1. Mediastinum: Sternal angle angle Lower border of T4
It is the partition between the two pleural cavities and lungs. It includes a large number of structures
It is subdivided into:
-Superior mediastinum
-Inferior mediustinum : anterior, middle and posterior
Superior mediastinum:
Esophagus
Trachea
Arch of Aorta
Big branches of Aortic arch
Brachiocephalic ( innominate) veins
Upper half of superior vena cava
Phrenic nerves
Vagi nerves
Middle mediastinum:
Pericardium
Heart
Pulmonary trunk
Ascending Aorta
Lower half of SVC
Upper part of IVC
Bifurcation of trachea
Posterior mediastinum:
Descending thoracic Aorta
Azygos and hemiazygos veins
vagi ِ
Sternal angle
angle
Lower border
of T4

2. Fibrous and parietal layer of serous: phrenic
Pericardium:
1-It is a fibroserous sac which surrounds the heart and adjacent parts of the big vessels originating from or ending into the heart.
2-It is formed of
outer fibrous sheath-----fibrous pericardium
inner serous sac serous pericardium
Fibrous pericardium:
- Shape: conical
- Apex, base
Relations: ant, post, on each side
Serous pericardium:
-It is closed serous sac covered by fibrous
pericardium and it is invaginated by the heart
from behind and above
-Layers
3- Arterial supply and Venous drainage:
Fibrous and parietal layer of serous: internal
thoracic and descending Aorta
Visceral layer of serous-----coronary arteries and
drained into coronary sinus
5- Nerve supply:
Fibrous and parietal layer of serous: phrenic
Visceral layer of serous-----autonomic
6- Applied Anatomy: pericardial puncture

3. Heart:
-It is a pyramidal, hollow, four-chambered, muscular organ (forming the major part of middle mediastinum)
-It is formed of 4 chambers
-Atrioventricular groove (coronary sulcus)
-Anterior and inferior intervetricular grooves
-Interatrial and intervetricular septums
- Being pyramidal it has:
apex: direction, formation, site, relation
base: direction, formation, site, relation
4 surfaces: sternocostal, diaphragmatic, right and left surfaces
each: direction, formation, site
Post. I.V. groove
Ant. I.V. groove

5. Right Atrium: Cavity of RA: -Site Post-----sinus venarum (smooth)
-Receives venous blood from whole body
SVC---upper post.
IVC----lower post Sulcus terminalis
-Right auricle
Cavity of RA:
Post-----sinus venarum (smooth)
Ant------atrium proper (rough) crista terminalis
(musculi pectinati)
Interatrial septum shows-----fossa ovalis
Opening in RT:
SVC, IVC, coronary sinus, tricuspid opening

6. Right Ventricle: -Site Cavity of RV:
Inflow part----- (rough)----trabeculae carnae (muscular projections)
----Papillary muscles----Chordae tendinae supporting the tricuspid valve
Outflow part-----(smooth)-----infundibulum (why?)
Interventricular septum
Opening in RV:
Tricuspid opening and valve
Pulmonary opening and valve

7. Left Atrium: Cavity of RA: Post----- (smooth) receives pulmonary veins
-Site
-Receives 4 pulmonary veins
-Left auricle
Cavity of RA:
Post----- (smooth) receives pulmonary veins
Ant (rough) left auricle
Opening in RT:
4 pulmonary veins
Mitral opening

8. Left Ventricle: Pulmonary valve -Site Cavity of LV: Aortic valve
Inflow part----- (rough)----trabeculae carnae (muscular projections)
Outflow part-----(smooth)-----vestibule (why?)
Interventricular septum
Thickness
Opening in LV:
Mitral opening and valve
Aortic opening and valve
Pulmonary valve
Aortic valve
Tricuspid
valve
Mitral valve
Papillary muscle

9. Conducting system of the heart:
Formed of modified myocardial fibers called (Purkinje fibers) which are specialized for initiation,
conduction and maintenance of the cardiac rhythm.
1- Sinoatrial (SA) node-----site, function
2- Atrioventricular (AV) node-----site
3- Atrioventricular (AV) bundle-----right , left branches

10. Post. Ant. Nerve supply of the heart: Arterial supply of the heart:
1- Sympathetic innervation:
Stimulates heart rate (tachycardia)
coronary vasodilatation
2- Paraympathetic innervation:
Slows heart rate (bradycardia)
Coronary vasoconstriction
3- Pain fibers: upper thoracic segments of
the spinal cord
Arterial supply of the heart:
1- right coronary artery:
Origin, Course, branches
2- Left coronary artery:
Origin, Course, divisions, branches
Venous drainage of the heart:
1- Coronary sinus: Legnth, site, receives all
venous drainage of the heart as:
great, middle and small cardiac veins
Coronary sinus
Lt coronary A.
Circumflex A.
Rt coronary A.
Ant. IV A.
+great cardiac V.
Post. IV A.
+middle cardiac V.
Ant.
Post.