QS Study

The pericardium is a conical fibro-serous sac which encloses the heart and the root of the great vessels except for inferior vena cava and lies within the middle mediastinum. It is the membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane.

Arterial supply

Fibrosis and parietal pericardium: By –

(i) Internal thoracic artery,

(ii) Musculophrenic artery.

(iii) Descending thoracic aorta.

Visceral pericardium: By –

(i) Right coronary artery.

(ii) Left coronary artery.

Venous drainage

Fibrous and parietal pericardium: Into (i) Azygos vein and (ii) Internal thoracic vein.

Visceral pericardium: Into coronary sinus.

Fig: Pericardium: Arterial Supply and Nerve supply 

Nerve supply

The fibrous pericardium and parietal layer of the serous pericardium are supplied by the phrenic nerves. The visceral layer of the serous pericardium is supplied by the branches of sympathetic trunks and vagus nerves. Thus fibrous pericardium and parietal layer of the visceral pericardium are sensitive to pain on the other hand visceral layer of the pericardium is insensitive to pain.

Fibrous and parietal pericardium: Phrenic nerve (C3,C4,C5).

Visceral pericardium (autonomic supply):

(i) Sympathetic: By TI-5 segments.

(ii) Parasympathetic: By vagus.

Functions – The pericardium has many physiological roles, the most important of which are detailed below.

(1) It prevents overdistension of heart.

(2) It prevents friction of heart.

(3) It maintains the position of the heart.

(4) It protects and lubricates your heart and keeps it in place within your chest.

The fibrous pericardium serves as a physical barrier between the muscular body of the heart and adjacent organs prone to infection, such as the lungs. Problems can occur when the pericardium becomes inflamed or fills with fluid. The swelling can damage your heart and affect its function.

Development

(1) Fibrous pericardium: Develops from septum transverse.

(2) Parietal: From somatopleuric layer of lateral plate mesoderm.

(3) Visceral: Form splanchnopleuric layer of lateral plate mesoderm.

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