Advertisements help pay for this website. Thank you for
Blood vessels and
nerves of the heart | Main Anatomy Index | Manubriosternal plane
Last updated 30 March 2006
- The pericardium (G. around the heart) is a double-walled
fibroserous sac that encloses the heart (G. kardia) and the roots of the
- It is located in the middle
mediastinum, posterior to the body of the sternum and the 2nd to
6th costal cartilages, and anterior to T5 to T8 vertebrae.
- The pericardium consists of two parts: (1) a strong
external layer composed of tough fibrous tissue, called the fibrous
pericardium, and (2) an internal double-layered sac composed of a transparent membrane
called the serous pericardium.
The Fibrous Pericardium
- The fibrous pericardium is the tough, more or less conical outer sac of pericardium,
which protects the heart against sudden overfilling.
- Its truncated apex is pierced by the aorta, pulmonary
trunk, and SVC.
- The ascending aorta carries the pericardium superiorly beyond the
heart to the level of the sternal angle.
- The external surface of the fibrous pericardium has a dull appearance and its base rests
on and is fused with the central tendon of the diaphragm.
- Anteriorly, the fibrous pericardium is attached to the posterior surface of the sternum
by condensations of connective tissue called sternopericardial
- The fibrous pericardium is also fused with the tunica adventitia
of the great vessels.
- Thus, the fibrous pericardial sac is influenced by movements of the sternum, diaphragm
- The central tendon of the diaphragm and the pericardium are pierced
by the IVC on the right side.
- The fibrous pericardium extends 1 to 1.5 cm to the right of the sternum and 5 to 7.5 cm
to the left of the median plane at the level of the 5th intercostal space.
- It is separated by the sternum and costal cartilages of the 2nd to 6th
ribs by the lungs and pleura,
except where it is attached to the posterior surface of the sternum by the sternopericardial ligaments and where the bulge of the heart
The Serous Pericardium
- The serous pericardium consists of two layers: a parietal pericardium and a visceral
- The parietal pericardium is fused to the internal
surface of the fibrous pericardium and is so closely
adherent to it that they are difficult to separate.
- The visceral pericardium is reflected onto the heart
where it forms the epicardium, the external layer of the
- The potential space between the parietal and visceral layers of the serous pericardium
is called the pericardial cavity.
- It normally contains a thin film of serous fluid that enables the
heart to move and beat in a frictionless environment.
- The visceral pericardium is reflected from the heart and great
vessels to become continuous with the parietal pericardium. This is where the
aorta and pulmonary trunk leave the heart and the superior and inferior venae cavae and
pulmonary veins enter the heart.
The Pericardial Sinuses
- The sinuses of the pericardium develop during folding of the
embryonic heart, a process that produces reflections in the pericardium.
- When the pericardial sac is opened anteriorly, a digit
can be inserted into a recess posterior to the ascending aorta and
pulmonary trunk, and anterior to the SVC.
- This recess is known as the transverse pericardial sinus.
- At its left and right ends, it communicates with the main part of the pericardial
The Oblique Pericardial
- As the pulmonary veins and IVC penetrate the fibrous pericardium to enter the heart, they bulge into the pericardial cavity.
- Consequently, they are partly covered by serous pericardium, which forms a somewhat
inverted, U-shaped blind recess, called the oblique pericardial
- It is a wide, slit-like recess posterior to the heart that extends posterior
to the left atrium.
- The thoracic part of the IVC is to the right of this
- The oblique pericardial sinus, which can be entered inferiorly, will admit several
digits; however, they cannot pass around any of the vessels because this sinus is a blind sinus (cul-de-sac).
- There is a close relationship between the transverse and oblique pericardial sinuses.
Only two layers of serous pericardium separate them.
of the Pericardium
- Its main arteries are the pericardiacophrenic and musculophrenic arteries, which are branches of the internal thoracic arteries.
- It also receives pericardial branches from the bronchial, oesophageal, and superior phrenic arteries.
- The epicardium is supplied by the coronary
of the Pericardium
- Its veins are tributaries of the azygos systems of veins.
- Pericardiacophrenic veins also enter the internal thoracic veins.
Innervation of the
- The nerves of the pericardium are derived from the vagus
and phrenic nerves and the sympathetic