Objectives 2.1 Thorax - Ross University Anatomy Instructional Site

Osteology

Clavicle:

Sternal end
Acromial end

Sternum:

Manubrium
- Jugular notch
Sternal angle
Body
Xiphoid process

Scapula:

Acromion
Coracoid process

Ribs:

Head
Neck
Tubercle
Shaft (body)
Costal groove
First rib
True ribs (ribs 1 – 7)
False ribs (ribs 8 – 12)
Floating ribs (ribs 11 & 12)
Costal margin
Costal cartilage

Boundaries of the Mediastinum

Superior boundary (superior thoracic aperture)
Inferior boundary (diaphragm)
Anterior boundary (sternum)
Posterior boundary (bodies of vertebrae T1 to T12)
Lateral boundaries (left and right mediastinal pleurae)

Regions of the Mediastinum

Anterior mediastinum: between sternum and pericardium
Posterior mediastinum: posterior to pericardium and anterior to vertebrae T5‐T12
Middle mediastinum: contains pericardium, heart and great vessels
Superior mediastinum: above the plane of sternal angle (at T4/T5 vertebral level)

Boundaries of the Superior Mediastinum

- Superior: superior thoracic aperture
- Posterior: bodies of vertebrae T1-T4
- Anterior: manubrium of sternum
- Lateral: mediastinal pleurae
- Inferior: plane of sternal angle

Posterior Mediastinum Boundaries

- Superior: plane of sternal angle
- Posterior: bodies of vertebrae T5-T12
- Anterior: pericardium
- Lateral: mediastinal pleurae
- Inferior: diaphragm

Fascia and Pleura:

Endothoracic fascia
Visceral pleura (pulmonary pleura)
Parietal pleura:
- Left and right pleural cavities
  - Costal pleura
  - Mediastinal pleura
  - Diaphragmatic pleura
  - Cervical pleura (cupula)
Pleural recesses
- Costomediastinal recess
- Costodiaphragmatic recess
- Costovertebral recess

Muscles

External intercostal muscle
Internal intercostal muscle
Innermost intercostal muscle
Serratus anterior muscle
Diaphragm

Arteries

Arch of aorta and its branches:
- Brachiocephalic trunk/artery
- Left common carotid artery
- Left subclavian artery
Thoracic (descending) aorta and its branches:
- Esophageal arteries
- Left bronchial arteries
- Posterior intercostal arteries
  - right bronchial arteries
Internal thoracic artery:
- Superior epigastric artery
- Musculophrenic artery
- Anterior intercostal arteries

Veins

Azygos vein (including arch)
Hemiazygos vein
Accessory hemiazygos vein
Posterior intercostal veins
Internal thoracic veins
Anterior intercostal veins
Left and right brachiocephalic veins
Superior vena cava
Inferior vena cava

Nerves

Vagus nerves- left & right (note their posterior relationship with root of lung)
Intercostal nerves
Sympathetic trunk
Sympathetic ganglia
Greater splanchnic nerves (T5-T9)
Lesser splanchnic nerves (T10-T11)
Least splanchnic nerves (T12)
Esophageal plexus of nerves (sympathetic + parasympathetic fibers)
Anterior and posterior vagal trunks
Phrenic nerves- left & right (note anterior relationship with root of lung)
Recurrent laryngeal nerves- left & right

Organs

Thymus
Lungs
- Borders of the lungs: anterior, posterior, and inferior
- Fissures: oblique (major) fissure, horizontal (minor or transverse) fissure
- Surfaces of the lungs:
  - Costal
  - Mediastinal
  - Diaphragmatic
  - Apex
- Three lobes of the right lung:
  - Superior lobe
  - Middle lobe
  - Inferior lobe
- Two lobes of the left lung
  - Superior lobe
    - Cardiac notch
    - Lingula
  - Inferior lobe

Contact Impressions on the lungs:

Right lung:
- Cardiac impression
- Esophagus impression
- Arch of azygos vein impression
- Superior vena cava impression

Left lung:
- Cardiac impression
- Aortic arch impression
- Thoracic aorta impression

Structures at the Hilum of the Lung:

Hilum of the right lung:
- Main bronchus (primary bronchus)
- Lobar bronchus (secondary bronchus)
- Pulmonary artery
- Pulmonary veins
Hilum of left lung:
- Main bronchus (or primary bronchus)
- Lobar bronchus (or secondary bronchus)
- Pulmonary artery
- Pulmonary veins
Pulmonary ligament- left & right

Miscellaneous Viscera

Trachea (superior mediastinum)
- Bifurcation of trachea
- Right main bronchus & left main bronchus
- Carina
- Tracheobronchial lymph nodes (carinal lymph nodes)
Esophagus (superior and posterior mediastinum)
Thoracic duct (superior and posterior mediastinum)

The Heart:

Pericardium
- Fibrous pericardium
- Serous pericardium
  - Parietal layer
  - Visceral layer (epicardium)
Pericardial cavity
- Oblique pericardial sinus
- Transverse pericardial sinus
Ligamentum arteriosum
Chambers of Heart:
- Right atrium
- Left atrium
- Right ventricle
- Left ventricle
Surfaces of Heart:
- Sternocostal (anterior) surface
- Diaphragmatic (inferior) surface
- Left pulmonary surface
- Right pulmonary surface
- Apex of heart
- Base of heart
Sulci (grooves) of heart:
- Coronary sulcus (atrioventricular sulcus)
- Anterior interventricular sulcus
- Posterior interventricular sulcus
Cardiac Veins:
- Coronary sinus
- Great cardiac vein
- Middle cardiac vein
- Small cardiac vein
- Anterior cardiac veins
Coronary Arteries and branches:
- Left coronary artery
  - Anterior interventricular artery (LAD = left anterior descending artery)
  - Circumflex artery
- Right coronary artery
  - Anterior right atrial artery
  - Sinoatrial nodal artery
  - Right marginal artery
  - Posterior interventricular artery
  - Atrioventricular nodal artery
Internal Features of the Heart:
- Right Atrium
  - Right auricle
  - Pectinate muscle
  - Crista terminalis
  - Opening of superior vena cava
  - Opening of inferior vena cava
  - Opening of coronary sinus
  - Interatrial septum
  - Fossa ovalis
  - Sinoatrial (SA) node
  - Atrioventricular (AV) node
  - Right atrioventricular valve (tricuspid valve)
    - Anterior cusp
    - Septal cusp
    - Posterior cusp
- Left Atrium
  - Left auricle
  - Pulmonary veins
  - Interatrial septum
  - Left atrioventricular (mitral/bicuspid) valve
- Right Ventricle
  - Interventricular septum
  - Chordae tendineae
  - Atrioventricular (tricuspid) valve and its three cusps
  - Anterior papillary muscle
  - Septal papillary muscle(s)
  - Posterior papillary muscle
  - Trabeculae carneae
  - Moderator band (septomarginal trabecula)
  - Conus arteriosus (infundibulum)
  - Pulmonary valve
    - Right, left, and anterior semilunar cusps

- Left Ventricle
  - Aortic valve
    - Right, left, and posterior semilunar cusps
    - Right, left, and posterior aortic sinuses
  - Left atrioventricular valve (mitral/bicuspid valve)
    - Anterior and posterior cusps
    - Anterior papillary muscle
    - Posterior papillary muscle
    - Chordae tendineae
    - Trabeculae carneae
    - Interventricular septum
    - Opening to left coronary artery
    - Opening to right coronary artery

Clinical Correlations

Relationship of esophagus to heart and aorta throughout mediastinal course
Esophageal constriction- sites, causes (pathologic and non-pathologic)
Paradoxical motion of diaphragm
Injury to recurrent laryngeal nerves- causes, signs and symptoms, treatment
Bifurcation of the trachea and aspiration of foreign bodies
Mediastinal mass lesions
- Surgical significance of transverse pericardial sinus
- Pericarditis and pericardial effusion/rub
- Cardiac tamponade
Embryology of heart and system defects- understand the embryological origin of the structures seen in the adult heart:
- Fossa ovalis
- Ligamentum arteriosum
- Atria
- Ventricles
- Pulmonary trunk
- Aorta
Congenital heart defects (relate embryo lectures to adult structures you see in lab):
- Dextrocardia
- Probe patent foramen ovale
- Patent ductus arteriosus
- Coarctation of the aorta
- Tetralogy of Fallot
Auscultation of heart valves
- Projected location of each valve on the chest wall
- Best location to auscultate each valve on the chest wall
Myocardial infarction (vessels involved, collateral circulation)
Rib fractures, flail chest
Sternal deformities (pectus excavatum, pectus cavinatum)
Thoracic outlet syndrome (TOS)
Intercostal nerve block & layers pierced
Pleural fluid, pleural tap (thoracocentesis), chest tube, location
Pleural effusion
Pneumothorax, hemothorax, hydrothorax, chylothorax, pyothorax
Injury to lungs: pulmonary collapse (tension pneumothorax, associated mediastinal shift)
Pulmonary embolism
Lymphatic drainage and spread of cancer