“strings”) that connect papillary muscles to tricuspid valve
Pulmonary valve
Separates right ventricle and pulmonary artery
Auscultate along left 2nd IC space
Right ventricle features
Tricuspid valve
Papillary muscle/chordae tendineae
Pulmonary valve
Left atrium features
Foramen ovale
4 openings of pulmonary veins
Bicuspid (mitral) valve
Bicuspid valve
Mitral valve
Separates L atrium and L ventricle
Auscultate along apex (left 5th IC space)
Left ventricle features
Bicuspid valve
Papillary muscle/chordae tendineae
Aortic valve
Aortic valve
Separates left ventricle and aorta
Auscultate along right 2nd IC space
Description and function of fibrous skeleton
4 fibrous rings that surround orifices of the heart valves
Provides:
- Attachment for myocardium of atria & ventricles
- Attachment for cardiac valves
- Electrical insulation b/w atria & ventricles
SVC
Returns blood back to RA from areas superior to diaphragm (except heart and lungs)
IVC
Returns blood back to RA from areas inferior to diaphragm
Pulmonary trunk
Sends unoxygenated blood from R ventricle to lungs
R/L Pulmonary veins
Returns oxygenated blood back to LA from lungs
Aorta
Sends blood to body from L ventricle
Where do coronary arteries originate
Aorta
How and when does blood get into coronary arteries
Aortic pressure creates “backflow” gradient into coronary arteries
Occurs during early diastole (relaxation)
RCA branches and what they supply
Nodal - supply SA/AV nodes
Marginal - supplies RV
Posterior interventricular (R posterior descending) - supplies R ventricle
LCA branches and what they supply
LAD - supplies septum + L ventricle
Circumflex - supplies L atrium + L ventricle
Marginal - supplies L ventricle
Coronary veins pathway
- Most cardiac veins drain into coronary sinus
- Coronary sinus drains into RA
- Great, middle, small cardiac veins and oblique vein of LA all empty into coronary sinus
- Anterior cardiac vein and smallest cardiac veins empty directly into RA
Conducting pathway of heart
SA node AV node (1/10 sec delay allows for atrial contraction) AV bundle of His L/R bundle branch Purkinje fibers
Sternocostal surface of heart
Anterior
Mostly R ventricle
Diaphragmatic surface of heart
Inferior
Mostly L ventricle, partially R ventricle
Pulmonary surface of heart
Left
Mostly L ventricle
Point of maximal impact
Apical impulse (apex)
Mediastinum
Region in thoracic cavity between R/L pleurae
Mediastinum regions
Superior
Inferior (Anterior, Middle, Posterior)
Superior mediastinum content
- Thymus in children (remnants in adults)
- Arch of aorta/great vessels
- Trachea
- Esophagus
Anterior mediastinum content
- Internal thoracic vessels
- Fat
- Few LNs
Middle mediastinum content
Pericardium
Heart
Roots of great vessels
Posterior mediastinum content
Esophagus
Descending Aorta
Thoracic duct
LNs
CXR is taken during:
Inspiration
AP view of x-ray, heart shadow is:
Distorted/widened