Clinical Anatomy Grant S Dissector Notes (Summer 2009 and Summer 2010)
Clinical Anatomy Grant’s Dissector Notes (Summer 2009 and Summer 2010)
Melissa McDole
THE THORAX
Week #1
Day 1
Surface Anatomy—N 181
· Clavicle
o Sternoclavicular joint
o Acromioclavicular joint
· Acromion of scapula
· Jugular notch (suprasternal notch)
· Manubrium
· Sternal angle
· Body of sternum
· Xiphisternal junction
· Xiphoid process
· Seventh costal cartilage
· Costal margin
· Anterior axillary fold (lateral border of the pectoralis major muscle)
Skeleton of the Thorax
· Thoracic vertebrae
· Rib
o Head
o Neck
o Tubercle
o Costal margin
o Shaft (body)
o Costal groove
o First rib
§ Highest, shortest, broadest, and most sharply curved rib
· Costal cartilage
· True ribs (1-7)
· False ribs (8-10)--3
· Floating ribs (11-12)--2
· Sternum N186
o Jugular notch (suprasternal notch)
o Manubrium
o Sternal angle
o Body
o Xiphoid process
· Scapula N185
o Acromion
o Coracoid process
Intercostal space and muscle
· Intercostal space (dissect—space between 4 and 5 ribs)
o External intercostal muscle N426
§ Elevates ribs below it
§ Fibers are diagonal toward anterior midline as they
Descend
o Internal intercostal muscle
§ Depresses rib above
§ Fiber direction is perpendicular to fibers of external inter costal m.
o Innermost intercostal m.—N192
§ Same fiber direction and attachment and action
As the internal intercostal m.
· Serratus anterior
· Intercostal nerve
· Posterior intercostal artery and vein
o Intercostal nerves and vessels between internal intercostal muscle and innermost intercostal m.
o Intercostal nerves and vessels supply the intercostal m., skin of thoracic wall, and parietal pleura
o Order: veinàarteryà nerve
· Anterior intercostal branches of internal thoracic artery N189
o Supply anterior end of intercostal space
Removal of the anterior thoracic wall
· Costal parietal pleura
o Attaches to thoracic wall
· Right and left internal thoracic vessels
· Transversus thoracic m. N191
o Inferior attachment: on sternum
o Superior attachment: costal cartilages 2 to 6
o Depresses ribs
· Internal thoracic artery and veins
o Between the transversus thoracis m. and costal cartilages
· Follow the internal thoracic artery inferiorly and find one:
o Anterior intercostal branches
· Posterior to the sixth or seventh costal cartilage, the internal thoracic artery divides into:
o Superior epigastric artery
o Musculophrenic artery
Day 2
Lungs
Lungs in the thorax—N198
· Three surfaces of lung
o Costal
o Mediastinal
o Diaphragmatic
· Oblique fissure(major fissure)—located on both lungs
o Separate lobes of lung
· Right lung
o Horizontal fissure (minor/transverse fissure)
§ Defines middle lobe
o Three lobes
§ Superior lobe
· Lies anteriorly
§ Middle lobe
§ Inferior lobe
· Lies posteriorly
· Left lung
o Two lobes
§ Superior lobe
§ Inferior lobe
· Apex (on each lung)
o Arise as high as the neck of first rib
· Pericardium
o Contains the heart
· Root of the lung
o May be filled with clotted blood and pulmonary vessels
· Phrenic nerve
· Pericardiacophrenic vessels
· Vagus nerve—N230, 231
Removal of the lungs
· When comparing two lungs note the following:
o Right lung is shorter
o Right lung has greater volume than left lung
· Borders of the lung
o Anterior
o Posterior
o Inferior
· Cardiac notch
o On superior lobe of left lung, anterior to heart
· Lingula on left lung
o Inferior, medial portion of the superior lobe of the left lung
· Contact impressions on mediastinal surface (right lung)—N 199
o Cardiac impression
o Esophagus impression
o Arch of the azygos vein impression
o Superior vena cava impression
· Contact impression on mediastinal surface (left lung)—N 199
o Cardiac impression
o Aortic arch impression
o Thoracic aorta impression
· Hilum of the lung—N208, 209
o Main bronchus
o Pulmonary artery
o Pulmonary veins
· In left lung—N203
o Superior lobar (secondary) bronchi
o Inferior lobar (secondary bronchi
o Segmental bronchi (9)
· In right lung—
o Superior lobar bronchi (eparterial bronchus)
o Middle lobar bronchi
o Inferior lobar bronchi
o Segmental bronchi (10)
· Bronchopulmonary segment
· Bronchial artery
Mediastinum
· Mediastinum: region between two pleural cavities
· Boundaries of mediastinum:
o Superior boundary: superior thoracic aperture
o Inferior boundary: diaphragm
o Anterior boundary: sternum
o Posterior boundary: bodies of vertebrae T1 to T12
o Lateral boundaries: mediastinal parietal pleurae (left and right)
· Sternal angle
· Plane of sternal angle-- marks level of:
o Superior border of pericardium
o Bifurcation of trachea
o End of ascending aorta
o Beginning and end of arch of aorta
o Beginning of thoracic aorta
· Superior mediastinum
· Inferior mediastinum—divided by pericardium into 3 parts
o Anterior mediastinum: between sternum and pericardium—may find thymus in children
o Middle mediastinum: contains pericardium, heart, and roots of great vessels
o Posterior mediastinum: posterior to pericardium and anterior to bodies of T5 to T12; contains structures that pass between neck, thorax, and abdomen
· Four parts of mediastinum
· Mediastinal pleura—N230, 231
· Pericardium
· Root of the lung
· Esophagus (right side)
· Thoracic aorta (left side)
· Costal pleura (on side of vertebral body)
· Endothoracic fascia
o Separates costal pleura from thoracic wall
· Phrenic nerves
o Innervate diaphragm
· Left and right pericardiacophrenic vessels
o Supply diaphragm
Middle mediastinum
· Middle mediastinum
· Pericardium
o Sac enclosing the heart
o Attached to central tendon of diaphragm
· Heart
· Roots of great vessels
Heart in the thorax—N212
· Superior vena cava
· Ascending aorta
· Arch of the aorta
· Pulmonary trunk
· Ligamentum arteriosum
o Connects the left pulmonary artery to the arch of the aorta
· Left vagus nerve
o Crosses left side of aortic arch
· Left recurrent laryngeal nerve
· Right atrium
· Right ventricle
· Left ventricle
· Borders of the heart
o Right border: formed by right atrium
o Inferior border: formed by right ventricle and small part of left ventricle
o Left border: formed by left ventricle
o Superior border: formed by right and left atria and auricles
· Apex of the heart
o Part of left ventricle
o Located deep to 5th intercostal space
· Base of heart
· Parietal layer of serous pericardium
o Smooth shiny surface that lines inner pericardium
· Visceral layer of serous pericardium (epicardium)—N212
· Pericardial cavity
o Potential space between parietal and visceral layers of serous pericardium
o Contains serous fluid that lubricates serous surfaces and allows free movement of heart while in pericardium
· Oblique pericardial sinus—N215
· Transverse pericardial sinus
Day 3
Removal of the heart
· ascending aorta
· pulmonary trunk
· superior vena cava
· inferior vena cava
· four pulmonary veins
o form boundary of oblique pericardial sinus
External features of the heart
Surface features—N214
· External surfaces of heart—N214
o Coronary (atrioventricular) sulcus: runs around heart, separates atria from ventricles
o Anterior interventricular sulcus/posterior interventricular sulcus: indicate location of interventricular septum; join the coronary sulcus at a right angle
o Sternocostal (anterior) surface: formed by right ventricle
o Diaphragmatic (interior) surface: formed by left ventricle and small part of right ventricle
o Pulmonary (left) surface: formed by left ventricle; in contact with cardiac impression of left lung
o Chambers of the heart
§ right atrium and right auricle
§ right ventricle
§ left ventricle
§ left atrium and let auricle
§ Superior view
· aorta and aortic valve
· pulmonary trunk and pulmonary valve
· superior vena cava
§ Diaphragmatic surface
· Inferior vena cava
· Posterior interventricular sulcus
Cardiac veins—N216
· Cardiac veins
o Superficial to coronary arteries
· Coronary arteries
· Coronary sinus
o On diaphragmatic surface
o Located in coronary sulcus
· Great cardiac vein
o On sternocostal surface of heart
· Middle cardiac vein
o In posterior interventricular sulcus
· Small cardiac vein
o Courses along inferior border of heart
· Anterior cardiac veins
o Bridge atrioventricular sulcus between right atrium and right ventricle
o Drain anterior wall of right ventricle directly into right atrium
Coronary arteries—N216
· Aortic valve
· Right semilunar cusps
· Left semilunar cusps
· Posterior semilunar cusps
· Aortic sinus (right, left, posterior)
· Left aortic sinus
o Opening of the left coronary artery
§ anterior interventricular branch (left anterior descending LAD artery)
· follows great cardiac vein
§ Circumflex branch
o Right coronary artery
§ Opening at right aortic sinus
§ Anterior right atrial branchà
· Sinuatrial nodal branch
o Supplies sinuatrial node
§ Marginal branch
· Follows cardiac vein along inferior border of heart
§ Posterior interventricular branch
· Anastomoses with anterior interventricular branch of left coronary artery
§ Artery to the atrioventricular node
Internal features of the heart
o blood passes through the heart in the following order:
o right atrium—N220
§ anterior wall of right atrium (interior of heart)
· pectinate muscles: horizontal ridges of muscle
· crista terminalis: vertical ridge of muscle that connects pectinate muscles
§ posterior wall of right atrium
· opening of superior vena cava
· opening and valve of inferior vena cava
· opening and valve of coronary sinus
· fossa ovalis
o derived from foramen ovale
§ in fetus, blood from placenta is delivered to heart via IVC; oxygen rich blood and nutrients is directed toward foramen ovale that allows passage to left atrium and out to the body without going to the lung
· limbus fossa ovalis
§ Conduction system of the heart: on walls of atria
· Sinuatrial node (SA node)
· Atrioventricular node (AV node)
§ Right atrioventricular valve
o right ventricle—N220
§ pulmonary valve
§ anterior wall of right ventricle
§ interventricular septum
§ chordae tendineae
§ opening of the right atrioventricular valve (tricuspid valve)
· three cups:
o anterior
o septal
o posterior
§ papillary muscles
· anterior
o largest
· septal
o very small and may be multiple
· posterior
§ Trabeculae carneae
§ Septomarginal trabecula (moderator band)
§ Opening of the pulmonary trunk
§ Conus arteriosus (infundibulum)
· Cone-shaped portion of right ventricle
· Inner wall is smooth
§ Pulmonary valve
· Three semilunar cusps (anterior, right, left)—N222
· One fibrous nodule
o Help seal valve cusps and prevent backflow of blood during diastole
· Two lunules
o Help seal valve cusps and prevent backflow of blood during diastole
o left atrium—N221
§ four pulmonary veins
· arranged in pairs—two from right lung and two from left lung
§ valve of the foramen ovale
· on interatrial septum
§ opening into left auricle
§ opening of left atrioventricular valve
o left ventricle—N221
§ aortic valve
§ three semilunar valve cusps—N222
· right
· left
· posterior
§ left atrioventricular valve (bicuspid valve, mitral valve)
§ anterior cusp
§ posterior cusp
§ anterior papillary muscle
§ posterior papillary muscle
§ chordae tendineae
§ trabeculae carneae
§ aortic valve
§ right, left and posterior semilunar cusps
· one nodule and two lunules
§ muscular part of the interventricular septum
§ membranous part of the interventricular septum
§ coronary arteries
§ aortic sinuses
§ noncoronary cusp
§ conducting system of the heart—N225
· AV node
· AV bundle: two divisions
o Right bundle
§ Stimulates ventricles to contract
§ Carries impulses to anterior papillary muscle through septomarginal trabecula
o Leff bundle
§ Stimulate ventricles to contract
· Septomarginal trabecula
Week 2
Day 1
· Boundaries of the superior mediastinum
o Superior: superior thoracic aperture
o Posterior: bodies of vertebrae T1 to T4
o Anterior: manubrium of sternum
o Lateral: mediastinal pleurae (left and right)
o Inferior: plane of sternal angle
· Thymus: fatty remnant posterior to the manubrium of sternum –N 212
· Left brachiocephalic vein
· Right brachiocephalic vein
· Superior vena cava—where brachiocephalic veins meet—N230
· Azygos vein: on right side of mediastinum
· Arch of azygos vein: passes superior to root of right lung and drains into posterior surface of superior vena cava
· Right and left phrenic nerves
o Pass posterior to brachiocephalic veins
o Run with pericardiacophrenic vessels
o Enter superior surface of diaphragm
· arch of the aorta—N231
o begins and ends at level of sternal angle
o three arteries branch from arch of aorta
§ brachiocephalic trunk
§ left common carotid artery
§ left subclavian artery
· ligamentum arteriosum
o connects arch of aorta to left pulmonary artery
· left vagus nerve
· left recurrent laryngeal nerve
· right vagus nerve
· right recurrent laryngeal nerve
o loops around right subclavian artery
· trachea
o esophagus is posterior to trachea
· bifurcation of the trachea
o bifurcation occurs at the plane of the sternal angle to form the
§ right and left main bronchus
· right main bronchus has a larger diameter, is shorter and is more vertical
· tracheobronchial lymph nodes
o located around trachea near bifurcation
· tracheal rings
· carina
o special piece of tracheal cartilage
Posterior Mediastinum—N232
-structures are between the thorax and the abdomen; is posterior to pericardium
· boundaries of posterior mediastinum
o superior: plane of sternal angle
o posterior: bodies of vertebrae T5 to T12
o anterior: pericardium
o lateral: mediastinal pleura (left and right)